Beethoven
November 12, 2005, 08:47 PM
As titled.
Thanks!
Thanks!
What specific qualities make the AK so reliable?
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DnPRK
November 12, 2005, 09:04 PM
Two things make it reliable:
1. Sloppy tolerances that don't care if dirt or mud get into the action
2. A truly rugged magazine
1. Sloppy tolerances that don't care if dirt or mud get into the action
2. A truly rugged magazine
DMK
November 12, 2005, 09:08 PM
Two things make it reliable:
1. Sloppy tolerances that don't care if dirt or mud get into the action
2. A truly rugged magazine It's not loose tolerances, it's loose clearances. Loose tolerances is just sloppy manufacturing (or maybe intentionally allowing for sloppy manufacturing). Loose clearances is an intentional design feature that allows for space between the parts.
The AK does have a very well designed magazine (except for the lack of a last shot bolt hold open).
I'd also have to add simplicity and generously proportioned parts as a design feature that increases the reliability of the rifle. A complex rifle with many small parts is going to have a much larger chance of parts failure that a simple rifle with fewer and larger parts. There aren't many tiny parts on an AK.
1. Sloppy tolerances that don't care if dirt or mud get into the action
2. A truly rugged magazine It's not loose tolerances, it's loose clearances. Loose tolerances is just sloppy manufacturing (or maybe intentionally allowing for sloppy manufacturing). Loose clearances is an intentional design feature that allows for space between the parts.
The AK does have a very well designed magazine (except for the lack of a last shot bolt hold open).
I'd also have to add simplicity and generously proportioned parts as a design feature that increases the reliability of the rifle. A complex rifle with many small parts is going to have a much larger chance of parts failure that a simple rifle with fewer and larger parts. There aren't many tiny parts on an AK.
Sunray
November 12, 2005, 09:25 PM
"...not sloppy tolerances, it's loose clearances..." Loose clearances are the same thing as loose tolerances.
The AK was designed to go bang every time in combat. Not for target shooting accuracy. It'll keep going despite a lack of user maintenance, poor ammo and the dirt and crud getting into it. Loose tolerances allow this. 'Loose' doesn't mean sloppy though. Sloppy tolerances are those that are too big. They will cause jamming etc. Parts will not fit properly and those that must move in a straight line, won't.
The AK was designed to go bang every time in combat. Not for target shooting accuracy. It'll keep going despite a lack of user maintenance, poor ammo and the dirt and crud getting into it. Loose tolerances allow this. 'Loose' doesn't mean sloppy though. Sloppy tolerances are those that are too big. They will cause jamming etc. Parts will not fit properly and those that must move in a straight line, won't.
DMK
November 12, 2005, 09:38 PM
"...not sloppy tolerances, it's loose clearances..." Loose clearances are the same thing as loose tolerances. No they are not. Clearances (http://dictionary.reference.com/search?q=clearance) are the spaces between parts. Tolerances (http://dictionary.reference.com/search?q=tolerance) are how big or small a part may be before it gets rejected as "out of spec". Or more precisely, tolerance is how far a part may deviate (plus or minus) from the specified dimensions.
Now a wide tolerance range may sometimes give you wide clearances (if two fitted parts are undersized), but it may also just as often give you parts that fit very tight if two fitted parts are both oversized.
Loose(generous) tolerances are not a good thing.
Now a wide tolerance range may sometimes give you wide clearances (if two fitted parts are undersized), but it may also just as often give you parts that fit very tight if two fitted parts are both oversized.
Loose(generous) tolerances are not a good thing.
jefnvk
November 12, 2005, 10:01 PM
Arguing over semantics again.
There is a lot more space between the parts in an AK, say than an AR. It leads to better reliability, but since the parts have a bit more 'wiggle' (for lack of a better word) room, not so great accuracy.
There is a lot more space between the parts in an AK, say than an AR. It leads to better reliability, but since the parts have a bit more 'wiggle' (for lack of a better word) room, not so great accuracy.
Preacherman
November 12, 2005, 10:40 PM
Arguing over "clearance" versus "tolerance" aside (and I agree that "clearance" is the better word), the AK is built to cope with grit, mud, etc. in the action and continue operation. The M16/AR-15 will "choke" on mud, etc., whereas the AK will go right on shooting in conditions that would gag a maggot.
Another factor in its reliability is the gas system. It uses a LOT of gas (comparatively speaking) to force the piston to the rear. This helps to blast debris out of the gas system and keep it operational. The M16's gas tube is a tiny thing, that can easily be clogged, and won't be "blown clear" by the small volume of gas tapped out of the barrel to cycle the action.
Finally, the AK was built with snowy, muddy Eastern Front conditions in mind. After all, that's the entire combat experience of the Soviet Army at the time! The M16 was designed by a geek who hadn't used weapons outside a shooting-range environment... and it showed, particularly in the early iterations of the weapon (which weren't helped by the Army's tinkering with Stoner's specifications for weapon and ammunition).
Another factor in its reliability is the gas system. It uses a LOT of gas (comparatively speaking) to force the piston to the rear. This helps to blast debris out of the gas system and keep it operational. The M16's gas tube is a tiny thing, that can easily be clogged, and won't be "blown clear" by the small volume of gas tapped out of the barrel to cycle the action.
Finally, the AK was built with snowy, muddy Eastern Front conditions in mind. After all, that's the entire combat experience of the Soviet Army at the time! The M16 was designed by a geek who hadn't used weapons outside a shooting-range environment... and it showed, particularly in the early iterations of the weapon (which weren't helped by the Army's tinkering with Stoner's specifications for weapon and ammunition).
beerslurpy
November 12, 2005, 10:57 PM
The parts of the gun have a lot of clearance.
The cartridge is wedge shaped so it doesnt engage the chamber walls except when full seated.
The gas piston is massively oversized. It would still work with half as much piston area.
The fire control group is simple and sturdy.
The extractor is sturdy.
The receiver has empty space in it for dirt to get pushed out of the way.
