"Other than gas operation"


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Trent
November 24, 2011, 10:32 PM
Was cleaning the gun room this week and found my old paintball gear from eras gone by. Gave it to my oldest son.

But it triggered an old thought I had awhile back with a method about (possibly) how to make semi-auto firearms more accurate.

My idea was to eliminate the barrel port on an AR-15, rework the gas "plumbing" on the gas operation system to accept a feed from a high pressure N2 paintball tank (with appropriate valving), then wire an electronic microswitch to be activated on the RETURN of the trigger.

So you pull the trigger, the gun goes boom, no gas is bled off to cycle the weapon which can make your shot placement inconsistent. You release the trigger and during the release process the N2 valve fires, cycling the weapon.

No grit in the gun (it won't crap where it eats, anymore), no accuracy degradation, and you could even gain the ability to add a push button "cycle my weapon" feature (since you could cycle on demand instead of only when fired).

Is this idea too far out there? Or does it sound like something that may work, and have some benefits?

Might help our British brethren who can't own gas-operated semi-automatic firearms - it would give them the ability to actually cycle their weapons (via N2) without having to yank the charging handle each shot.

Essentially it (should) have the accuracy of a bolt gun with the features of a semi-auto.

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M-Cameron
November 24, 2011, 10:38 PM
that sounds overly complicated and prone to failure.

it adds in unnecessary electrical and pneumatic components....

then theres also the issue of having to change the air tanks....or else the gun wont cycle.....not something ide want to happen in the field....or possibly in a situation where my life depended on it.



kudos to thinking outside the box.......but sometimes things arent invented for a reason.

Deus Machina
November 24, 2011, 11:11 PM
It would probably work perfectly fine. The Autococker (so called because they started as pump-actions, and had pneumatics rigged up to recock themselves semi-automatically) work on the same principle, and they're perfectly reliable as long as you set them up right and don't fiddle with it. In fact, you could literally just make an adapter to a gas-piston bolt and screw the pieces right to the gun. You might just need to switch out the piston, which has a 1"-stroke, to a longer one.

Not something I would use as a service or self-defense weapon, but would be fine for the range.

Two things, though. IIRC, the ATF has something against electronic controls, or at least ones separated from the mechanical trigger mechanism itself.

Two, the actual motion of an AR recocking doesn't really do much until the bullet has actually left the barrel. The gas system pressurizes shortly before the bullet is gone, then has to wait until the pressure in the barrel and casing has dropped enough to let the bolt turn and extract the brass. So it's mostly a fix for a nonexistent problem, even if it might make things more consistent in the same manner changing to a bolt-action would.

230RN
November 24, 2011, 11:23 PM
So you pull the trigger, the gun goes boom, no gas is bled off to cycle the weapon which can make your shot placement inconsistent. You release the trigger and during the release process the N2 valve fires, cycling the weapon.

FYI, relevant to your remark, my Yugo SKS with the grenade-launcher gas cutoff valve seems to shoot slightly more accurately with the gas valve shut than when the gas blows all those parts around. Can't prove it, since I haven't really shot it that much, but it seems that way.

I don't know how general that might be with respect to other gas-operated semiautos, but that's the way it looks so far.

As far as having a separate pressure system for cycling is concerned, besides adding unnecessary complexity (in terms of battlefield conditions), the reduced pressure with each shot may add another unintended variable that would reduce accuracy in terms of inconsistent feeding.

I don't believe modern combat requires superior accuracy as much as volume of fire, so it strikes me if your goal is accuracy for the sake of accuracy (as opposed to combat efficiency), go to a hand-operated bolt gun tuned for that goal. Like snipers use.

Just my opinion.

gennro
November 24, 2011, 11:27 PM
It would still be a gas operated semi-automatic weapon though. Sounds like a fix for a non-exsistant problem.

