Gas Piston Variation

Something I debated over with a fellow AR nut. There's been comments made about the gas piston ARs not being as accurate. This due to barrel flex from the gas piston being mounted to the barrel. So when the piston operates it applies physical force to the top of the barrel. This applied leverage can cause barrel flex and possibly create a different point of impact as the barrel flexes back.

Here's an idea I had. Use a specially designed aluminum free float forearm, attach the piston assembly to the forearm, and use a gas tube to connect the gas block to the piston assembly. Would that potentially increase accuracy? Would that put too much stress on the forearm or barrel nut? Would the different materials be better? What would be the feasability?

Is this something that would work or already been tried and failed? Give me your input.

Scott

Why not just simply use the viron system? if it works... If I had unlimited funds (US govt comes to mind) I'd try that and your method, and see which one performs better.

Does anybody know if this is something that has been considered before? I was just curious if this would help accuracy or just create a whole new set of problems.

Scott

Your idea sounds a little complicated and with the gas tube mounted externally on the forearm it sounds more prone to damage. Im a firm believer in the KISS principle(Keep It Simple Stupid)

In current form, the AR system is very accurate and dont let the hype fool you, gas pistons have their own set of problems. I suggest checking out www.m4carbine.com a lot of guys over there are very technical and they have a lot of experience.

sorry www.m4carbine.net

The idea was to be installed under the handguard in almost the same plane as it is now. Protected between the barrel and handguard. This is just a theoretical excersize on improving the accuracy of the gas piston setup. I don't have any gas piston ARs. I only have the regular style.

Just running with a discussion I had about making a gas piston AR without the effect it has on stressing the barrel.

Scott

tell you guys what, i can turn my gas piston on and off so as soon as i can get back to the range ill try some test with it on then off and see if the point
of aim and impact change

I have yet to see the hard facts that adding a piston to your rifle will either make the rifle's accuracy decrease or increase, I do know that my LWRC M6A2 16" is fairly accurate(moa roughly, sometimes better, sometimes worse) with 69gr SMKs that I load through a dillon 550 with 24.5 grains of RL-15. I am currently talking with Steve from satern machining about building a 20" 6.5 grendel barrel to work in conjunction with a PWS piston system and a Vltor 12" monolithic upper. LWRC also makes the SABR in .308 that really drives tacs. The true benefits that I find to a piston are reliability with fine dust and as I write this to you all from a JSS in Iraq, that stuff gets in anywhere...ask any gunner or air guard on a stryker, they'll tell ya as well.
I plan on having this thing shoot sub moa or better with hand loads. As far as gas pistons having their own set of problems? Like what? m240B is gas piston operated, same with the m21...worked in plenty of sand storms...wish I could say that about the majority of the M4's/m16's in the platoon/co/battalion. I'm not here to bash anyones comments or to flame anyone, but in reference to piston systems, which ones have their flaws that regard directly to the piston and not feeding/ejecting issues that may be associated with a piston driven gun? What are you looking for as far as accuracy? shoot a criminal in the head from 300 meters that is standing behind a hostage he is holding at knife point/5 shots in 1 hole at 100 meters/110 yards?
Also, it takes me about 5 to 10 minutes to clean my personal piston driven rifle as apposed to the 2 to 3 hours plus saturation time of the oil clear its way out of the pours it does for my issued m4...just some food for thought, right? shenanigans

I am in no way saying that the AR is better with a gas piston. I currently don't own one and have no immediate plans on buying one. It would be interesting to install a gas piston setup and compare its function.

For problems with a gas piston, I was just referring to they have different parts that wear out than a gas operated system.

The whole idea behind what I was thinking is an effort to leave the barrel free floated and unaffected by any other force. People switch from standard handguards to free float forearms to remove stresses off the barrel to increase accuracy.

By free floating the barrel and then adding a gas piston system to it, there is now a force applied to the barrel that has an outside possibility of applying forces to the barrel like standard forearms could.

The concept of attaching the gas piston to the free float forearm would leave the barrel free floating and unaffected by any outside force. The gas piston attached to the inside of the forearm could still be inline with the current location of the piston attached to the barrel.

My questions were has this been tried before and would the forearm, barrel nut, and receiver handle the forces applied to the forearm instead of the barrel. It would make for a gas piston AR with the barrel floated and unaffected by any outside force. Then by attaching the gas block to the gas piston by way of a gas tube, the gas piston can be placed closer to the reciever making the operating rod shorter. Whether the op rod is attached to the bolt carrier or piston.

I know it's a crazy idea. It probably isn't even worth testing. I was just wondering if the forearm, barrel nut, and receiver are able to take those forces applied to the forearm instead of the barrel.

Scott

I am saying that the gas piston makes the AR platform better...parts wear out? maybe after 5 or 6 barrels wear out...maybe? Mine has thousands of rounds through it, still tight, runs like a champ.