The cartridge is wedge shaped so it doesnt engage the chamber walls except when full seated.
The gas piston is massively oversized. It would still work with half as much piston area.
The fire control group is simple and sturdy.
The extractor is sturdy.
The receiver has empty space in it for dirt to get pushed out of the way.
brentwal
November 13, 2005, 12:27 AM
They're over built for the cartridge they fire.
That and they'er looser than a $5 hooker.
That and they'er looser than a $5 hooker.
natedog
November 13, 2005, 12:36 AM
http://en.wikipedia.org/wiki/Eugene_Stoner
"During World War II, he enlisted for Aviation Ordnance in the Marines and served in the South Pacific and northern China"
"During World War II, he enlisted for Aviation Ordnance in the Marines and served in the South Pacific and northern China"
3rdpig
November 13, 2005, 12:44 AM
DMK - Give it up, you'll never get the forum crowd to admit there's a difference between "clearance" and "tolerance", I tried for years before giving up, to them it's just two different ways of saying the same thing. Not being machinists they don't even know a specification even exists or what it's for. Ignorance is bliss, just leave them to it.
As far as the AK reliability is concerned, besides good durable mags and large clearances, the brute force gas system is another feature that adds to it's reliability...and detracts from it's accuracy as well. Chrome lined barrels play a part as well as it's utter simplicity. The fact that it can't be disassembled past field stripping was another plus, considering the people that normally use it.
As far as the AK reliability is concerned, besides good durable mags and large clearances, the brute force gas system is another feature that adds to it's reliability...and detracts from it's accuracy as well. Chrome lined barrels play a part as well as it's utter simplicity. The fact that it can't be disassembled past field stripping was another plus, considering the people that normally use it.
Crosshair
November 13, 2005, 01:13 AM
One very important factor to the reliability is that the AK bolt and bolt carrier ride on the gas piston and recoil spring. The rails inside the reciever have no function other than to guide the reciprocating parts (and hold the ejector) inside the reciever. This allos for a large amount of crud to be inside and still function.
dogngun
November 13, 2005, 09:06 AM
Reliability is what this weapon is all about - it was designed to workunder extreme conditions and to be used by someone with no experience with machines.
It is simple,yet it's simplicity is well thought out, it's overbuil, rugged, and easy to learn to shoot.
Mark
It is simple,yet it's simplicity is well thought out, it's overbuil, rugged, and easy to learn to shoot.
Mark
Kaylee
November 13, 2005, 09:53 AM
All the above, with a "thank you" to DMK.
One more thing.. we never fielded it as a service rifle, so we don't have folks coming home and spreading "it stinks" stories about every single time it failed. Greener grass, as it were. :p
One more thing.. we never fielded it as a service rifle, so we don't have folks coming home and spreading "it stinks" stories about every single time it failed. Greener grass, as it were. :p
geekWithA.45
November 13, 2005, 10:33 AM
The wedge shaped cartridge has a lot to do with it.
It'll tolerate more junk in the chamber and still slam into battery than a straightwall.
It'll tolerate more junk in the chamber and still slam into battery than a straightwall.
1911user
November 13, 2005, 10:49 AM
The parts of the gun have a lot of clearance.
The cartridge is wedge shaped so it doesnt engage the chamber walls except when full seated.
The gas piston is massively oversized. It would still work with half as much piston area.
The fire control group is simple and sturdy.
The extractor is sturdy.
The receiver has empty space in it for dirt to get pushed out of the way.
I'll add one more to this good list:
The bolt carrier has alot of mass which ensures enough energy to extract and seat the cartridge case under dirty conditions. This large reciprocating mass hurts accuraccy and makes full-auto fire less controlable. The closest example I can think of is a slide-hammer like used in auto body work for pulling dents.
The cartridge is wedge shaped so it doesnt engage the chamber walls except when full seated.
The gas piston is massively oversized. It would still work with half as much piston area.
The fire control group is simple and sturdy.
The extractor is sturdy.
The receiver has empty space in it for dirt to get pushed out of the way.
I'll add one more to this good list:
The bolt carrier has alot of mass which ensures enough energy to extract and seat the cartridge case under dirty conditions. This large reciprocating mass hurts accuraccy and makes full-auto fire less controlable. The closest example I can think of is a slide-hammer like used in auto body work for pulling dents.
Zeke/PA
November 13, 2005, 11:04 AM
Simplicity, Simplicity, Simplicity!!!!!!
Zeke
Zeke
Fletchette
November 13, 2005, 01:04 PM
Many of the reasons cited for the AK's reliability are false arguemnts. For example, if it were loose tolerances/clearances, then the AR-15 should become more reliable with sloppy workmanship. Not true.
Gaps for "crud to fall out" are gaps for "crud to get in".
The two reasons mentioned that may have some merit is the wedge shaped cartidge (I have also thought the same about 9mm) and the long-stroke oversized piston. The long-stroke has more reciprocating mass, usually considered a negative, but this adds momentum to the bolt so it can plow through crud.
Gaps for "crud to fall out" are gaps for "crud to get in".
The two reasons mentioned that may have some merit is the wedge shaped cartidge (I have also thought the same about 9mm) and the long-stroke oversized piston. The long-stroke has more reciprocating mass, usually considered a negative, but this adds momentum to the bolt so it can plow through crud.
beerslurpy
November 13, 2005, 01:43 PM
The people talking about loose tolerances are misusing the word, so ignore them.
They mean that, like the glock, the AK has clearance between the moving parts so that grease and dirt that gets trapped in between wont seize up the weapon. Instead, the cycling of the weapon pushes the dirt out before it can build up. As long as the clearances are tight enough to get the bolt attached to the back of the cartridge by the time it rotates and locks, the weapon will work and it will produce repeatable results.
Another thing that I agree with is that you can take the gun apart without tools and there are no small parts to lose. This is a big deal in a weapon meant to be cleaned in the field.
