romulus
Member
ahhh...of course, the gap between ramp and barrel will increase. I can fit a piece of a business card in there and still cycle the gun without compressing the card (a Norinco) Having said that, I never had a failure to feed...
1911 Clinic. The barrel link
- Thread starter bigjim
- Start date
- Status
1911Tuner
Moderator Emeritus
The Gap
Romulus said:
) Having said that, I never had a failure to feed...
Hey..If it ain't broke, don't fix it I always say.
Romulus said:
) Having said that, I never had a failure to feed...
Hey..If it ain't broke, don't fix it I always say.
romulus
Member
Yes indeed. Nonetheless, I always strive to understand the theory, the reason behind things, not just the effect. So I learned a valuable lesson. Thank you.
My oh my! Tell ya what, guys-if Delmar ever wins the lottery, several of you are going to get seriously PM'ed to form a company to build 1911's the RIGHT way.
There is no doubt in my mind that there are enough people on this forum with the knowhow to build a 45 so correct that the custom builders would be scrambling to compete!
Yeah, I know-its probably not going to stay solvent for long. Sort of taking a large fortune and turning it into a small one
Heck-nobody lives forever!
There is no doubt in my mind that there are enough people on this forum with the knowhow to build a 45 so correct that the custom builders would be scrambling to compete!
Yeah, I know-its probably not going to stay solvent for long. Sort of taking a large fortune and turning it into a small one
Heck-nobody lives forever!Jammer Six
member
If I understand what you guys are saying, match pistol "wedge" (my understanding) themselves into vertical lockup using the profile of the two feet of the barrel lug bearing on the slide stop pin. This is more stable, tighter, and more predictable than riding the link, which must be looser and allows the barrel to "wobble".
Carry weapons, on the other hand, ride the link.
You guys didn't say anything about why, but I've been thinking about it.
It sounds to me like this: if any goo, gunk or grit got into the lugs or onto the slide stop pin, if the fit was real tight, it could be enough to prevent the barrel from wedging into place, and stop the weapon from going into battery.
Is that the reason carry weapons aren't fit to ride the lugs?
Jim, I haven't found your vector theory in Kuhnhausen. Where is it?
Carry weapons, on the other hand, ride the link.
You guys didn't say anything about why, but I've been thinking about it.
It sounds to me like this: if any goo, gunk or grit got into the lugs or onto the slide stop pin, if the fit was real tight, it could be enough to prevent the barrel from wedging into place, and stop the weapon from going into battery.
Is that the reason carry weapons aren't fit to ride the lugs?
Jim, I haven't found your vector theory in Kuhnhausen. Where is it?
1911Tuner
Moderator Emeritus
Riding the Link
Jammer asked:
It sounds to me like this: if any goo, gunk or grit got into the lugs or onto the slide stop pin, if the fit was real tight, it could be enough to prevent the barrel from wedging into place, and stop the weapon from going into battery.
Yep. A tightly-fitted match-grade pistol is more sensitive to dirt. Accuracy
comes with a price, and reliability under adverse conditions is the cost.
Bullseye pistols are the most tightly fitted. Action-game guns are a little
less so, and are less dirt sensitive. Defensive pistols, or pistols built to
save the life of a Marine on Saipan or an Airborne Ranger on Omaha
Beach are the loosest.
It's entirely possible to have a good lower lug to pin fit without
sacrificing reliability, it just won't deliver match-grade accuracy.
I have a few carry pistols and range beaters that have zero vertical
movement at the hood, but will run through over 2,000 rounds reliably
without cleaning. The main thing is to get the pin to bear evenly on both
lugs. If there's a tiny bit of vertical play, the pistol will be accurate enough
for its intended use. As long as the firing pin strike is well-centered, it
won't really hurt anything other than causing the pistol to shoot a little high.
There are also other factors that determine accuracy. Hood to slide fit
to limit barrel rotation. Locking lug fit to the recesses and lugs in the slide
to limit fore and aft play in the barrel. Bushing to slide and barrel to bushing fit. Headspacing and barrel crown...All these add up to create
accuracy, or degrade it, as the case may be. Slide to frame fit seems to have the least effect on accuracy or the lack of it, unless the pistol is
mounted in a machine rest.
Cheers!
Tuner
Jammer asked:
It sounds to me like this: if any goo, gunk or grit got into the lugs or onto the slide stop pin, if the fit was real tight, it could be enough to prevent the barrel from wedging into place, and stop the weapon from going into battery.
Yep. A tightly-fitted match-grade pistol is more sensitive to dirt. Accuracy
comes with a price, and reliability under adverse conditions is the cost.
Bullseye pistols are the most tightly fitted. Action-game guns are a little
less so, and are less dirt sensitive. Defensive pistols, or pistols built to
save the life of a Marine on Saipan or an Airborne Ranger on Omaha
Beach are the loosest.
It's entirely possible to have a good lower lug to pin fit without
sacrificing reliability, it just won't deliver match-grade accuracy.
I have a few carry pistols and range beaters that have zero vertical
movement at the hood, but will run through over 2,000 rounds reliably
without cleaning. The main thing is to get the pin to bear evenly on both
lugs. If there's a tiny bit of vertical play, the pistol will be accurate enough
for its intended use. As long as the firing pin strike is well-centered, it
won't really hurt anything other than causing the pistol to shoot a little high.