Rangersnipersf
November 25, 2011, 01:23 AM
deus, I like the idea, As an army ranger sniper And in SF for the last 11 years, not to insult your intelligence because your idea is unique. but first understand how a gas operated assault weapon works. there is no gas feed, it works off of a roller rocker purge system. ("Special forces snipers, and rangers know what im talking about") I carry an m-4 which it has a gas operation reload system the features on this weapon are 3 round burst, and semi auto, any expert marksman will tell you that semi is all that's needed, unless you are doing what us rangers like to call 60 into 500, which makes the enemy think that there is a company of soldiers, not a platoon. u use the burst in this situation, other than that, the 3 round burst feature, reduces accuracy, by 88% due to rise and re-adjustment of your cheek to stock weld. Now back to the topic. the reason a weapon with this feature is mainly based upon the excess gas that is created by the powder in the shell. so when you shoot semi (best way) what takes place is you shoot, then as the round just passes the gas feed some of the force which is powering the projectile flows into the gas tub sending the force back to re-chamber another round. your weapon gets dirty cause of the UN-used powder. which leaves the residue on your weapon, from my professional opinion in using these weapons in combat for the last 10 years, hooking up an alternate feed to reload is setting yourself up for failure. alternating these weapons action mechanisms will essentially cause harm to the weapon, because they are designed that way by experts, not just one guy, if they thought an o2 tank would be more proficient instead of the weapons design, they would have done it. What i started doing during my 1st combat tour was instead of using gun oil, use A.t.F....lol Yes automatic transmission fluid. it cleans all of the internal actions while keeping you weapon cool. trust a combat condition sf soldier, i spent years over there. instead of cleaning and oiling your weapon after every use, with ATF youll clean it after every 1,000 rounds, just try it, you will love it, but in reference to your idea, i think its cool, but altering a weapons stock firing and reloading mechanisms, you seting yourself up for a whole bunch of trouble. try my way. also i believe i read that you are using an AR-15. That's a .223 which is the same round as a 5.56. all they are is a .22 on steroids, but they are dirty guns, try getting into reloading, or spending more money on cleaner ammo, when it comes to recoil u shouldnt be having in issue with that, those weapons are made to be used in combat, the recoil spring is abot 17" long, and are designed to be used alot, shot placement it the key, if your getting too much rise, you might want to participate in my tactical and precision firearms training. it is ran by all special opps soldiers and infantry men with years of combat experience. if you interested its in Pa. for rates and more information contact me @ 412-616-3160. rise issues are most of the time corrected by using a lighter grain, but a ,223 you should have no issues, u could also send you weapon to me, ill test and tune it. then return it to u.

Rangersnipersf
November 25, 2011, 01:56 AM
It would probably work perfectly fine. The Autococker (so called because they started as pump-actions, and had pneumatics rigged up to recock themselves semi-automatically) work on the same principle, and they're perfectly reliable as long as you set them up right and don't fiddle with it. In fact, you could literally just make an adapter to a gas-piston bolt and screw the pieces right to the gun. You might just need to switch out the piston, which has a 1"-stroke, to a longer one.

Not something I would use as a service or self-defense weapon, but would be fine for the range.

Two things, though. IIRC, the ATF has something against electronic controls, or at least ones separated from the mechanical trigger mechanism itself.

Two, the actual motion of an AR recocking doesn't really do much until the bullet has actually left the barrel. The gas system pressurizes shortly before the bullet is gone, then has to wait until the pressure in the barrel and casing has dropped enough to let the bolt turn and extract the brass. So it's mostly a fix for a nonexistent problem, even if it might make things more consistent in the same manner changing to a bolt-action would.
to correct a persons post on yours, RE: ATF LAW. he was not talking a mechanically operated trigger, to totally bust u on this, a everything on a semi or automatic weapon is mechanical. the ATF has laws against remote or electronically opperated firing mechanisms. and on another topic, a gas opperated weapon does not have a gas chamber or reservoir. thats y u have to rack the initial round,unless you are doing a combat reload! a gas operated roller rocker assault weapons chamber is filled just before the projectile passes the intake end of the line, therefor it sends the gas back to the bolt and the bolt actually rolls completely into the the butt stock and the recoil spring sends the bolt forward acquiring another round, it doesn't roll back just an inch, a 223 (ar-15) round is bigger than an inch. the bolt precisely goes into the bolt and recoil spring chsmber 5.91 inches from the firing position, trust me im a master gun smith and i build custom ar's and m-4 for swat teams, police depts and civilians, I've built over 12,000 weapons in my life. but like i said to alter the weapons firing/reloading features is not something you should do!!!!!!!!!!!!!!!!!!!!!!!!!!!! period ur asking for a massive weapon failure, obstructions, the gun could even blow up in you face, but what the ATF does have serious laws against alterations to firing and reloading mech alterations