They mean that, like the glock, the AK has clearance between the moving parts so that grease and dirt that gets trapped in between wont seize up the weapon. Instead, the cycling of the weapon pushes the dirt out before it can build up. As long as the clearances are tight enough to get the bolt attached to the back of the cartridge by the time it rotates and locks, the weapon will work and it will produce repeatable results.
Another thing that I agree with is that you can take the gun apart without tools and there are no small parts to lose. This is a big deal in a weapon meant to be cleaned in the field.
SkunkApe
November 13, 2005, 06:10 PM
No they are not. Clearances (http://dictionary.reference.com/search?q=clearance) are the spaces between parts. Tolerances (http://dictionary.reference.com/search?q=tolerance) are how big or small a part may be before it gets rejected as "out of spec". Or more precisely, tolerance is how far a part may deviate (plus or minus) from the specified dimensions.
Now a wide tolerance range may sometimes give you wide clearances (if two fitted parts are undersized), but it may also just as often give you parts that fit very tight if two fitted parts are both oversized.
Loose(generous) tolerances are not a good thing.
DMK is correct. I speak from 20 years in manufacturing engineering.
Stop saying "tolerance" instead of "clearance" (or "fit"), or I'm gonna say "clip" instead of "magazine".
clip clip clip clippity clip clip
Now a wide tolerance range may sometimes give you wide clearances (if two fitted parts are undersized), but it may also just as often give you parts that fit very tight if two fitted parts are both oversized.
Loose(generous) tolerances are not a good thing.
DMK is correct. I speak from 20 years in manufacturing engineering.
Stop saying "tolerance" instead of "clearance" (or "fit"), or I'm gonna say "clip" instead of "magazine".
clip clip clip clippity clip clip
Dr.Rob
November 13, 2005, 07:33 PM
Kalashnikov insisted on a chromed bore and designed it to fire even if you poured a handful of sand into the action.
That's a designed spec, not an accident of sloppy machining.
That's a designed spec, not an accident of sloppy machining.
clange
November 13, 2005, 08:00 PM
Many of the reasons cited for the AK's reliability are false arguemnts. For example, if it were loose tolerances/clearances, then the AR-15 should become more reliable with sloppy workmanship. Not true.
That logic doesnt hold up. As others have said, large clearances are not due to sloppy workmanship. Sloppy workmanship can just as easily create large clearances as well as clearances that are too small. The AK was designed around large clearances, the AR wasnt, so if some AR part has poor tolerances creating a clearance that is too large it can cause problems because it wasnt designed to function that way. Both can obviously have problems if clearances are too tight.
That IS a big part of the reliability. 1) It allows for more room between parts if there is dirt/crud and 2) it can tolerate sloppy workmanship should it turn out a part that is slightly oversized (making clearances smaller). Loose tolerances (either way) dont affect the AK as much as an AR because the AR was designed with much less forgiving clearances.
That logic doesnt hold up. As others have said, large clearances are not due to sloppy workmanship. Sloppy workmanship can just as easily create large clearances as well as clearances that are too small. The AK was designed around large clearances, the AR wasnt, so if some AR part has poor tolerances creating a clearance that is too large it can cause problems because it wasnt designed to function that way. Both can obviously have problems if clearances are too tight.
That IS a big part of the reliability. 1) It allows for more room between parts if there is dirt/crud and 2) it can tolerate sloppy workmanship should it turn out a part that is slightly oversized (making clearances smaller). Loose tolerances (either way) dont affect the AK as much as an AR because the AR was designed with much less forgiving clearances.
Texfire
November 13, 2005, 08:03 PM
DMK is correct. I speak from 20 years in manufacturing engineering.
Stop saying "tolerance" instead of "clearance" (or "fit"), or I'm gonna say "clip" instead of "magazine".
clip clip clip clippity clip clip
Excuse me sir, you can't say clip on an airplane. ;)
Stop saying "tolerance" instead of "clearance" (or "fit"), or I'm gonna say "clip" instead of "magazine".
clip clip clip clippity clip clip
Excuse me sir, you can't say clip on an airplane. ;)
Bartholomew Roberts
November 13, 2005, 08:13 PM
Many of the reasons cited for the AK's reliability are false arguemnts. For example, if it were loose tolerances/clearances, then the AR-15 should become more reliable with sloppy workmanship. Not true.
I think you are extrapolating too much. Firearms are designed as systems and you can't take one aspect of one system and transfer it to a totally different system and expect everything to work just fine. Look at the many failed attempts to produce a gas-piston AR15 for an example of this concept.
The AR15 was designed to work with tight clearances by keeping dirt out of the action as much as possible. Just one example is the addition of the dust cover to the ejection port and changing from the hook-shaped charging handle of the AR10 to the now-familiar T-charging handle.
An AK-47 is designed to help dirt migrate out of the receiver through the large clearances. The large clearances aren't responsible for the difference all by themselves; but they work as part of the design. Different approaches to the same problem; but it doesn't mean that you can take a rifle designed around tight clearances and then change the clearances and it will automatically start working more reliably.
I think you are extrapolating too much. Firearms are designed as systems and you can't take one aspect of one system and transfer it to a totally different system and expect everything to work just fine. Look at the many failed attempts to produce a gas-piston AR15 for an example of this concept.
The AR15 was designed to work with tight clearances by keeping dirt out of the action as much as possible. Just one example is the addition of the dust cover to the ejection port and changing from the hook-shaped charging handle of the AR10 to the now-familiar T-charging handle.
An AK-47 is designed to help dirt migrate out of the receiver through the large clearances. The large clearances aren't responsible for the difference all by themselves; but they work as part of the design. Different approaches to the same problem; but it doesn't mean that you can take a rifle designed around tight clearances and then change the clearances and it will automatically start working more reliably.
Oleg Volk
November 13, 2005, 08:19 PM
AFAIK, the other reason is that the bolt carrier is designed to over-travel to the rear, so short-stroking is less likely.
longeyes
November 13, 2005, 08:24 PM
They're over built for the cartridge they fire.