There are also other factors that determine accuracy. Hood to slide fit
to limit barrel rotation. Locking lug fit to the recesses and lugs in the slide
to limit fore and aft play in the barrel. Bushing to slide and barrel to bushing fit. Headspacing and barrel crown...All these add up to create
accuracy, or degrade it, as the case may be. Slide to frame fit seems to have the least effect on accuracy or the lack of it, unless the pistol is
mounted in a machine rest.
Cheers!
Tuner
BigJim:
In the past those who built Colt Government Model pistols at the factory served as apprentices working under master “smith’s†supervision. The skill of these workers was such that when the Springfield Arsenal wanted to produce the pistol Colt couldn’t provide a full set of drawings – because they didn’t have any! They didn’t need them “in-house†because their workers used a combination of skill, experience and gages. In the end the engineers at the arsenal disassembled a number of Colt-manufactured guns, measured the parts, averaged the important dimensions, and over a period of about a year made their own drawings. The young (and carefully chosen) apprentices didn’t start out doing perfect work, but they also didn’t do any work on commercial or government products without being carefully watched and checked – and it was sometimes years before they started doing work on their own.
During the late 1950’s and forward the military services trained individuals to build match rifles and pistols as part of a larger Marksmanship Training Program. Many of these men would later play a large part in building guns for the various “Combat†games that became popular as well as producing true weapons. Again they were the product of a system that produced what might be called “gun-makers with a formal background.†A smaller number learned their trade by attending schools with gunsmithing programs.
All of these examples shared at least one common thread. They were in one way or another, trained to do the work they did, and sometimes spent years in the learning process.
Tuner:
The Old Fuff is indeed famous, but only in his own ego.
In the past those who built Colt Government Model pistols at the factory served as apprentices working under master “smith’s†supervision. The skill of these workers was such that when the Springfield Arsenal wanted to produce the pistol Colt couldn’t provide a full set of drawings – because they didn’t have any! They didn’t need them “in-house†because their workers used a combination of skill, experience and gages. In the end the engineers at the arsenal disassembled a number of Colt-manufactured guns, measured the parts, averaged the important dimensions, and over a period of about a year made their own drawings. The young (and carefully chosen) apprentices didn’t start out doing perfect work, but they also didn’t do any work on commercial or government products without being carefully watched and checked – and it was sometimes years before they started doing work on their own.
During the late 1950’s and forward the military services trained individuals to build match rifles and pistols as part of a larger Marksmanship Training Program. Many of these men would later play a large part in building guns for the various “Combat†games that became popular as well as producing true weapons. Again they were the product of a system that produced what might be called “gun-makers with a formal background.†A smaller number learned their trade by attending schools with gunsmithing programs.
All of these examples shared at least one common thread. They were in one way or another, trained to do the work they did, and sometimes spent years in the learning process.
Tuner:
The Old Fuff is indeed famous, but only in his own ego.
1911Tuner
Moderator Emeritus
Kunhausen's Thrust Vector
Jammer, here is a good link with pictures that describes what Jim is talking about. The pictures will take a few minutes to download, and a few points
aren't accurately illustrated, but it's still a good visual aid.
http://www.m1911.org/locking.htm
bigjim asked:
If you take a 1911 pistol and shoot it by hand or shoot from a ransom rest, which method will produce a better group?
I know on the surface this seems like a dumb question. But I suspect there is more to it than may meet the eye.
Depending on a few things, it's entirely possible to shoot a tighter group
without the machine rest. I'll have to get deeper into it in the mornin'...
Beddy-bye time. Been a long stretch since 3 this A. M.
One hint: If the barrel is fitted well to the slide, but the slide to frame fit
is loose, a good marksman can outshoot the pistol fired from a Ransom rest.
Think about it. See the gun. BE... the gun, and it will come to you.
Nitey-nite!
Tuner
Jammer, here is a good link with pictures that describes what Jim is talking about. The pictures will take a few minutes to download, and a few points
aren't accurately illustrated, but it's still a good visual aid.
http://www.m1911.org/locking.htm
bigjim asked:
If you take a 1911 pistol and shoot it by hand or shoot from a ransom rest, which method will produce a better group?
I know on the surface this seems like a dumb question. But I suspect there is more to it than may meet the eye.
Depending on a few things, it's entirely possible to shoot a tighter group
without the machine rest. I'll have to get deeper into it in the mornin'...
Beddy-bye time. Been a long stretch since 3 this A. M.
One hint: If the barrel is fitted well to the slide, but the slide to frame fit
is loose, a good marksman can outshoot the pistol fired from a Ransom rest.
Think about it. See the gun. BE... the gun, and it will come to you.
Nitey-nite!
Tuner
Last edited:
Jammer:
The answer to your question isn’t easy because so many companies – as well as individuals – are making Colt style pistols. Each uses one or more methods of fitting a barrel, and we haven’t discussed all of the possibilities, just the popular ones. Many employ the word “combat†to the point where it has become meaningless. Thus you have so-called “combat guns†that have match-fitted barrels that are set up to lock by being cammed by the slide stop pin and lower barrel lug. So what happens if too much dirt and fouling gets into a critical area? Well unless the gun maker/builder has taken this into account and built in some clearance the pistol will probably jam – just as you suggested. This is one reason that today’s buyers expect to fire several hundred rounds through a gun to “break it in†before it’s really reliable (?) when in earlier years this wasn’t necessary.
