Piston Driven AR

Eddie Gunks · Jan 4, 2018

togmaster said:
Are there other or better alternatives?

SCAR16
LWRC

Calculon · Jan 4, 2018

Calculon · Jan 4, 2018

togmaster said:
Have you used one of these kits?

I haven’t used the piston kit but I have used the adjustable gas blocks with bleed off valve and they have been great so far. The excess gas goes out the valve vs just being blocked off. In theory less wear and tear on the adjustment screw so should have longer service life than a standard adjustable block.

.750" Adjustable Gas Block, Bleed Off - Solid, Melonited

EDIT - Have thought about using a piston retrofit but so far can’t see the need for it. Direct impingement system seems to work just fine.

BDSKJCHRIS · Jan 4, 2018

Bullet Guy said:
SCAR16
LWRC

x2 for LWRCI, they are well worth the money, not to mention you can catch their uppers on sale for 20-25% off a few times a year.

My first AR was an LWRC M6A2-SPR and that's what got me hooked on piston AR's

togmaster said:
Have you used one of these kits?

I have built 4 rifles using superlative arms piston kits, 2 rifle length systems on 20" bcm barrels, 1 mid length system on a 16" fn barrel, and 1 carbine length on a 16" KAK .300blk barrel.

all of them work perfectly except for the .300BLK, which i expected when i was building the rifle. Using hornady black 110grain supersonic ammo, it will fire, eject, and feed the next round with no issues, but it does not lock open on an empty magazine. For shits and giggles i tried running some hornady 208grain amax subsonic loads through it, it fires and extracts but will not eject the spent case due to short stroking. not a big deal as i don't plan on running subsonics unless i can escape NY to a state that allows suppressor ownership.

I do believe that i could get it to run super sonic loads 100% reliably if i were to replace the buffer spring with the nemo arms .300 blk carbine spring, (lighter buffer spring meant to increase reliability in 16" .300blk guns with carbine gas systems), or changing out the piston return spring for a lighter one. the owner of Superlative arms is developing a dedicated .300 BLK piston kit.

but on the 5.56 rifles, the superlative arms kit has been every bit as reliable as my LWRC has been.

Mosinitis · Jan 4, 2018

AR gas system is one of the advantages, why go back to inferior technology.

Mosinitis · Jan 4, 2018

togmaster said:
I don't necessarily think it's inferior. Might even have some advantages. And if you have to ask why build an EAR you shouldn't ask. Lol

Yes, it is inferior. The piston is moving while the bullet is still in the barrel. Not the best thing for accuracy. Not just my opinion. For recreational plinking anything will do,
but it is still inferior.

BDSKJCHRIS · Jan 4, 2018

Mosinitis said:
AR gas system is one of the advantages, why go back to inferior technology.

SCAR-16S and 17S, ACR, Sig Sauer MPX, CZ 805, hk 416/417, beretta ARX-100, the list goes on...plenty of new rifles with great reliability, (some that have been combat proven for a while now) not to mention systems like the M249, M60, MK48, MK46, M240.

IDK if i would declare external short stroke pistons (or pistons in general) to be inferior technology.

Mosinitis · Jan 4, 2018

Well maintained AR is very reliable. In terms of shooting a rifle at meaningful distances, you can't beat AR gas system. No one is shooting piston AR's at Camp Perry.

BDSKJCHRIS · Jan 4, 2018

Mosinitis said:
Yes, it is inferior. The piston is moving while the bullet is still in the barrel. Not the best thing for accuracy. Not just my opinion. For recreational plinking anything will do,
but it is still inferior.

i have yet to see anyone present demonstrable evidence that a piston negatively impacts accuracy or repeatability. my 20" SAM-R imitation has given me consistent sub-MOA groups out to 300 yards and i Know i am not the greatest shooter.

if muzzle velocity for MK262 from a 20" barrel is 2750 FPS and the gas system is 12" long that means the bullet is only in the barrel for another .0002 seconds. it would be less for m193 or m855. how much do you think the piston is moving in 2 Ten-Thousandths of a second? i would bet the bullet is long gone by the time the bolt begins to rotate and unlock.

not to mention i have yet to see anyone give an explanation as to how added heat and carbon fouling is better for moving parts.