TenMillimaster
November 25, 2011, 02:04 AM
My idea was to eliminate the barrel port on an AR-15, rework the gas "plumbing" on the gas operation system to accept a feed from a high pressure N2 paintball tank (with appropriate valving), then wire an electronic microswitch to be activated on the RETURN of the trigger.


There is an entire class of firearms operation that eliminates that gas port and make true free floating possible. Blowback! Can it handle rifle pressures? Sure, with some figuring. the G3 is roller delayed blowback and it does just fine, I hear. Even is the basis for one of the worlds best(and expensive) autoloading sniper rifles.

Much, much simpler than what you're suggesting.

Jim Watson
November 25, 2011, 02:27 AM
I have a rebarrelled and otherwise massaged AR15 that is somewhat more accurate than my best bolt action. You may NOT install an external actuator on it or otherwise mess with success. Its only flaw is throwing my prepped target brass in the weeds. I should have had it converted to manual operation while I was setting it up. But I don't think that would have helped its accuracy, it is running way sub MOA, probably at my holding limit.

I don't think such gimmickry would let a Brit assemble a rifle that would function just like an automatic. Their bureaucrats have even more power than ours, and they would not allow that.

Sure, you can build an autoloading action that does not use separate gas handling, of which the H&K/Vorgrimmer action is the leading deployed example. But they don't seem particularly accurate until you get up to the 18 lb PSG-1.

I wonder how accurate Mr Garand's primer setback action would have been if given equal development.

I do wish the Special Forces would explain what a roller rocker gas purge system is, the term is not in my ordinary manuals.

Trent
November 25, 2011, 02:53 AM
There is an entire class of firearms operation that eliminates that gas port and make true free floating possible. Blowback! Can it handle rifle pressures? Sure, with some figuring. the G3 is roller delayed blowback and it does just fine, I hear. Even is the basis for one of the worlds best(and expensive) autoloading sniper rifles.

Much, much simpler than what you're suggesting.


I own a G3 and a CETME, I'm familiar with the action. Believe me I've scrubbed out my share of crap out of chamber flutes. Once used engine oil to lube the dang thing when I forgot my toolkit at home with the oil in it. Works in a pinch. :)

The issue is that ANY gas-reaction system (gas operated or blowback) allows SOME gas to operate your weapon. SOME gas, but not ever always the SAME amount. It's easy to prove this - if it somehow magically DID use the exact same force diversion off of each shot, your shell casings would all travel the exact same distance and land in a nice, neat pile on top of one another! (or, less subjectively, I'd be able to get as consistent velocity readings out of it as I do my bolt guns)

The gas diverted happens PRIOR to the bullet leaving the muzzle. Sure, the action shouldn't move until pressures drop and the bullet is out of the muzzle. That shouldn't affect your shot any more than the initial recoil impulse already does. But the amount (volume) of gas varies, as does the pressure, leading to a higher standard deviation of velocity when compared to a bolt action rifle, which divides no amount of gas.

By triggering the cycling from a secondary source after the bullet is out, you retain fast loading but take out ALL sources which could be detrimental to the shot's accuracy - except the barrel quality, the ammo quality, and the shooter quality.

I have a rebarrelled and otherwise massaged AR15 that is somewhat more accurate than my best bolt action. You may NOT install an external actuator on it or otherwise mess with success. Its only flaw is throwing my prepped target brass in the weeds. I should have had it converted to manual operation while I was setting it up. But I don't think that would have helped its accuracy, it is running way sub MOA, probably at my holding limit.

I don't think such gimmickry would let a Brit assemble a rifle that would function just like an automatic. Their bureaucrats have even more power than ours, and they would not allow that.

Sure, you can build an autoloading action that does not use separate gas handling, of which the H&K/Vorgrimmer action is the leading deployed example. But they don't seem particularly accurate until you get up to the 18 lb PSG-1.