However, if a pistol that uses the camming system is correctly adjusted to take fouling into consideration you have the best of all worlds.
Unfortunately only a few companies/people who are involved in making guns understand what is truly necessary to make a weapon rather then a toy.
The answer to your question isn’t easy because so many companies – as well as individuals – are making Colt style pistols. Each uses one or more methods of fitting a barrel, and we haven’t discussed all of the possibilities, just the popular ones. Many employ the word “combat†to the point where it has become meaningless. Thus you have so-called “combat guns†that have match-fitted barrels that are set up to lock by being cammed by the slide stop pin and lower barrel lug. So what happens if too much dirt and fouling gets into a critical area? Well unless the gun maker/builder has taken this into account and built in some clearance the pistol will probably jam – just as you suggested. This is one reason that today’s buyers expect to fire several hundred rounds through a gun to “break it in†before it’s really reliable (?) when in earlier years this wasn’t necessary.
However, if a pistol that uses the camming system is correctly adjusted to take fouling into consideration you have the best of all worlds.
Unfortunately only a few companies/people who are involved in making guns understand what is truly necessary to make a weapon rather then a toy.
1911Tuner
Moderator Emeritus
Toy Guns/Real Guns
Amen and amen. In his usual fashion, Fuff has cut through the BS and headed straight for the heart of the matter. Sadly, the manufacturers of the 1911 pattern pistol know that, for the most part, they're building a toy. Many of them set the guns up far too tight to be serious weaponry. Whenever I hear of a warranty station telling an unhappy customer to shoot a thousand rounds to "break it in", I shrug my shoulders.
They do this for three reasons, as far as I can determine...none of which
is valid for a pistol that is to be used as a weapon.
1...The customer believes that a super tight pistol is a better pistol. I
think this stems from the complaints coming from the flood of GI pistols
that began showing up. Worn out, poorly rebuilt...many of them were
parts guns that were slapped together and pawned off as "genuine".
2...To wring maximum accuracy from the guns...which may or may not work, again depending on the skill of the builder or the QC of the manufacturer.
Again, complaints about the "innacuracy" of the .45s is to blame. The
plain truth is that a true ordnance-spec pistol isn't a loose rattle bucket.
I've had the privelege of handling a few pre-war 1911s and 1911-A1s
that were in pristine condition. There was very little play in the slide to
frame fit. No vertical barrel play...Barely enough fore and aft or
rotational movement in the barrel to be able to detect, and the barrel to bushing clearance was .003 inch or less. The pistols were accurate and completely reliable. Military and commercial Colts were all built the same
way, by the same people.
During the watershed of WW2, it was determined by engineers that some of the tolerances could be loosened up an little without compromising the
functional reliability of the guns, and it became standard. This wasn't done
to make them less jam-prone in adverse conditions...It was to speed up
production, and to allow "Rosie the Riveter" workers to assemble guns that were needed in a hurry. The "Drop-In" part was born.
3...Because the US Government hasn't accepted any contracts for the pistol since 1945, and the reliability of the pistols isn't all that critical
any more. Colt built post-war commercial models for a while from the
parts left over from the GI era...but those are long since gone. They
continued to build them using the same correct materials for a while longer, but as the cost of production escalated, profit margins began to dictate how the pistols would be built. Investment cast, and later, MIM small parts began to surface. Small parts were no longer made in-house, but contracted to outside vendors. "Your equipment was supplied by the
lowest bidder." So sayeth Gunny.
Enter the Custom Pistolsmith. He will build to your specifications. He is
the bastion of days past. He will build it "Right, not Tight" for those who
understand...or he will build it dead tight, as you wish. This is why the
really good ones spend time discussing your pistol order. They ask
pointed questions to determine what it will be used for. Strictly target
or defense/carry...and then build it the best way for the intended role.
Some few will build them all tight, and advise you to break them in.
Okay...but there is a simple and effective method of speeding up the
break-in process on a pistol that's too tight.
Jim Keenan and I understand. Jim is a pistolsmith, while I am more of
an expedient field armorer...a troubleshooter and repairman. I'm
beginning to feel that Old Fuff is the sleeper of the group. He understands too, and I think he knows more than he's revealing so far. No doubt that he and Keenan would smoke me in a Custom Pistol contest. 90% of my experience has been salvaging, rebuilding, troubleshooting, and repair. Got a functional problem? I'm your boy. Want to talk about custom building or accuracy tweaking? I have to defer to those two.
Amen and amen. In his usual fashion, Fuff has cut through the BS and headed straight for the heart of the matter. Sadly, the manufacturers of the 1911 pattern pistol know that, for the most part, they're building a toy. Many of them set the guns up far too tight to be serious weaponry. Whenever I hear of a warranty station telling an unhappy customer to shoot a thousand rounds to "break it in", I shrug my shoulders.
They do this for three reasons, as far as I can determine...none of which
is valid for a pistol that is to be used as a weapon.
1...The customer believes that a super tight pistol is a better pistol. I
think this stems from the complaints coming from the flood of GI pistols
that began showing up. Worn out, poorly rebuilt...many of them were
parts guns that were slapped together and pawned off as "genuine".
2...To wring maximum accuracy from the guns...which may or may not work, again depending on the skill of the builder or the QC of the manufacturer.