That and they'er looser than a $5 hooker.
The more I hear the more I want one.:D
That and they'er looser than a $5 hooker.
The more I hear the more I want one.:D
Cosmoline
November 13, 2005, 08:55 PM
Gaps for "crud to fall out" are gaps for "crud to get in".
But in the case of the AK, the hole in the barrel is so huge and the piston housing so oversized that any unburned powder, bits of copper debris or whatever that fly up in there won't do diddly to interfere with the function. You'd have to fire it an enormous amount to actually clog the hole, and frankly I'm not sure it could be done.
But in the case of the AK, the hole in the barrel is so huge and the piston housing so oversized that any unburned powder, bits of copper debris or whatever that fly up in there won't do diddly to interfere with the function. You'd have to fire it an enormous amount to actually clog the hole, and frankly I'm not sure it could be done.
benEzra
November 13, 2005, 10:38 PM
AFAIK, the other reason is that the bolt carrier is designed to over-travel to the rear, so short-stroking is less likely.
Oleg beat me to it. A very big reason is the fact that the bolt carrier has a LONG throw; it travels way to the rear of the magazine, so the bolt gets a long running start before hitting the top round in the mag. Not only does it make short-stroking more likely, but it allows a higher bolt carrier velocity in the first few inches (reduces likelihood of jams) without requiring high spring rates. Not the best thing for accuracy, but fantastic for reliability.
Oleg beat me to it. A very big reason is the fact that the bolt carrier has a LONG throw; it travels way to the rear of the magazine, so the bolt gets a long running start before hitting the top round in the mag. Not only does it make short-stroking more likely, but it allows a higher bolt carrier velocity in the first few inches (reduces likelihood of jams) without requiring high spring rates. Not the best thing for accuracy, but fantastic for reliability.
Fletchette
November 14, 2005, 12:21 AM
I'll agree that the bolt over-travel, along with the heavy, momentum laden bolt of the long-stroke gas system helps reliability. I am not sure about the clearances that allow crud to get in as well as out. Would it not be better to have the action tightly sealed up but have internal volume to soak up any debris generated from firing?
It seems to me that the AK is reliable in spite of the gaping holes in the receiver.
It seems to me that the AK is reliable in spite of the gaping holes in the receiver.
jaimeshawn
November 14, 2005, 02:11 AM
(1) A high degree of taper in the case used to be standard for black powder - just check out the taper on the 7.62x54R or the taper on the 30-30 cartridge. Black powder rifles have to be able to deal with crud - which is a lot like the real-world situation with combat rifles being carried by guys that need to stay low. The 7.62x39 cartridge has enourmous amount of taper so it will still fire ammunition coated with dust or mud. The 223 is straight-walled by comparison and efforts to make the bullet diameter larger and use the same case base diameter will make it more straight-walled... One of the highest tapered 'modern' rounds is a 250-3000 Savage, which would make a great intermediate powered round.
(2) The AK has huge bolt lugs fitting into even more enourmous receiver slots, like the MN91/30 and MN44. The bolt lugs make the Garand's look tiny and the M16's look miniscule. My Winchester shotgun tried to copy the tiny bolt lugs idea - and guess what? It jams too!
(3) The AK has a big gas piston throwing a big bolt carrier back. Gas pistons are great because they keep burnt powder crud out of the action. This coupled with the fact that the 7.62x39 carries twice the powder as the .223 leaves more than twice as much energy available to cycle the rifle. Several guys have already mentioned the bolt over-travel and how the bolt, and bolt carrier, have lots of momentum when they strip the next round from the magazine. Big piston/bolt carriers are a good idea!
(4) The basic trigger/hammer/sear is very similar to the Garand. KISS applies here, and the closer you match the basic three component design here without added little parts to do three round bursts or whatever, the more often these parts will work as advertised. The AK47 is a study of the KISS principle.
(5) The big hook directly attached to the bolt carrier means you can hammer it directly BOTH forward and backwards with a big rock, or a tree trunk, or your boot, or whatever... The Garand op rod hook is equally as robust and useful for both forward and reverse assist - and in both cases the last part of the stroke of the bolt carrier 'cams' the bolt into place with huge amounts of mechanical advantage. That way even if you are chambering a shell with a huge chunk of crud on it, you have a good chance of forcing the shell into the chamber and firing it - or tossing it out and inserting another into the chamber.
The AK47 is design of genius - If it had been coupled with a better sectional density cartridge at about 6.5mm and about 50% more power, with decent quality ammo, and good quality barrels, it would have a reputation for accuracy and range as well as reliability...
(2) The AK has huge bolt lugs fitting into even more enourmous receiver slots, like the MN91/30 and MN44. The bolt lugs make the Garand's look tiny and the M16's look miniscule. My Winchester shotgun tried to copy the tiny bolt lugs idea - and guess what? It jams too!
(3) The AK has a big gas piston throwing a big bolt carrier back. Gas pistons are great because they keep burnt powder crud out of the action. This coupled with the fact that the 7.62x39 carries twice the powder as the .223 leaves more than twice as much energy available to cycle the rifle. Several guys have already mentioned the bolt over-travel and how the bolt, and bolt carrier, have lots of momentum when they strip the next round from the magazine. Big piston/bolt carriers are a good idea!
(4) The basic trigger/hammer/sear is very similar to the Garand. KISS applies here, and the closer you match the basic three component design here without added little parts to do three round bursts or whatever, the more often these parts will work as advertised. The AK47 is a study of the KISS principle.
(5) The big hook directly attached to the bolt carrier means you can hammer it directly BOTH forward and backwards with a big rock, or a tree trunk, or your boot, or whatever... The Garand op rod hook is equally as robust and useful for both forward and reverse assist - and in both cases the last part of the stroke of the bolt carrier 'cams' the bolt into place with huge amounts of mechanical advantage. That way even if you are chambering a shell with a huge chunk of crud on it, you have a good chance of forcing the shell into the chamber and firing it - or tossing it out and inserting another into the chamber.