Mosinitis · Jan 4, 2018

Your mind is made up based on the time and money you invested, I don't expect to change your mind. People who are serious about accuracy and shoot beyond 50 yards don't convert AR's to piston.

BDSKJCHRIS · Jan 4, 2018

Mosinitis said:
Well maintained AR is very reliable. In terms of shooting a rifle at meaningful distances, you can't beat AR gas system. No one is shooting piston AR's at Camp Perry.

an occasionally oiled Piston AR is more reliable.

I would consider 300 yards sub MOA to be meaningful i am sure it will perform great at well over 500 yards.

Maybe nobody uses them at camp perry because they have never been issued as a service rifle so until 2016 the CMP did not allow Piston Operated AR-15 rifles to be used in matches.

Nobody in the US military was ever issued an FN FAL but that doesn't mean the M14 is superior.

BDSKJCHRIS · Jan 4, 2018

Mosinitis said:
Your mind is made up based on first hand experience with both DI and Piston Rifles, I don't expect to change your mind. People who are serious about accuracy and shoot beyond 50 yards don't convert AR's to piston.

FTFY

lol, I bought 1 piston rifle, it was my only rifle for almost 4 years, it works fine,gives me good results, and if i wanted i could have sold it and profited 150% when the safe act passed, the rifles i have built were all built for the same price as they would have cost me to go with Direct Impingement. I still have DI rifles as well. if your rifles accuracy goes to shit past 50 yards, don't blame the piston or the rifle, buy ammo and practice.

the fuddlore is strong with this one.

SomeSoldier · Jan 4, 2018

Bullet Guy said:
SCAR16
LWRC

I own a LWRIC and it is an amazing piece of equipment.

Mosinitis · Jan 4, 2018

What did you win with piston AR, except pissing contests on the web? Public range commando.

Onegunnotenough · Jan 5, 2018

togmaster said:
With the extended cold weather I'm finding a lot of extra time on my hands so I think it's time to scratch the build itch once again. I have a few things I'd like to do but I'm thinking of a piston driven upper. I've been looking around and it seems that Adams Arms has what I'm thinking of. Piston Kit - Standard Picatinny Block I haven't decided on the specific stripped upper yet. It will most likely be mated to a crowned mid length barrel and a free floating rail.

Has anyone used this in a build? Are there other or better alternatives?

I did one on my SCR, KIT FROM FIGHTLITE, absolutely makes a difference, keeps barrel much cooler.

Jsmegs77 · Jan 10, 2018

Onegunnotenough said:
I did one on my SCR, KIT FROM FIGHTLITE, absolutely makes a difference, keeps barrel much cooler.

Piston setup works with SCR bolt carrier? What did you use? Plotting out a SCR build and looking at options here...

Onegunnotenough · Jan 11, 2018

Jsmegs77 said:
Piston setup works with SCR bolt carrier? What did you use? Plotting out a SCR build and looking at options here...

Fightlite makes a piston kit. Call them or look on optics planet. I used Daniel defense furniture so I had to do some mods for it to work,but if you don't want to customise they sell a furniture kit that fits over it. It's but ugly.

Phauxtoe · Jan 11, 2018

piston driven....
Yea its called an AK!

Onegunnotenough · Jan 11, 2018

Jsmegs77 said:
Piston setup works with SCR bolt carrier? What did you use? Plotting out a SCR build and looking at options here...

They give you a new bolt carrier in the kit

Piston Driven AR

.450/400 Nitro Ex

.338 Win Mag

.308 Win

.450/400 Nitro Ex

.450/400 Nitro Ex

.308 Win

.40 S&W

.338 Win Mag

.450/400 Nitro Ex

.450/400 Nitro Ex

.338 Win Mag

.40 S&W

.338 Win Mag

.40 S&W

.338 Win Mag

.40 S&W

.40 S&W

.450/400 Nitro Ex

.338 Win Mag

.450/400 Nitro Ex

.40 S&W

.308 Win

.40 S&W

.338 Win Mag

.40 S&W