Again, complaints about the "innacuracy" of the .45s is to blame. The
plain truth is that a true ordnance-spec pistol isn't a loose rattle bucket.
I've had the privelege of handling a few pre-war 1911s and 1911-A1s
that were in pristine condition. There was very little play in the slide to
frame fit. No vertical barrel play...Barely enough fore and aft or
rotational movement in the barrel to be able to detect, and the barrel to bushing clearance was .003 inch or less. The pistols were accurate and completely reliable. Military and commercial Colts were all built the same
way, by the same people.
During the watershed of WW2, it was determined by engineers that some of the tolerances could be loosened up an little without compromising the
functional reliability of the guns, and it became standard. This wasn't done
to make them less jam-prone in adverse conditions...It was to speed up
production, and to allow "Rosie the Riveter" workers to assemble guns that were needed in a hurry. The "Drop-In" part was born.
3...Because the US Government hasn't accepted any contracts for the pistol since 1945, and the reliability of the pistols isn't all that critical
any more. Colt built post-war commercial models for a while from the
parts left over from the GI era...but those are long since gone. They
continued to build them using the same correct materials for a while longer, but as the cost of production escalated, profit margins began to dictate how the pistols would be built. Investment cast, and later, MIM small parts began to surface. Small parts were no longer made in-house, but contracted to outside vendors. "Your equipment was supplied by the
lowest bidder." So sayeth Gunny.
Enter the Custom Pistolsmith. He will build to your specifications. He is
the bastion of days past. He will build it "Right, not Tight" for those who
understand...or he will build it dead tight, as you wish. This is why the
really good ones spend time discussing your pistol order. They ask
pointed questions to determine what it will be used for. Strictly target
or defense/carry...and then build it the best way for the intended role.
Some few will build them all tight, and advise you to break them in.
Okay...but there is a simple and effective method of speeding up the
break-in process on a pistol that's too tight.
Jim Keenan and I understand. Jim is a pistolsmith, while I am more of
an expedient field armorer...a troubleshooter and repairman. I'm
beginning to feel that Old Fuff is the sleeper of the group. He understands too, and I think he knows more than he's revealing so far. No doubt that he and Keenan would smoke me in a Custom Pistol contest. 90% of my experience has been salvaging, rebuilding, troubleshooting, and repair. Got a functional problem? I'm your boy. Want to talk about custom building or accuracy tweaking? I have to defer to those two.
Hi, Jammer Six,
It's not "my" "thrust vector" theory, it is Kuhnhausen's. I don't have the books at hand right now but it is in the section where he shows the operation of the pistol and the drawing depicts the bullet exiting the barrel while it is in full lockup and the link is still fully forward. He says that the barrel doesn't move until the bullet exits and attributes this to a "thrust vector". He is not a physicist and I suspect he simply couldn't handle the concept of recoil.
I like the books, and use them frequently. They are excellent works on tuning and maintaining the 1911 type pistol. But it would be nice if he understood how the darned gun works.
Hi, 1911tuner,
Thanks for the kind words. But unlike some of the folks here, I have not devoted my time exclusively to the 1911, just working on them as part of the work of a general gunsmith. But I did learn what makes the gun tick (see above on another JK) and turned out a few very nice ones, or at least I had the customers fooled.
Jim
It's not "my" "thrust vector" theory, it is Kuhnhausen's. I don't have the books at hand right now but it is in the section where he shows the operation of the pistol and the drawing depicts the bullet exiting the barrel while it is in full lockup and the link is still fully forward. He says that the barrel doesn't move until the bullet exits and attributes this to a "thrust vector". He is not a physicist and I suspect he simply couldn't handle the concept of recoil.
I like the books, and use them frequently. They are excellent works on tuning and maintaining the 1911 type pistol. But it would be nice if he understood how the darned gun works.
Hi, 1911tuner,
Thanks for the kind words. But unlike some of the folks here, I have not devoted my time exclusively to the 1911, just working on them as part of the work of a general gunsmith. But I did learn what makes the gun tick (see above on another JK) and turned out a few very nice ones, or at least I had the customers fooled.
Jim
1911Tuner
Moderator Emeritus
Jammer's Questions
Howdy Jim. I think you're bein' modest.
Jammer isn't tryin' to box you in on the Thrust Vector thing. He's just tryin' to find it. He and I have been working on a hammer followdown issue that he had after a hack polished everything before he got the gun. From what he tells me, he's got it fixed, and is on a search for more knowledge.
Jammer, if you didn't see the link that I pasted to an earlier post, I'll
redo it so you can open the page. Good cutaway view of the pistol,
though some of the pictures aren't completely accurate, and a description
of the Thrust vector that Jim is referring to. I'll go get it and put it at the bottom of this reply on an edit. The pictures take a few minutes to
download, so be patient.
Pay particular attention to the picture and description of the link's function, and look closely at the picture in Locking Phase A. It shows a properly fitted link in relation to the front radius of the barrel lug. Here, it appears that the barrel is lightly riding the link, and pivoting upward on it, though part of the load is also borne by the lug itself. This is the point that Jim and I had a heated discussion over about a year ago. He was talking about a fitted barrel lug, and I was talking about an Ordnance setup. When we realized that we were comparing apples to oranges, we arrived at a Modus Vivendi, and have had many discussions via E-mail ever since.