The AK47 is design of genius - If it had been coupled with a better sectional density cartridge at about 6.5mm and about 50% more power, with decent quality ammo, and good quality barrels, it would have a reputation for accuracy and range as well as reliability...
MatthewVanitas
November 14, 2005, 02:24 AM
Great overall summary. On a random sidenote, I've always thought it would have been cool if the Garand had been adopted in .250 Savage. Right up there with the "shoulda" of the EM2 bullpup.
But I do take some issue with your
The AK47 is design of genius - If it had been coupled with a better sectional density cartridge at about 6.5mm and about 50% more power, with decent quality ammo, and good quality barrels, it would have a reputation for accuracy and range as well as reliability...
Okay, the range issue is primarily cartridge-related, so that's doable.
But do you not believe that the AK's overpowered gas system and massive bolt are inconducive to accuracy? Maybe it's a small difference, but the conventional wisdom holds that the "less stuff clunking around" in a direct-impingment system is one of the things that make the AR-15 famously accurate. What thinks? -MV
But I do take some issue with your
The AK47 is design of genius - If it had been coupled with a better sectional density cartridge at about 6.5mm and about 50% more power, with decent quality ammo, and good quality barrels, it would have a reputation for accuracy and range as well as reliability...
Okay, the range issue is primarily cartridge-related, so that's doable.
But do you not believe that the AK's overpowered gas system and massive bolt are inconducive to accuracy? Maybe it's a small difference, but the conventional wisdom holds that the "less stuff clunking around" in a direct-impingment system is one of the things that make the AR-15 famously accurate. What thinks? -MV
Crosshair
November 14, 2005, 02:52 AM
MatthewVanitas
But do you not believe that the AK's overpowered gas system and massive bolt are inconducive to accuracy? Maybe it's a small difference, but the conventional wisdom holds that the "less stuff clunking around" in a direct-impingment system is one of the things that make the AR-15 famously accurate. What thinks? -MV
Good point, but how far has the bolt carrier moved by the time the bullet leaves the barrel. IIRC in the M1 garand, the op rod has only moved 3/8" when the bullet leaves the barrel. I am assuming that something similar happens with the AK. When you pull back the bolt you will see that it moves back a little before it starts to cam the bolt and unlock it from the breech. I would assume that the bolt has not started to unlock until the bullet has left the barrel as the pressures would be too high. So in full auto, the large bolt mass would hurt accuracy, but for single shots it would not be as large an issue, only affecting the speed of followup shots, though not by much. I would have to say that the M-16 design is about as accurate as an AK. However it is FAR easier to make an AR accurate than to do the same to an AK. Ammo quality also must be factored in as well.
In the AR, does the bolt carrier move to the rear a little before unlocking or does it start to cam the bolt as soon as it starts to move?
But do you not believe that the AK's overpowered gas system and massive bolt are inconducive to accuracy? Maybe it's a small difference, but the conventional wisdom holds that the "less stuff clunking around" in a direct-impingment system is one of the things that make the AR-15 famously accurate. What thinks? -MV
Good point, but how far has the bolt carrier moved by the time the bullet leaves the barrel. IIRC in the M1 garand, the op rod has only moved 3/8" when the bullet leaves the barrel. I am assuming that something similar happens with the AK. When you pull back the bolt you will see that it moves back a little before it starts to cam the bolt and unlock it from the breech. I would assume that the bolt has not started to unlock until the bullet has left the barrel as the pressures would be too high. So in full auto, the large bolt mass would hurt accuracy, but for single shots it would not be as large an issue, only affecting the speed of followup shots, though not by much. I would have to say that the M-16 design is about as accurate as an AK. However it is FAR easier to make an AR accurate than to do the same to an AK. Ammo quality also must be factored in as well.
In the AR, does the bolt carrier move to the rear a little before unlocking or does it start to cam the bolt as soon as it starts to move?
Father Knows Best
November 14, 2005, 06:05 AM
(1) A high degree of taper in the case used to be standard for black powder - just check out the taper on the 7.62x54R or the taper on the 30-30 cartridge. Black powder rifles have to be able to deal with crud - which is a lot like the real-world situation with combat rifles being carried by guys that need to stay low.
FYI -- the 30-30 is not and never was a black powder cartridge. It was the first cartridge designed specifically for the then-new (in 1894 or so) smokeless nitro-based propellants.
FYI -- the 30-30 is not and never was a black powder cartridge. It was the first cartridge designed specifically for the then-new (in 1894 or so) smokeless nitro-based propellants.
Dave Markowitz
November 14, 2005, 08:58 AM
But do you not believe that the AK's overpowered gas system and massive bolt are inconducive to accuracy? Maybe it's a small difference, but the conventional wisdom holds that the "less stuff clunking around" in a direct-impingment system is one of the things that make the AR-15 famously accurate. What thinks? -MV
IMO, quality of the barrels and ammo has more to do with a Kalashnikov's accuracy or lack thereof. For example, look at the Robinson Arms Veprs and Arsenal, Inc. milled AKs. Feed either of these rifles good ammo and I think you'll be surprised by their accuracy.
IMO, quality of the barrels and ammo has more to do with a Kalashnikov's accuracy or lack thereof. For example, look at the Robinson Arms Veprs and Arsenal, Inc. milled AKs. Feed either of these rifles good ammo and I think you'll be surprised by their accuracy.
clange
November 14, 2005, 11:56 AM
IMO, quality of the barrels and ammo has more to do with a Kalashnikov's accuracy or lack thereof. For example, look at the Robinson Arms Veprs and Arsenal, Inc. milled AKs. Feed either of these rifles good ammo and I think you'll be surprised by their accuracy.
And toss some optics on it, the AK iron sights are horrible IMO. Adding a red dot to my SAR took my groups from 6-8 inches at 100 yards, to .8 inches at 60-65 yards.
Maybe I just dont know what I'm doing with irons, buts thats a huge difference.