I wonder how accurate Mr Garand's primer setback action would have been if given equal development.

I do wish the Special Forces would explain what a roller rocker gas purge system is, the term is not in my ordinary manuals.

Jim, I know you have been around a long time, and you have my respect - very few people could put together an AR rifle that accurate. My best effort fell far short of my expectations; was an expensive experiment with an air gauged custom reamed 223 Wylde chamber and 80 grain bullets that didn't pan out so well. May have just go a lemon of a barrel, but I couldn't get highly consistent velocities out of it. Groups at 100 yards are respectable, but the further out it goes, the thing strings out. Never got my velocity problem pinned down - which is why I started thinking about alternative ways to cycle the action which weren't so dirty, or so inconsistent.

My question to you would be, on AR-15's with manual actions (like the afforementioned Brits use in competitions), are they "as accurate", or "more accurate" than gas cycled actions?

Doing a retrofit of an action to cycle outside of the firing process would be (yet another) expensive experiment, but recently I read that the brits use manually operated AR15's. It would seem the answer would be right there, but I can't find any conclusive information one way or the other.

(I remember reading long ago about your house fire, by the way, glad you got out of that in one piece!)

jerkface11
November 25, 2011, 10:16 AM
but first understand how a gas operated assault weapon works. there is no gas feed, it works off of a roller rocker purge system.

Roller rockers????

Trent
November 25, 2011, 12:08 PM
Yeah... I couldn't think of a polite way to respond to that either, jerkface11, so I opted to just skip it.

Vern Humphrey
November 25, 2011, 01:37 PM
no gas is bled off to cycle the weapon which can make your shot placement inconsistent
Given the accuracy achievable with tuned gas-operated rifles (for example M15-style varmit rifles), what is the basis for this claim?

Justin
November 25, 2011, 01:41 PM
Sean, I mean, er, Rangersnipersf, it sure sounds like you've got a lot of real-world experience! Would you mind posting some of the photos from your classes?

Also, since you're a full-time Special Forces warrior, would you mind telling us how you're able to find the time to a work as a roofer, (http://pittsburgh.craigslist.org/hss/2660724333.html) bike ride organizer, (http://www.bikenightusa.com/event/pa/pittsburgh/bike_night_at_the_shark/9975) build 15 custom Mustangs, (http://www.allfordmustangs.com/forums/2756951-post13.html)and find the time to work as a ghost hunter, too? (http://realhaunts.wetpaint.com/)

I mean, that's pretty hardcore. I barely have the time to do even 1/10 of that stuff, and I don't have to deal with the rigors of a demanding schedule of clandestine military deployments.

rcmodel
November 25, 2011, 01:48 PM
trust me im a master gun smith
Now, thats funny right there!

I mean, that's pretty hardcore.
That's even funnier!!!!
I don't care who ya are!!

rc

Carl N. Brown
November 25, 2011, 02:01 PM
Since the timing of the AR action is such that the bolt is not unlocked until after the bullet has left the barrel, I don't see movement of the bolt carrier and bolt as affecting accuracy that much.

However, proper gas operation is dependent on a specific level of gas pressure. This usually limits you to a specific range of power in the cartridge. An extrenal source of gas pressure would give you the same operating pressure regardless of whether the cartridges were loaded for subsonic, or small game foraging, or full tilt boogie power levels.

Tim the student
November 25, 2011, 02:09 PM
Trent, I don't see what the real benefit is I guess, given that my AR shoots as well or better than all my bolt guns. Even if it could work flawlessly, I just don't see what the real benefit is.

Sean, I mean, er, Rangersnipersf, it sure sounds like you've got a lot of real-world experience! Would you mind posting some of the photos from your classes?

Also, since you're a full-time Special Forces warrior, would you mind telling us how you're able to find the time to a work as a roofer, bike ride organizer, build 15 custom Mustangs, and find the time to work as a ghost hunter, too?

I mean, that's pretty hardcore. I barely have the time to do even 1/10 of that stuff, and I don't have to deal with the rigors of a demanding schedule of clandestine military deployments.