Most production pistols ride the link much more than is shown, until full
lockup, at which point the link is flush..or nearly so...with the bottom of the
lug as shown in the next frame. It can be slightly below flush, but it shouldn't be ABOVE flush. Some are very slightly above flush, and I think that this is what Fuff is referring to as the viable link-borne lockup. I'd
assign a maximum of .003 inch above flush, but would prefer that it be
dead on if it can be arranged. At any rate, below flush is preferable in order to prevent putting undue stress on the link and pin. The link-borne
lockup doesn't seem to hurt anything in the short term, but on a heavy
use pistol, it can cause some problems.
If I have a situation where I can't find a link to make me happy, I'm not above elongating the hole slightly to get the fit that I want. Again, .003 inch maximum for this kind of "Jerk Engineering" ..and always at the top of the hole. Removing metal from the bottom will delay linkdown timing. At any rate, the desideratum is to match the link to the lug's radii whenever possible. The other route is to weld and re-cut the lug...a tedious undertaking, and not one for the inexperienced.
http://www.m1911.org/locking.htm
Cheers!
Tuner
Howdy Jim. I think you're bein' modest.
Jammer isn't tryin' to box you in on the Thrust Vector thing. He's just tryin' to find it. He and I have been working on a hammer followdown issue that he had after a hack polished everything before he got the gun. From what he tells me, he's got it fixed, and is on a search for more knowledge.
Jammer, if you didn't see the link that I pasted to an earlier post, I'll
redo it so you can open the page. Good cutaway view of the pistol,
though some of the pictures aren't completely accurate, and a description
of the Thrust vector that Jim is referring to. I'll go get it and put it at the bottom of this reply on an edit. The pictures take a few minutes to
download, so be patient.
Pay particular attention to the picture and description of the link's function, and look closely at the picture in Locking Phase A. It shows a properly fitted link in relation to the front radius of the barrel lug. Here, it appears that the barrel is lightly riding the link, and pivoting upward on it, though part of the load is also borne by the lug itself. This is the point that Jim and I had a heated discussion over about a year ago. He was talking about a fitted barrel lug, and I was talking about an Ordnance setup. When we realized that we were comparing apples to oranges, we arrived at a Modus Vivendi, and have had many discussions via E-mail ever since.
Most production pistols ride the link much more than is shown, until full
lockup, at which point the link is flush..or nearly so...with the bottom of the
lug as shown in the next frame. It can be slightly below flush, but it shouldn't be ABOVE flush. Some are very slightly above flush, and I think that this is what Fuff is referring to as the viable link-borne lockup. I'd
assign a maximum of .003 inch above flush, but would prefer that it be
dead on if it can be arranged. At any rate, below flush is preferable in order to prevent putting undue stress on the link and pin. The link-borne
lockup doesn't seem to hurt anything in the short term, but on a heavy
use pistol, it can cause some problems.
If I have a situation where I can't find a link to make me happy, I'm not above elongating the hole slightly to get the fit that I want. Again, .003 inch maximum for this kind of "Jerk Engineering" ..and always at the top of the hole. Removing metal from the bottom will delay linkdown timing. At any rate, the desideratum is to match the link to the lug's radii whenever possible. The other route is to weld and re-cut the lug...a tedious undertaking, and not one for the inexperienced.
http://www.m1911.org/locking.htm
Cheers!
Tuner
Hi Jammer Six and guys,
No problem with asking, and I apologize for the delay in responding. My house has been a bit disrupted for the last few days with visitors, and my Vol 1 of Kuhnhausen is still among the missing. But the "thrust vector" mention is found in Vol 2, Page 42, Figure 29.
The writer (Kuhnhausen?) seems to be under the impression that the drag of the bullet in the barrel keeps the slide and barrel locked until the bullet exits and then somehow the unlocking occurs. I can't really follow the explanation because it is simply wrong. Figure 30, showing the slide and barrel fully locked after the bullet exits is also wrong, as are the comments explaining this.
What really happens is both simpler and more complex, but first, one has to accept the Law of Conservation of Momentum*, which says that any movement of a mass in one direction creates an equal movement in the opposite direction. This is just a better way of stating Newton's third law of motion, but the rule is simple: Mass times velocity in one direction equals mass times velocity in the other, or MV=MV. The bullet is low mass but high velocity, the barrel-slide unit is high mass but low velocity, so they balance. It is the bullet movement forward that causes recoil backward and shoves the barrel-slide unit back. If there were no frame, the two parts would never unlock and they would stay in motion until gravity and air resistance caused them to fall to the ground, still locked together.
But there is a frame, and a slide stop, and a link. So the link drags the barrel out of engagement with the slide, letting the slide continue on its own momentum to compress the recoil spring, cock the gun, and extract and eject the fired case. The energy stored in the recoil spring, combined with the "bounce" of the slide against the recoil spring guide (backed by the frame) then returns the slide to battery, chambering a fresh round on the way.
Side note: When a buffer is inserted, it absorbs some of the energy of the recoiling slide, but does not return any, so there is no "bounce"; the result can be failure of the slide to return to battery properly.
The pressure generated by the burning powder does not itself operate the gun. It moves the bullet and it is that movement and its opposite recoil that operates the pistol. If the barrel is blocked so the bullet cannot move, there is no recoil and the pistol will not operate.*
But the gas pressure alone will not open the action any more than gas pressure will open the action on, say, a Mauser rifle. The slide and barrel are locked just as firmly as the bolt on the Mauser and must be unlocked by an outside force, which is the link.