And toss some optics on it, the AK iron sights are horrible IMO. Adding a red dot to my SAR took my groups from 6-8 inches at 100 yards, to .8 inches at 60-65 yards.
Maybe I just dont know what I'm doing with irons, buts thats a huge difference.
Fletchette
November 14, 2005, 02:10 PM
The Robinson XPR is very interesting - I had not paid much attention to it. It seems to combine much of the traits we have been talking about here,
As for AK vs. AR accuracy; it is conventional wisdom that less stuff "clunking around" produces better accuracy. For full-auto I might agree. But for semi-auto, I would think that repeatability is more important, ie: if the AK slams it's heavy bolt into the receiver with the same amount of force, shot-to-shot, then it should be delivering good groups. In practice, this may be more difficult to do. Hence, lowering the reciprocating mass lowers this variability (+ for AR).
As for AK vs. AR accuracy; it is conventional wisdom that less stuff "clunking around" produces better accuracy. For full-auto I might agree. But for semi-auto, I would think that repeatability is more important, ie: if the AK slams it's heavy bolt into the receiver with the same amount of force, shot-to-shot, then it should be delivering good groups. In practice, this may be more difficult to do. Hence, lowering the reciprocating mass lowers this variability (+ for AR).
jaimeshawn
November 14, 2005, 04:58 PM
The Robinson VEPR (AK-type action) is interesting. The photos they published on their website -
http://www.ak47.com/images/target2.jpg
http://www.ak47.com/images/target1.jpg
- look reasonably accurate to me.
http://www.ak47.com/images/target2.jpg
http://www.ak47.com/images/target1.jpg
- look reasonably accurate to me.
Carl N. Brown
November 14, 2005, 05:41 PM
The AK bolt carrier rides on the rails in the receiver and
the piston in the gas cylinder: like the M3 grease gun, the
bolt is designed not to touch the inside of the receiver,
leaving clearance for dirt, sand, fouling, colonies of gnomes,
etc. Now, AKs with close tolerances on the rails and piston
and bolt carrier can be made with precision while allowing the
clearances that keep the AK running while dirty.
The Reising Model 50 had very close tolerances, the bolt
rode against the inside walls of the receiver with no
clearance for dirt, etc., and the Reising failed in combat
conditions.
the piston in the gas cylinder: like the M3 grease gun, the
bolt is designed not to touch the inside of the receiver,
leaving clearance for dirt, sand, fouling, colonies of gnomes,
etc. Now, AKs with close tolerances on the rails and piston
and bolt carrier can be made with precision while allowing the
clearances that keep the AK running while dirty.
The Reising Model 50 had very close tolerances, the bolt
rode against the inside walls of the receiver with no
clearance for dirt, etc., and the Reising failed in combat
conditions.
jaimeshawn
November 15, 2005, 12:16 AM
Wikipedia offers several observations - It looks like AK versions in 223 do not tend to work - so this would argue that the cartridge is the most important thing contributing to reliability - second, the Finnish version in 7.62x39 is supposed to be very accurate which would imply that with decent ammo and barrels, the design is capable of accuracy:
...
The AK-47 is simple and inexpensive to manufacture and very easy to clean and maintain. Its ruggedness and reliability is legendary. The oversized gas piston, generous clearances between moving parts, and tapered cartridge case design allow the gun to endure large amounts of foreign matter and fouling without failing to cycle.
...
Galil in .223: In the beginning of 1990, the newborn Estonian republic purchased some Galil rifles for its army. As result, Estonian soldiers considered them very unreliable and stated that they can`t even be compared with AK rifles as the weapons became useless in very little change of temperature, also small amount of sand and dirt made arms malfunction.
The weapon never caught on among Israel's numerous special forces units, who used AK-47's both for reliability, and because of the Galil's cumbersome weight.
....
INSAS in .223: Although largely based on the ever popular AK-47 Rifles, the INSAS has a number of differences making it a unique rifle. It has features and design borrowed from the FN FNC AK-74 the Galil and G3 In assault rifle version it has semi-auto and 3-round burst modes much like the US M1A2 assault rifles. .... The INSAS rifle saw combat with Indian soldiers during the 1999 Kargil conflict with Pakistan, Quoting the Times of India newspaper, the rifle had some reliability problems
...
Accuracy of Finnish Version in 7.62x39: The Rk 62 is considered a very high quality AK-47 clone and this is apparent especially in its accuracy and it can in many cases achieve less than one minute of arc.
...
The AK-47 is simple and inexpensive to manufacture and very easy to clean and maintain. Its ruggedness and reliability is legendary. The oversized gas piston, generous clearances between moving parts, and tapered cartridge case design allow the gun to endure large amounts of foreign matter and fouling without failing to cycle.
...
Galil in .223: In the beginning of 1990, the newborn Estonian republic purchased some Galil rifles for its army. As result, Estonian soldiers considered them very unreliable and stated that they can`t even be compared with AK rifles as the weapons became useless in very little change of temperature, also small amount of sand and dirt made arms malfunction.
The weapon never caught on among Israel's numerous special forces units, who used AK-47's both for reliability, and because of the Galil's cumbersome weight.
....
INSAS in .223: Although largely based on the ever popular AK-47 Rifles, the INSAS has a number of differences making it a unique rifle. It has features and design borrowed from the FN FNC AK-74 the Galil and G3 In assault rifle version it has semi-auto and 3-round burst modes much like the US M1A2 assault rifles. .... The INSAS rifle saw combat with Indian soldiers during the 1999 Kargil conflict with Pakistan, Quoting the Times of India newspaper, the rifle had some reliability problems
...
Accuracy of Finnish Version in 7.62x39: The Rk 62 is considered a very high quality AK-47 clone and this is apparent especially in its accuracy and it can in many cases achieve less than one minute of arc.
clange
November 15, 2005, 12:52 AM
It looks like AK versions in 223 do not tend to work [/b]
Two weapon systems having problems hardly means .223 AKs dont work.