Thank god I wasn't the only one that found that stuff and wanted to call him out on it. Don't forget that he also built over 12,000 weapons in his life. Busy indeed.

Pretty interesting that there is a post here (http://www.topix.com/forum/county/allegheny-pa/TGD9H0S6C88K0BDAG) from "Sean Hein" in which the poster refers to himself as a ranger and a "spec opps" soldier. Strange, huh?

But hey, I'm sure I could get excellent training from this Craigslist ad. (http://pittsburgh.craigslist.org/lss/2719337252.html)

BullfrogKen
November 25, 2011, 02:30 PM
trust me im a master gun smith and i build custom ar's and m-4 for swat teams, police depts and civilians, I've built over 12,000 weapons in my life.

Really? Do you work for Colt or Bushmaster? That's pretty high volume. If you're building these on your own then we need to see your Manufacturer's FFL license if you want to market those services here.

redneckdan
November 25, 2011, 02:35 PM
Jim, I know you have been around a long time, and you have my respect - very few people could put together an AR rifle that accurate.

You are joking right? It is easier to get an AR to shoot than it is a bolt gun. Float a good barrel....that is it. No action truing, no bedding receivers, no nothing. Install a quality barrel with a cheap DPMS aluminum forend, check the receiver fit and bolt/carrier travel to ensure nothing binds and you are done. If your boom stick won't shoot a 69gr SMK over 25.0gr of 748 into itty bitty groups on the short course then you have a gun problem.

Walkalong
November 25, 2011, 02:48 PM
heres the best response i think ull get, i am a ranger so im very stright forwardRangers are well educated, and can all write well above a 4th grade level. It is very hard to take you seriously when you write at a 3rd or 4th grade level. Just sayin'.

hso
November 25, 2011, 03:01 PM
I'm confused, not uncommon, but I thought Ft. Benning was near Columbus GA and not in PA. I also don't understand how you could build 12,000 weapons with a 12 year career in the military as a Ranger/Sniper/SF. What further confuses me is how you would use the term "roller rocker purge system" for the operating system for an AR when the schematic for the AR's mechanism shows nothing that could be called that and no components rocking or rolling. There are even some good animated video showing the rotating bolt operation of the AR with the direct impingement system driving the bolt carrier that further denies the use of anything like the term you've made up, amongst other things. http://www.youtube.com/watch?v=RKGlthExwRQ&feature=related

Robert
November 25, 2011, 03:11 PM
heres the best response i think ull get, i am a ranger so im very stright forward

I stopped reading right there... well not really but I wished I had.

As others have said, if you are going to make the claims you are making please provide certs or documentation that will backup your claim. It is nothing personal but anyone can claim to be anything on the internet. I am the King of Prussia by the way.

FIVETWOSEVEN
November 25, 2011, 03:25 PM
I am the King of Prussia by the way.

Seems legit.......other than the fact that I'M the King of Prussia!:mad:

BullfrogKen
November 25, 2011, 03:34 PM
I've shopped at the King of Prussia (http://en.wikipedia.org/wiki/King_of_Prussia_Mall)mall, and I didn't see either of you there.

hso
November 25, 2011, 03:41 PM
Ken,

Why don't you invite Rangersnipersf to your club so he can show is training techniques to the other pros there?

FIVETWOSEVEN
November 25, 2011, 03:43 PM
I was on vacation Ken, gosh, I'm a human too! Or maybe thats just a cover story and I'm really just one of those people concealing a G36 and a MK23 and duct taping armor plates to myself...

BullfrogKen
November 25, 2011, 03:49 PM
Ken,

Why don't you invite Rangersnipersf to your club so he can show is training techniques to the other pros there?

I could.