*Most folks have no trouble simply accepting the Law of Gravity and don't go jumping off buildings, yet I have been asked to "prove" the Law of Conservation of Momentum and have been flamed for not accepting Kuhnhausen's explanation. I respect Kuhnhausen, although we have never met, but I don't believe his books were written in fire on stone tablets and my own copies were delivered by USPS, not Moses.
**I have described doing this elsewhere and see no reason to repeat it, except to say that this kind of experiment must be carefully prepared and should be done only by those who fully understand the situation.
Jim
No problem with asking, and I apologize for the delay in responding. My house has been a bit disrupted for the last few days with visitors, and my Vol 1 of Kuhnhausen is still among the missing. But the "thrust vector" mention is found in Vol 2, Page 42, Figure 29.
The writer (Kuhnhausen?) seems to be under the impression that the drag of the bullet in the barrel keeps the slide and barrel locked until the bullet exits and then somehow the unlocking occurs. I can't really follow the explanation because it is simply wrong. Figure 30, showing the slide and barrel fully locked after the bullet exits is also wrong, as are the comments explaining this.
What really happens is both simpler and more complex, but first, one has to accept the Law of Conservation of Momentum*, which says that any movement of a mass in one direction creates an equal movement in the opposite direction. This is just a better way of stating Newton's third law of motion, but the rule is simple: Mass times velocity in one direction equals mass times velocity in the other, or MV=MV. The bullet is low mass but high velocity, the barrel-slide unit is high mass but low velocity, so they balance. It is the bullet movement forward that causes recoil backward and shoves the barrel-slide unit back. If there were no frame, the two parts would never unlock and they would stay in motion until gravity and air resistance caused them to fall to the ground, still locked together.
But there is a frame, and a slide stop, and a link. So the link drags the barrel out of engagement with the slide, letting the slide continue on its own momentum to compress the recoil spring, cock the gun, and extract and eject the fired case. The energy stored in the recoil spring, combined with the "bounce" of the slide against the recoil spring guide (backed by the frame) then returns the slide to battery, chambering a fresh round on the way.
Side note: When a buffer is inserted, it absorbs some of the energy of the recoiling slide, but does not return any, so there is no "bounce"; the result can be failure of the slide to return to battery properly.
The pressure generated by the burning powder does not itself operate the gun. It moves the bullet and it is that movement and its opposite recoil that operates the pistol. If the barrel is blocked so the bullet cannot move, there is no recoil and the pistol will not operate.*
But the gas pressure alone will not open the action any more than gas pressure will open the action on, say, a Mauser rifle. The slide and barrel are locked just as firmly as the bolt on the Mauser and must be unlocked by an outside force, which is the link.
*Most folks have no trouble simply accepting the Law of Gravity and don't go jumping off buildings, yet I have been asked to "prove" the Law of Conservation of Momentum and have been flamed for not accepting Kuhnhausen's explanation. I respect Kuhnhausen, although we have never met, but I don't believe his books were written in fire on stone tablets and my own copies were delivered by USPS, not Moses.
**I have described doing this elsewhere and see no reason to repeat it, except to say that this kind of experiment must be carefully prepared and should be done only by those who fully understand the situation.
Jim
Jammer Six
member
Jim, Tuner, Fuff, everyone, thanks.
I was in B.C. for the new year, and now I have to go study drawings and read Kuhnhausen.
Thanks again. I'm sure I'll come up with more questions. It's what I'm good at.
Happy New Year, everyone.
I was in B.C. for the new year, and now I have to go study drawings and read Kuhnhausen.
Thanks again. I'm sure I'll come up with more questions. It's what I'm good at.
Happy New Year, everyone.
romulus
Member
Given all the attention given to the link in this thread, especially the part about longer links exerting upward pressure, I got to thinking about the Dwyer Group Gripper that I installed in my dad's 1991 A1. Obviously the link is working to cam up the barrel deeper into the upper slide lugs...It also, I would guess, work opposite to Tuner's understanding that a hole should be slopped only at the top, but I can't see the GG working unless there is slop at the bottom of the link hole (lower hole) to allow the notched link to ride up and allow the barrel lugs to "reach" the slide.
I would then guess that the GG is mode of operation is based on a faulty principle that would necessarily end up, as noted, with possibly catastrophic results to the barrel...I'm seriously thinking of swapping out the GG (which my dad has barely shot) and re-fit the barrel at the feet (weld and recut.)
Also, can the group gripper, working under positively applied force, affect the aforementioned dwell time, or the spring force relatively insignificant compared to the force of the recoil? meaning, how timing sensitive are these guns really?
Thank you again
I would then guess that the GG is mode of operation is based on a faulty principle that would necessarily end up, as noted, with possibly catastrophic results to the barrel...I'm seriously thinking of swapping out the GG (which my dad has barely shot) and re-fit the barrel at the feet (weld and recut.)
Also, can the group gripper, working under positively applied force, affect the aforementioned dwell time, or the spring force relatively insignificant compared to the force of the recoil? meaning, how timing sensitive are these guns really?