Bulgarian 5.56 rifles dont have any problems AFAIK. I'd be willing to bet the AK-101, 102, and 108 from russia are reliable as well.
Maybe torture tests would show these to be less reliable than their 47/74 counterparts, but I havent heard anything like that yet.
Two weapon systems having problems hardly means .223 AKs dont work.
Bulgarian 5.56 rifles dont have any problems AFAIK. I'd be willing to bet the AK-101, 102, and 108 from russia are reliable as well.
Maybe torture tests would show these to be less reliable than their 47/74 counterparts, but I havent heard anything like that yet.
Fletchette
November 15, 2005, 01:13 PM
Assuming that the cartridge has a large affect on reliability, what could be done to the rifle to make it more reliable? Stated another way: if you MUST use .223/5.56, what can you do to make your rifle feed reliably?
AZ Jeff
November 15, 2005, 02:31 PM
Arguing over semantics again.
Yes, we are. But it's those two words, and their differences, are an IMPORTANT distinction to an engineer or manufacturing person.
It's kind of like the terms "magazine" and "clip", and Lord know how many times that discussion has surfaced on this forum.
Yes, we are. But it's those two words, and their differences, are an IMPORTANT distinction to an engineer or manufacturing person.
It's kind of like the terms "magazine" and "clip", and Lord know how many times that discussion has surfaced on this forum.
AZ Jeff
November 15, 2005, 03:14 PM
But do you not believe that the AK's overpowered gas system and massive bolt are inconducive to accuracy? Maybe it's a small difference, but the conventional wisdom holds that the "less stuff clunking around" in a direct-impingment system is one of the things that make the AR-15 famously accurate. What thinks? -MV
Good point, but how far has the bolt carrier moved by the time the bullet leaves the barrel. IIRC in the M1 garand, the op rod has only moved 3/8" when the bullet leaves the barrel. I am assuming that something similar happens with the AK. When you pull back the bolt you will see that it moves back a little before it starts to cam the bolt and unlock it from the breech. I would assume that the bolt has not started to unlock until the bullet has left the barrel as the pressures would be too high. So in full auto, the large bolt mass would hurt accuracy, but for single shots it would not be as large an issue, only affecting the speed of followup shots, though not by much. I would have to say that the M-16 design is about as accurate as an AK. However it is FAR easier to make an AR accurate than to do the same to an AK. Ammo quality also must be factored in as well.
In theory, your argument makes sense. In practice, though, it's proven to not be the case. Rifles with long receivers (and bolt bounce, like the AK is known for) tend to show inferior accuracy, even on semi-auto fire, to the competitors lacking these characteristics.
Good point, but how far has the bolt carrier moved by the time the bullet leaves the barrel. IIRC in the M1 garand, the op rod has only moved 3/8" when the bullet leaves the barrel. I am assuming that something similar happens with the AK. When you pull back the bolt you will see that it moves back a little before it starts to cam the bolt and unlock it from the breech. I would assume that the bolt has not started to unlock until the bullet has left the barrel as the pressures would be too high. So in full auto, the large bolt mass would hurt accuracy, but for single shots it would not be as large an issue, only affecting the speed of followup shots, though not by much. I would have to say that the M-16 design is about as accurate as an AK. However it is FAR easier to make an AR accurate than to do the same to an AK. Ammo quality also must be factored in as well.
In theory, your argument makes sense. In practice, though, it's proven to not be the case. Rifles with long receivers (and bolt bounce, like the AK is known for) tend to show inferior accuracy, even on semi-auto fire, to the competitors lacking these characteristics.
jaimeshawn
November 15, 2005, 05:47 PM
To answer Fletchete:
A number of weapons are reliable with relatively straight walled rifle cases like 7.62x51 NATO, 30-06, 8mm Mauser so it _could_ be possible to do the same with a 5.56x45 NATO, although those other cartridges have quite a bit more energy that can be used to cycle the weapon.
Smaller cartridges like 9mm Luger have successfully been used in reliable subguns – and that’s probably where I would look for a design to copy for the 223. Maybe even go with a blow-back Sten or Stirling-type design, although the Stens were not especially known for reliability – most of the blame usually falls on their crappy magazines. The M1 Thompson SMG is also blow-back design and highly prized by the GIs, and I think the UZI, which the Israelis liked, may be as well... The 5.56 NATO does have a disadvantage against the 9mm Luger in that the 223 case length is a lot longer and the stiction would be much worse of a problem of extracting while the chamber pressure is high. Maybe an over-sized, tapered and fluted chamber to the point of clover-leafing brass with a heavy non-locking bolt – lots of bolt over-travel, and a fairly robust cocking/assist knob attached to the bolt so it can be beaten into submission both directions. The fluting would be for crud to have someplace to go when chambering and to keep the case from sticking to the chamber as it is ripped clear.
What do you think?
A number of weapons are reliable with relatively straight walled rifle cases like 7.62x51 NATO, 30-06, 8mm Mauser so it _could_ be possible to do the same with a 5.56x45 NATO, although those other cartridges have quite a bit more energy that can be used to cycle the weapon.
Smaller cartridges like 9mm Luger have successfully been used in reliable subguns – and that’s probably where I would look for a design to copy for the 223. Maybe even go with a blow-back Sten or Stirling-type design, although the Stens were not especially known for reliability – most of the blame usually falls on their crappy magazines. The M1 Thompson SMG is also blow-back design and highly prized by the GIs, and I think the UZI, which the Israelis liked, may be as well... The 5.56 NATO does have a disadvantage against the 9mm Luger in that the 223 case length is a lot longer and the stiction would be much worse of a problem of extracting while the chamber pressure is high. Maybe an over-sized, tapered and fluted chamber to the point of clover-leafing brass with a heavy non-locking bolt – lots of bolt over-travel, and a fairly robust cocking/assist knob attached to the bolt so it can be beaten into submission both directions. The fluting would be for crud to have someplace to go when chambering and to keep the case from sticking to the chamber as it is ripped clear.