Or I could go out to his compound.

http://pittsburgh.craigslist.org/lss/2719337252.html

state of the art tactical training, for law enforcement, military, private security and civilians who want to learn how to be come military sniper grade accurate, 8 phases offered, from hand to hand, pressure point control tactics, precision target acquisition out to 1000 yrds, if you need a tactical defense item custom built buy a master smith or your your current tuned to perfection, contact SSgt Hein. U.S. Army Ranger Sniper/ Special Forces, with years of close quarters and long range combat experience. CALL ME @ 412-616-3160, we handle classes of 12 at a time. Mom, or lady, need some self defense training at a rate that is hard to beat, or if you are interested in tactical training, let me know. we have a staff of 6 US Special OPPS Soldiers! or you can e-mail me @ heinsean@yahoo.com!!!!!!!! classes run year round! new barracks are being installed now! so out of state agencies,or civilians are welcomed. HUNTERS WANT TO REALLY BE ABLE TO HIT THAT DEER 1 AND DONE! DONT DELAY CALL TODAY!!!!!!!!!!!!!!!!!!!!! we will have you honed in for deer season

I'm a little old to be playing around with hand to hand combat and pressure point controls. My goal with long range shooting was not to get that close, anyway.

But I could make a trip out to see the facilities. I know of three 1,000 yard ranges in Pennsylvania. None of them are out in the Pittsburg area, though. Nice to see if there's one more.

hso
November 25, 2011, 05:30 PM
Cool, you and Sam could pay him a visit and see what his school looks like.

bikerdoc
November 25, 2011, 06:09 PM
Rangers dont brag.

Chindo18Z
November 25, 2011, 07:28 PM
Rangersnipersf:

Employment of proper grammar, punctuation, & paragraph format are conducive to being taken seriously when you write.

...gas operated roller rocker assault weapons chamber...
It's painful to even think about responding. I'll pass on the above quote and let someone else chew on the bone.

Regarding your claimed credentials...

After eleven years in SF, you don't seem to have kept pace with your peers. Most SF NCOs at 14 years of service are senior SFCs with their packets in front of the next E-8 board. Many of them are already Master Sergeants. All of them know how to properly write the rank abbreviation for an Army E-6. Yes, I read your Craigslist ad. :rolleyes:

You are evidently the sole SF or Ranger user of the M4 Carbine to be found in either Regiment. A real Army of One. :rolleyes:

I'm unaware of any tabbed individual in any Group or Batt who has had the time to put together 12,000 lifetime weapons...while deploying over the last 10 years and of the age to be an eleven year, E-6 SF veteran. I'm pretty familiar with who the serious gun-bunnies are in the community. You've surpassed the lifetime production and maintenance rate for any of our L3 contracted SF gunsmiths. Perhaps you should apply for their job? I guess you must have had a busy gunsmithing life during your teen years? :rolleyes:

Since you live in PA, perhaps you commute to Bragg? Or is it Benning? Or is it HAAF? Or perhaps you are part of 20th or 19th? I know a lot of their folks...maybe we have mutual friends. :rolleyes:

Ranger? SF? Do tell. To which Batt or Group are you assigned? For instance, I was a Ranger at 2/75, but now I'm just an E-9 assigned to 10th SFG(A). After 35 years of service in Army SOF, I happen to know a lot of people. In fact, I probably know your CSM (Guard or Active, Ranger or SF). Let's compare notes...

I don't normally flame folks who post on The High Road, but you've invited this by besmirching the good name of my unit and my friends. Friends who have in some cases died or been severely wounded so that you can continue to indulge your 1st Amendment rights. Not very High Road of you. This is a room full of adults...you might want to remember that.

If you're not getting what I'm saying, I'll be blunt:

YOU ARE NOT ARMY SPECIAL FORCES
YOU ARE NOT AN ARMY RANGER

You are an embarrassment to this board and the good name of the folks who actually work in the profession you claim.

P.S. - If by some chance, you actually are still serving in the Army...clean up your profile. It's jacked up. I shouldn't have to explain why.

Tim the student
November 25, 2011, 07:58 PM
^^ LOL that the 18Z found this thread, and this guy.

Chindo18Z
November 25, 2011, 08:41 PM
Trent: If I'm understanding your concept...the weapon would fire from a locked bolt, which would not recoil upon firing a cartridge? Am I tracking correctly?

Sounds interesting.

Cosmoline
November 26, 2011, 01:46 PM
Re. the OP--wouldn't it be a heck of a lot easier to just shut off the gas system and operate your AR as a straight pull. I believe this is actually done in some nations which disallow semis entirely. I'm not sure about the mechanical issues involved but I believe they're not terribly complicated. Just make an upper with a barrel that hasn't had the gas port drilled yet. Am I missing anything here?