Thank you again
1911Tuner
Moderator Emeritus
Group Gripper
Howdy romulus. I THINK I knw how the Dwyer thing works...I've never
used one or even seen one...but if I'm not mistaken, it works by forcing the
slidestop pin more firmly into the rear radius of the lower lug, using pressure from the recoil spring. Since the bottom of the lug isn't dead
horizontal, but at a slight angle, this would force the barrel upward into
a tighter vertical lockup.
Jim Keenan or Old Fuff may be able to give you the straight of the Dwyer's operation...or to correct me if I'm wrong.
Guys?
Standin' by...
Tuner
Howdy romulus. I THINK I knw how the Dwyer thing works...I've never
used one or even seen one...but if I'm not mistaken, it works by forcing the
slidestop pin more firmly into the rear radius of the lower lug, using pressure from the recoil spring. Since the bottom of the lug isn't dead
horizontal, but at a slight angle, this would force the barrel upward into
a tighter vertical lockup.
Jim Keenan or Old Fuff may be able to give you the straight of the Dwyer's operation...or to correct me if I'm wrong.
Guys?
Standin' by...
Tuner
Ah yes, Mr. Dwyer’s little “Group Gripper,†during my misspent youth I knew it well. It has a modified recoil spring guide with a very stiff flat spring inside. At the back end the spring has a sharp bend that faces upward and fits into a notch cut into the bottom of the link. The idea is that the spring pushes on the link and so moves it (and the barrel) upward when the pistol is in battery. In practice this won’t happen unless the link’s lower hole is elongated. What it does do to some degree is support the link, and therefore the barrel, which may, or may not affect the pistols accuracy.
I have put them in some pistols and thereafter accuracy improved – at least to a small degree, while in others there was no improvement whatsoever. It is one of the many gadgets on the market that sometimes help, but not often. So far as I can see that don’t hurt anything, and the inventor has made a lot of money off of it. The only time I would recommend using one is where, for whatever reason, the pistol itself cannot be modified in any way that prevents it being returned to its original condition. If accuracy is you’re goal, properly fitting a match grade barrel is a much better idea. If maximum reliability in uncertain (but probably harsh) environments is what you want leaving the pistol in a “service/stock†condition may be a better idea.
Tuner, you have no idea what you’ve missed …….
I have put them in some pistols and thereafter accuracy improved – at least to a small degree, while in others there was no improvement whatsoever. It is one of the many gadgets on the market that sometimes help, but not often. So far as I can see that don’t hurt anything, and the inventor has made a lot of money off of it. The only time I would recommend using one is where, for whatever reason, the pistol itself cannot be modified in any way that prevents it being returned to its original condition. If accuracy is you’re goal, properly fitting a match grade barrel is a much better idea. If maximum reliability in uncertain (but probably harsh) environments is what you want leaving the pistol in a “service/stock†condition may be a better idea.
Tuner, you have no idea what you’ve missed …….
1911Tuner
Moderator Emeritus
Missed it
Old Fuff said:
Tuner, you have no idea what you’ve missed
Yeah...I thought that thing looked like a gimmick, and thus avoided havin' a
go at it. Now, there's a few other things that I can't say that about...the
few that slipped in under my radar.
Old Fuff said:
Tuner, you have no idea what you’ve missed
Yeah...I thought that thing looked like a gimmick, and thus avoided havin' a
go at it. Now, there's a few other things that I can't say that about...the
few that slipped in under my radar.
yoky
Member
Norinco - problem with repeated broken barrel link
My friend has a serious problem. After 1500 round through His Norinco he changed recoil spring. Next shooting barrel link was broken in part around slide stop. He has changed link and situation was the some. We have measured if the slide stop is sitting OK in link and in the barrel lugs we haven’t seen any problem. Has anybody what is wrong? Only what we have seen is shorter gap between barrel and feed ramp normally is about 0.8 mm and measured is about, 0.5 mm. We did not find out any problem. My friend is in conviction that it was caused by stronger recoil spring. Can you help us?
Thank you in advance for updating me
yoky
My friend has a serious problem. After 1500 round through His Norinco he changed recoil spring. Next shooting barrel link was broken in part around slide stop. He has changed link and situation was the some. We have measured if the slide stop is sitting OK in link and in the barrel lugs we haven’t seen any problem. Has anybody what is wrong? Only what we have seen is shorter gap between barrel and feed ramp normally is about 0.8 mm and measured is about, 0.5 mm. We did not find out any problem. My friend is in conviction that it was caused by stronger recoil spring. Can you help us?
Thank you in advance for updating me
yoky
Dave Sample
member
Here is another way to do it. This is a Star 38 Super barrel that does not need a link. I do not use long links or short links. I leave these for the very clever guys to install. I always fit a barrel up to a .0278 or Number Three link. The link fit is very important , in my opinion, and I have seen terrible things done to them in the past. I have seen link pins turned into crankshafts by incompetent people. Note the barrel is marked 38 since I re-chambered it from a 9mm. It will shoot either, but pretty much destroys the 9mm cases. Also note the Armorers Mark up front. This way we know who did what.
Ah ... Dave.
The 9mm Luger cartridge has a tapered case that's .392" at the base, and .380" at the front.
The Colt .38 ACP/Super has a straight case that measurers .383" at the base and .382" at the front.
The Spanish were well known for some rather interesting chambers, but the one you made must be even more so ...
The 9mm Luger cartridge has a tapered case that's .392" at the base, and .380" at the front.
The Colt .38 ACP/Super has a straight case that measurers .383" at the base and .382" at the front.