As far as free floating...yes, agreed, less stress = greater accuracy. Hence bolt action rifles being the most accurate.

Has what your asking been done before? not sure if it has been, not to sure about what the Viron system either...the web site is very vague with its pictures.

I will tell you this though, I am putting together a 20" piston operated 6.5 grendel AR with the help of the very nice people from Satern Machining. I will give you an in depth report on its accuracy in comparison to my FN Patrol Bolt XP in .308 and my Badger Ordnance M2008 in .260 remington ackley improved as soon as I get back state side in about 5 months to try to put these piston rumors to rest, either fact or fiction.

I'm sure your set up that you are talking about could work if the parts that will take the force are made strong enough and maybe redesigned slightly.

what piston systems are you most familiar with? quite few companies are making them now, all different in one way or another.

One thing to remember. The impingment systems uses up to 18% of the gas pressure to work the bolt but the gas tube flexes minimally while firing. The piston systems use substantially less gas but the rods have their own flex and torsion that may (or may not) exhibit any accuracy affecting issues on the barrel. Velocities should increase to a POI difference at range. Accuracy?? More tests should be done. Will I? Nope I'm broke and don't work for any cool companies with such products. But one thing is predominantly obvious. It is somewhat of a pleasure to clean a piston gun!! Jmho

I have yet to see the hard facts that adding a piston to your rifle will either make the rifle's accuracy decrease or increase, I do know that my LWRC M6A2 16" is fairly accurate(moa roughly, sometimes better, sometimes worse) with 69gr SMKs that I load through a dillon 550 with 24.5 grains of RL-15. I am currently talking with Steve from satern machining about building a 20" 6.5 grendel barrel to work in conjunction with a PWS piston system and a Vltor 12" monolithic upper. LWRC also makes the SABR in .308 that really drives tacs. The true benefits that I find to a piston are reliability with fine dust and as I write this to you all from a JSS in Iraq, that stuff gets in anywhere...ask any gunner or air guard on a stryker, they'll tell ya as well.
I plan on having this thing shoot sub moa or better with hand loads. As far as gas pistons having their own set of problems? Like what? m240B is gas piston operated, same with the m21...worked in plenty of sand storms...wish I could say that about the majority of the M4's/m16's in the platoon/co/battalion. I'm not here to bash anyones comments or to flame anyone, but in reference to piston systems, which ones have their flaws that regard directly to the piston and not feeding/ejecting issues that may be associated with a piston driven gun? What are you looking for as far as accuracy? shoot a criminal in the head from 300 meters that is standing behind a hostage he is holding at knife point/5 shots in 1 hole at 100 meters/110 yards?
Also, it takes me about 5 to 10 minutes to clean my personal piston driven rifle as apposed to the 2 to 3 hours plus saturation time of the oil clear its way out of the pours it does for my issued m4...just some food for thought, right? shenanigans

the m21 had an expected accuracy of about 2 moa. thats on par with the best svd and ammo combo. i read someone (in fact, quite a few) on this forum managed to get <.4 moa at 100 yards. yes it was handload, but even les baer can get it to shoot below .5 moa with factory stuff. the m240b is an MG. accuracy doesn't matter too much. still, i agree that for military service a 2moa rifle that is much more reliable and easier to clean is better than a less reliable rifle that can shoot .5 moa on the basis that not everyone can use the potential (especially under stress) and combat is mostly <300 m and 98% < 800 m (we are hunting a human size targets).

but... i guess vstarnd is talking about how accurate one can get from a piston for 1 hole groups and whether he could match a DI with it. if yes, then im on board the train. but i don't have the funds for such R&D so best to leave it to the big guys with deep pockets.

I was asking if such a set up could be made or if materials are strong enough or if it's just too impractible to even try. My curiosity was in the design and material strengths and flaws or if it's already been tried.

I was curious about design concept, flaws, and if there is nothing to gain in such a design. I in no way am able to bring the concept to a working design. I was just wondering if the materials could handle the stresses and if anything could be gained.

Scott

Why not just simply use the viron system? if it works... If I had unlimited funds (US govt comes to mind) I'd try that and your method, and see which one performs better.
What the heck is the viron system? :o

My AA Piston systom is just under a MOA at 100 yards with fine tune reloads. Have not tried factory ammo.

I have a 14.7" 5.56 LWRC that shoots 3/4 MOA at 100 yards consistently with hand loaded 77gr SMK . Furthermore I and just received my 18" AA Piston setup witch I am eager to put threw its paces as well. Though to comment on the original concept, the Gas Piston system is mounted directly against the Mega Monolithic upper receiver, which could reduce in inconsistency in forces acting on the rifle. In addition a friend of mine who has shot his 22'' 6.5 Grendel with and without the piston, he has noticed only a noticeable point of impact difference must like a suppressor. He has not noticed a decrease in accuracy due to the Gas Piston, again he is using quality components, Adams Arms Setup mated against a Vltor VIS 3.