What do you think?
Fletchette
November 15, 2005, 08:25 PM
Jaimeshawn,
Fluting the chamber might actually have an advantage for use in the field as a crud escape route. I have had some .223 rifles without fluting that needed "help" in chambering a round after a few hundred shots, so I know that fouling build up can affect this cartidge.
The sticktion could be handled in one or a combination of two ways:
1) The use a long-stroke piston cycle. This adds mass to the boltcarrier and also has gas actively pushing the bolt back for a longer distance than a short-stroke gas system. Combine this with bolt over-travel and you increase the likelyhood of chambering due to the extra velocity the bolt has to strip a round from the magazine. Of course, all of this makes for a lot of mass clunking around - inaccuracy. This is what the AK did.
2) Use a plenum chamber in the gas cylinder to draw high pressure gas earlier in the cycle (the port is closer to the chamber). This plenum would smooth out the otherwise short and high pressure spike that is delivered to the bolt carrier. With a plenum, the pressure would build much more gradually and push for a longer duration than direct impingement. As a nice bonus, it does not require a lot of mass cluncking around. Hey, how come no one has done this?
Fluting the chamber might actually have an advantage for use in the field as a crud escape route. I have had some .223 rifles without fluting that needed "help" in chambering a round after a few hundred shots, so I know that fouling build up can affect this cartidge.
The sticktion could be handled in one or a combination of two ways:
1) The use a long-stroke piston cycle. This adds mass to the boltcarrier and also has gas actively pushing the bolt back for a longer distance than a short-stroke gas system. Combine this with bolt over-travel and you increase the likelyhood of chambering due to the extra velocity the bolt has to strip a round from the magazine. Of course, all of this makes for a lot of mass clunking around - inaccuracy. This is what the AK did.
2) Use a plenum chamber in the gas cylinder to draw high pressure gas earlier in the cycle (the port is closer to the chamber). This plenum would smooth out the otherwise short and high pressure spike that is delivered to the bolt carrier. With a plenum, the pressure would build much more gradually and push for a longer duration than direct impingement. As a nice bonus, it does not require a lot of mass cluncking around. Hey, how come no one has done this?
beerslurpy
November 15, 2005, 08:51 PM
Wikipedia offers several observations -
The oversized gas piston, generous clearances between moving parts, and tapered cartridge case design allow the gun to endure large amounts of foreign matter and fouling without failing to cycle.
I've been quoted!
The oversized gas piston, generous clearances between moving parts, and tapered cartridge case design allow the gun to endure large amounts of foreign matter and fouling without failing to cycle.
I've been quoted!
benEzra
November 17, 2005, 11:41 AM
Good point, but how far has the bolt carrier moved by the time the bullet leaves the barrel. IIRC in the M1 garand, the op rod has only moved 3/8" when the bullet leaves the barrel. I am assuming that something similar happens with the AK.
As soon as the gas impinges on the piston (e.g., while the bullet is still in the barrel), there will be large barrel bending moments from the off-axis torque on the barrel, and the gun itself may start to move as well. Remember, practically ALL the acceleration of the bolt carrier occurs in the first half-inch of movement (after that, it's just coasting and exerting negligible force on the rifle, until it starts loading up the recoil spring toward the rear of its travel).
I don't know how significant its effects would be on the bullet's trajectory, especially with a 16.5" barrelled AK, but I know the mini-14 has similiar difficulties with accuracy, and it has a similar gas system (though the piston is turned inside out). I have found that my SAR-1 is very sensitive to being benchrested; if I put the bag very far forward, POI seems to shift a great deal compared to a sandbag just forward of the magazine. My thought was that the rifle is jumping off the bag as it flexes during bolt carrier acceleration, but without a high-speed camera there's no way to know.
I think the lousy sights have a lot more to do with it, though.
As soon as the gas impinges on the piston (e.g., while the bullet is still in the barrel), there will be large barrel bending moments from the off-axis torque on the barrel, and the gun itself may start to move as well. Remember, practically ALL the acceleration of the bolt carrier occurs in the first half-inch of movement (after that, it's just coasting and exerting negligible force on the rifle, until it starts loading up the recoil spring toward the rear of its travel).
I don't know how significant its effects would be on the bullet's trajectory, especially with a 16.5" barrelled AK, but I know the mini-14 has similiar difficulties with accuracy, and it has a similar gas system (though the piston is turned inside out). I have found that my SAR-1 is very sensitive to being benchrested; if I put the bag very far forward, POI seems to shift a great deal compared to a sandbag just forward of the magazine. My thought was that the rifle is jumping off the bag as it flexes during bolt carrier acceleration, but without a high-speed camera there's no way to know.
I think the lousy sights have a lot more to do with it, though.
oldfart
November 17, 2005, 12:10 PM
Tolerance-- Clearance-- whatever...
The primary reason the AK is so reliable is the lack of parts to bend, break or blow up! I look at the AK parts list in the Numrich catalog and find a grand total of 81 parts. When I turn to the Colt AR15/M16 listing I find eight pages of parts!
I don't think anyone will argue that the Ak is as accurate as the AR but it is a whole lot less likely to jam. Basically, our military "minds" traded reliability for accuracy. Unfortunately, they threw out effectiveness in the process, leaving our soldietrs with a round that just doesn't hit hard enough to put down a doped-up suicide bomber.
JMHO. YMMV.
The primary reason the AK is so reliable is the lack of parts to bend, break or blow up! I look at the AK parts list in the Numrich catalog and find a grand total of 81 parts. When I turn to the Colt AR15/M16 listing I find eight pages of parts!
I don't think anyone will argue that the Ak is as accurate as the AR but it is a whole lot less likely to jam. Basically, our military "minds" traded reliability for accuracy. Unfortunately, they threw out effectiveness in the process, leaving our soldietrs with a round that just doesn't hit hard enough to put down a doped-up suicide bomber.
JMHO. YMMV.
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