The Spanish were well known for some rather interesting chambers, but the one you made must be even more so ...
1911Tuner
Moderator Emeritus
Broken Link
Howdy Yoky,
When a link breaks, it's most often caused by either the impact surface in the frame being set too far rearward or the barrel lug sitting too far forward...or both... and the barrel's rearward movement as it unlocks is being stopped by the link instead of the frame. It indicates a bad frame or barrel...or both.
Replacement is usually the simplest and cheapest way to go. Unusual for a Norinco to be that far out of spec, so it was probably a stack-up of tolerances between that particular frame and that particular barrel.
It's also possible that a short link is a player...but that little bug usually gives warning that something is wrong. Turn the pistol upside down and hand-cycle it. If the slide stops short or feels like it hits a snag, you've got a short link...or at least too short for that particular gun, given the tolerance stacking that seems to be there.
It gets worse...
If the link gives way before unlocking is complete...and it usually does... the lugs are usually damaged by the one crash, and probably will shear off or crack soon after, even if the problem that broke the link is corrected. The slide lugs could also suffer some damage.
Check for damage to the locking lugs at the front. If they are rounded off or they have a burr along the top edge at the front...known as flanging..
the slide has whacked the lugs. If the lugs on the barrel or ion the slide have a "stepped" appearance...same thing.
Look at the lower lug at the backside. If there's a dent about halfway between the junction with the barrel and the bottom of the feet, it was hit pretty hard when the barrel got caught between the frame and slide with the locking lugs still engaged.
Hard to tell if the damage was light or heavy without seeing the gun...and also hard to determine if a longer link can be used to keep it from happening again.
Wish I could tell ya more...
Howdy Yoky,
When a link breaks, it's most often caused by either the impact surface in the frame being set too far rearward or the barrel lug sitting too far forward...or both... and the barrel's rearward movement as it unlocks is being stopped by the link instead of the frame. It indicates a bad frame or barrel...or both.
Replacement is usually the simplest and cheapest way to go. Unusual for a Norinco to be that far out of spec, so it was probably a stack-up of tolerances between that particular frame and that particular barrel.
It's also possible that a short link is a player...but that little bug usually gives warning that something is wrong. Turn the pistol upside down and hand-cycle it. If the slide stops short or feels like it hits a snag, you've got a short link...or at least too short for that particular gun, given the tolerance stacking that seems to be there.
It gets worse...
If the link gives way before unlocking is complete...and it usually does... the lugs are usually damaged by the one crash, and probably will shear off or crack soon after, even if the problem that broke the link is corrected. The slide lugs could also suffer some damage.
Check for damage to the locking lugs at the front. If they are rounded off or they have a burr along the top edge at the front...known as flanging..
the slide has whacked the lugs. If the lugs on the barrel or ion the slide have a "stepped" appearance...same thing.
Look at the lower lug at the backside. If there's a dent about halfway between the junction with the barrel and the bottom of the feet, it was hit pretty hard when the barrel got caught between the frame and slide with the locking lugs still engaged.
Hard to tell if the damage was light or heavy without seeing the gun...and also hard to determine if a longer link can be used to keep it from happening again.
Wish I could tell ya more...
yoky
Member
broken link
Tuner
Thank you very much you give to me another idea what can be wrong. We will inspect the gun closely as much as possible. I have to try to post some pictures. I understand it would be difficult to say exactly what is wrong without having the gun in hands and without see it in nature for analyses.
Together with pictures I try to find out more details about the gun.. This is not first time you have helped me
Thank you very much, and your help is highly appreciated. Now thinking about the problem I guess you are right really something is out of spec. I will inspect another Norinco for comparison, barrel frame etc.
Best regards
Yoky
Tuner
Thank you very much you give to me another idea what can be wrong. We will inspect the gun closely as much as possible. I have to try to post some pictures. I understand it would be difficult to say exactly what is wrong without having the gun in hands and without see it in nature for analyses.
Together with pictures I try to find out more details about the gun.. This is not first time you have helped me
Thank you very much, and your help is highly appreciated. Now thinking about the problem I guess you are right really something is out of spec. I will inspect another Norinco for comparison, barrel frame etc.
Best regards
Yoky
Dave Sample
member
Ah, Old Fuff. You did not pay any attention to what I said about this Star Super Modelo B. This chamber started out in life as a 9mm. I re-chambered it to 38 super with a Nonte' Reamer so that it now headspaces like a 45 ACP and therefore, the mouth of the chamber will take a 9mm and the extractor (external) will hold it against the breechface while it lights up. I know this is not the ususal way to go, but since you know everything, you should know that these Stars were meant to take either a 9mm barrel or a 38 Largo barrel with matching recoil springs and they use the same magazine. The basic gun is the same for both calibers. In 38 Largo, it's a Star AS and in 9mm, it's a B. I know you don't read much of what I say, and I never read your long winded disertations, so this is not for your benefit, but rather , for the others on this forum that wish to improve their knowlege of this Spanish Steel. I have done at least a dozen of these barrel and spring conversions , so I know it works.
This is what it feeds like greased green goat grunty now.
No Stem Bind here. Note the loaded chamber indicator at the upper rear of the port. Nice feature.
This is what it feeds like greased green goat grunty now.
No Stem Bind here. Note the loaded chamber indicator at the upper rear of the port. Nice feature.
- Status
