Piston vs. GI

[tsmysak1]

Hi all,

Looking for some real evidence either way for or against piston guns vs. gas imping.. impeng.. hell ....GI guns.

I have heard several people say the GI guns are more accurate (AR style). I was wondering if there is a shred of evidence on this.

Would really like to hear from someone who has shot both side by side.

 

[cosermann]

I was wondering if there is a shred of evidence on this.

One way to compare the two systems might be to compare what has to be done to an M1A vs. an AR to get it to the point where it can be used in a high power match, AND what it takes to maintain that level of accuracy.

One significant difference between direct impingement and gas/piston systems is the amount of action mass that moves after you squeeze the trigger. Mass that has the potential to throw off shots.

 

[mettle]

I've got an XCR I'll let you run against whatever.

 

[tsmysak1]

I've got an XCR I'll let you run against whatever.

Heard good things about the XCR. Have you got any groups to share?

 

[mettle]

Heard good things about the XCR. Have you got any groups to share?

No, I can make some though.

I need to add: the rifle is interesting, the barrel secures solid enough that you may notice a very very very small POI, if any wen you remove it and reinstall it. Swapping barrels really is easy, and can allow one to use the same scope settings. I know a couple fellows that just swap caliber kits and run the Aimpoint at the same dial, just move POA for the different bullet travel.

I think Shooter521 may have posted on here about how some of the AR 'kits' to run a piston in DI guns are failing b/c of the piston being too weak for the work. Someone posted that anyways. You may as well buy a complete piston gun, and I'm not pushing XCR on you, it has weak points; rather than trying to retrofit a regular DI gun into a piston gun.

That being said, I'd love to have a POF. My XCR has a LOT of features built in that don't have to be added later though. Goods and bads with all things.

 

[tyler34]

XCR here as well, but not because it was a piston gun it was just a better deal at the time I bought it. without starting a pissing match about why one is better than the other I will tell what I know about them. I will not include accuracy as I don't feel it is valid because the differences are so minute unless your a uber pro comp shooter.

piston gun:

more mass cycling
cleaner
cooler temp. wise
less stress on the bolt
parts are less widely available
can be pricier
retrofit kits are not reliable compared to guns designed to be piston guns
in the xcr's case less parts= less chance of failure
most reputable brands offer caliber interchangeability
adjustable gas system's(really only good for suppressors)

personal opinion- piston guns designed to be piston guns from the ground up ARE more reliable than DI guns(retrofit kits are crap and not better). reasoning- the most reliable gun in the world(AK47) is a piston gun.

direct impingement-

ubiquitous, they are everywhere and extremely popular
proven design
let your imagination guide you when it comes to parts and accessories
cheaper
can be finicky if not lubed well, not always but enough for it to be a bullet point
more parts and smaller parts
dirtier

personal opinion- I don't have anything bad to say about them other than they can be finicky/malfunction if not properly maintained. and buy quality or build quality guns, not all brands are equal and it DOES make a difference.


I will also extend an offer to shoot my gun so you can help in your decision making process.

 

[ihateiraq]

what about the new ruger? i really wanted a piston gun, but that was the only other one i could find besides the original sig556. i just couldnt bring myself to plop down 2g on a rifle made by a company that primarily makes $500 pistols.

 

[tyler34]

what about the new ruger? i really wanted a piston gun, but that was the only other one i could find besides the original sig556. i just couldnt bring myself to plop down 2g on a rifle made by a company that primarily makes $500 pistols.

I played with one at the indy gun show and it looked and felt solid. other than that your guess is as good as mine.

 

[ihateiraq]

it did feel pretty solid, but im sure the titanic, or the hindenburg did as well.

 

[kevinj110]

Wait so why are the Adams Arms and CMMG kits crap. I think they perform wonderfully

 

[tyler34]

Wait so why are the Adams Arms and CMMG kits crap. I think they perform wonderfully

they are giving real piston guns a bad name. DI guns weren't designed for this type of gas system if they were they would already be piston guns. kind of like my jeep if I lift it it changes the geometry of the driveline components because it wasn't designed to be lifted making certain parts more prone to failure. (not the greatest analogy but the closest thing I could think of off the dome)

 

[Disposable Heart]

Not only that, but they are usually not properly installed and can batter the crap out of your reciever and cause unusual wear patterns. Moral of the story: if its a DI gun, keep it DI. If its a piston gun, keep it piston.

Either system works great, no matter what. If properly designed and built correctly, they will give the user worryfree operation. DIs are a bit "dirtier" in the reciever, but then piston guns add complexity (though it properly designed, its not an issue) and still have to be cleaned.

Its a big hurrah about nothing. If its a quality rifle, it should not matter what the operating system is. The AR platform works perfect with a DI system. Other designs like the XCR, AK, etc... work perfect with a piston system. Some ARs work great with a piston system. Who cares? Well, Piston ARs are a bit more expensive, but are usually a higher quality rifle anyways...

WHO CARES?!

 

[mettle]

Wait so why are the Adams Arms and CMMG kits crap. I think they perform wonderfully

I'd like to try 1 or 2 for plinking purposes, which do you own? Have you had one in a course before?

Here is a long thread on AR.15 that one may find interesting about the manufacturer's of .22 kits.
22 Conversions, Dedicated 22's, 22 Builds, Range Reports, Ammo and More. Ever Evolving..... - AR15.COM

That being said, if 1 did not buy a piston gun the .22 kits could be implemented with the rifle just for 'range and admin' work.

 

[tsmysak1]

It is probably left up to the consumer if the piston is worth the extra money or not. I was given the impression that pistons are not nearly as accurate. Seems no one has really tried them out.... I have gotten insane groups with DI guns. Even shot a couple of 2's at 100 yards. I guess I would be disappointed if they only shot 1 inch at 100.

 

[mettle]

Not only that, but they are usually not properly installed and can batter the crap out of your reciever and cause unusual wear patterns. Moral of the story: if its a DI gun, keep it DI. If its a piston gun, keep it piston.

Either system works great, no matter what. If properly designed and built correctly, they will give the user worryfree operation. DIs are a bit "dirtier" in the reciever, but then piston guns add complexity (though it properly designed, its not an issue) and still have to be cleaned.

Its a big hurrah about nothing. If its a quality rifle, it should not matter what the operating system is. The AR platform works perfect with a DI system. Other designs like the XCR, AK, etc... work perfect with a piston system. Some ARs work great with a piston system. Who cares? Well, Piston ARs are a bit more expensive, but are usually a higher quality rifle anyways...

WHO CARES?!

I've got above 5500 rounds in my XCR. Same bolt, same carrier, same op rod, same trigger group. I've had to replace the firing pin and hammer spring, that's it. It has required less, and that is what I like. Less work, less cleaning, less maintenance. (hardly any cleaning actually)

There are definitely plus's to other systems. I'm not saying the XCR is all the all, it's just ran for a hick like me... and that is saying something b/c I'm rough on everything. My lawnmower quick this week.

The OP might care.