Trent
November 26, 2011, 02:44 PM
Chindo - your first post made me laugh. Hard. Thank you, both for serving and for handling that in such a professional manner. :)

Second post, the weapon would fire from a locked bolt, but there WOULD still be a recoil impulse from the fired round moving AND from gas exiting the barrel, pushing back. (Every action has an equal and opposite reaction). The weapon's action would not cycle until the N2 release was triggered.

Everyone seems to have focused on the accuracy side of things. But increased accuracy is only part of the solution. At short range - as one previous poster mentioned - AR15's (and bigger brethren, AR10's) would group very well. It takes a 1,000 feet per second difference (from 3,000 fps to 2,000 fps) in velocity to make a 5" vertical deviation in your shot trajectory at 100 yards. Obviously, we're not talking about THAT large of a gap with the inconsistency of a gas operated weapon.

Now, factor in an M855 with a ballistic coefficient of .304. It takes a 100 fps difference in muzzle velocity to change the trajectory 5" at 500 yards. Or, taken another way, at +/- 50 fps it is enough to throw a shot out of a "kill zone". 100 FPS won't make a hill of beans difference at 100 yards but at 500, the slower moving projectiles will not only be affected by gravity longer before striking, but wind will have longer to work on them, and bullet twist (spin drift) will interact with wind that much more. (Solving wind problems with spin drift accounted for are rather complex to do ... without the added uncertainties caused by inconsistency in time of flight)

Factory ammo, on it's own, is enough to account for a substantial part of a velocity deviation sufficient for that amount of deviation - maybe 20-30% (depends on chamber, barrel, fitting of the gas tube in the gas block, etc). By the time the gas operation comes in to effect, you've amplified whatever deviation the ammunition already had that much further.

Meanwhile, while the gas operates to serve the bolt, it deposits a healthy amount of fouling, directly in the action of the weapon. This is a secondary consideration that is largely solved by modern alternatives - in FN SCAR, F2000, P90, and other newer weapons, fouling is damn near nonexistant and short range accuracy is great.

Regarding cosmoline's post - yes, you could just get rid of the gas system entirely, but the whole point is to have fast follow up shots. By triggering (mechanically or electrically) the cycling of the weapon via N2 charge on the release of the trigger, there is rapid reloading of the weapon without manually pulling a bolt.

I was thinking the AR15/AR10 chassis would be a great proofing platform because it already has a nice place to hook up a charge line (the gas tube). Any other weapon would require substantial machining or re-engineering to fit this idea to.

The ultimate application would be a larger caliber action with an action purpose built specifically to accommodate this. In the minds eye, it would have a quick-exchangable N2 tank in the stock, with a mechanical (not electric) trigger-release activation. I'm fond of big cartridges - 300 Win Mag, 338 Lapua, etc, and semi-auto actions are rare and expensive in these calibers. With this system I wouldn't have to port or do any engineering to determine where / how large to put a gas port in a large bore, be concerned with regulating large volumes of gas pressures, etc, as the bore would be clean. :)

What I'd like to have in the end, is a purpose built long range rifle with auto loading capability and bolt-gun levels of accuracy.

The AR15 would be a great platform to test on, IMO, as initial fitting and testing would be substantially easier than a ground-up receiver / action design, making actual data easier to obtain.

(As far as blocking the gas system off on the AR, I was planning on machining a gas block with no port to press on to the barrel in lieu of the front sight/gas block. I have 11 barrels left, I could test with, of various lengths / types, but all are drilled. This would let me use what I have on hand without having a special barrel made.)

Robert
November 26, 2011, 02:50 PM
Trent,
I will admit that I really didn't understand a lot of this, but it looks very interesting and while it may not be adopted en mass in the real world I think it is a heck of an idea that would at least provide form some good tinkering and problem solving.

Trent
November 26, 2011, 03:22 PM
Gus, I don't understand a lot either.

The reason I posted this here on THR is becomes there's some very knowledgeable folks on this forum, and I wanted to find out if anything like this has been tried previously. (No reason to reinvent the wheel, so to speak).

Doesn't really matter if it's commercially viable, or applicable to any specific purpose. The big experiment would be if an automatic loading, highly accurate firearm can be manufactured without relying on the gas from the discharged cartridge as an actuator, and to find out if such a firearm would offer any cleanliness / accuracy / reliability benefits.

Making a perfectly clean shooting, highly accurate, and extremely reliable weapon, isn't that something akin to the holy grail of gunsmithing?

:)

Robert
November 26, 2011, 03:38 PM
Would it fire from a cartridge like a normal rifle or use the gass to propel a single projectile?

Devonai
November 26, 2011, 03:54 PM
You are an embarrassment to this board and the good name of the folks who actually work in the profession you claim.

Thank you for saying what needed to be said, Sergeant Major.

SRA Kantrowitz, 2T2X1, formerly SPC Kantrowitz, 11B1O, Weekend Warrior with zero rifle builds. :)

Trent
November 26, 2011, 03:55 PM
Gus,

It would fire a conventional cartridge (primer, smokeless powder, brass casing, projectile all remain unchanged).

But instead of using gas pressure from the fired cartridge to cycle the firearm, it would use an external source of high pressure nitrogen tank (regularly used in paintball) to cycle the firearm action (to extract, eject, and chamber the next round).

Thus no fouling from gas deposits (anywhere), no loss of precision from "some" of the gas being diverted, and more reliability (ability to cycle a cartridge that does not fire, etc).

As people have mentioned above the "accuracy" part is really splitting hairs as it wouldn't be noticeable until you're shooting at very long range, and modern firearms are far more accurate than those produced 15 or 30 years ago.

Trent
November 26, 2011, 03:59 PM
I should better qualify that previous post.

"SOME" modern firearms are far more accurate than "MOST" firearms that were produced...

I know someone will blast me over that generalization I made as 15 or 30 years ago there were some wonderfully accurate firearms in production, and there are many specimens of "pretty crappy" firearms being put together today.

You get my meaning though. Overall there's more accurate guns being produced now, than there used to be.

H&Hhunter
November 26, 2011, 05:04 PM
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Pressure point control? Really.. Do you guys teach Mr. Spock style mind melding too? Because that is something that I would be interested in!

Jim Watson
November 26, 2011, 06:17 PM
Velocity variation of 100fps due to gas operation?
I don't think so. I am not the best loader around, I see extreme spreads of 40 fps in my lesser attempts at making an AR a Long Range rifle and serious shooters do a lot better than that. Further, most reports of long range groups show more horizontal due to wind than vertical due to velocity variation.

But if you want to ride the hobby horse, it is time to start bending metal. You can only hash stuff out on the internet productively for so long.

Robert
November 26, 2011, 07:22 PM
Thus no fouling from gas deposits (anywhere),
The barrel would still have fouling from burning powder and copper. Not trying to be argumentative just trying to wrap my poor public school mind around it.

PercyShelley
November 30, 2011, 07:52 PM
RE: the OP


I have heard of pneumatically driven autoloaders for very large cannon (~75mm), but not for anything smaller than that. The idea seems sound enough, legal concerns aside. Dunno if it would be as compact or reliable as a conventional self-powered system, but it does at least sound workable.

Alternatively, what's the weight of the springs used in airsoft guns? An electrically-powered autoloading system seems plausible too.

I also vaguely recall some sort of revolver grenade launcher where the spin of the cylinder was assisted by some sort of wind-up spring. The striker maybe?

So yeah, externally-powered systems are common in the 25mm+ range. Not sure how well they scale down, but it would probably work.

robMaine
December 1, 2011, 10:06 PM
Sorry to continue being slightly off topic, but could this(http://www.westview.com/wwwv.html) Sean V. Hein, be the same as our "Ranger".

Chindo18Z
December 2, 2011, 12:33 PM
Yes. Same person.

http://pittsburgh.craigslist.org/lss/2719337252.html

http://www.post-gazette.com/pg/07087/773154-100.stm

http://www.topix.com/forum/county/allegheny-pa/TGD9H0S6C88K0BDAG

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