Looks well made…Matterial wise how would you compare it to the POF system?
Sounds logical.
Anyone know if the piston mod would affect accuracy?
Of course. This is the downside to Piston’s. In a DI AR, the bullet has left the weapon before the weapon moves. This is not the case with a piston AR.
C4
Has anyone compared it against a DI gun with similar components to see how much it affects accuracy?
It is generally VERY hard to setup two guns the exact same way (one with a piston and one without). You can get close in some instances though.
I personally think it is safe to assume that a piston system will cause between 1/4-1/2 loss in accuracy and maybe much more depending on the system.
My hope for the PWS system is that there is little to no loss, but we shall see.
C4
With my two LWRC: 6.8 and 5.56, it shoots 3" to 1.5" groupings at 300 yards which is dependent on the ammo of course…
When checking accuracy, how many rounds are you firing?
C4
For a carbine type rifle I don’t think anyone will find that pistons effect practical accuracy enough to matter. I mean damn the optic I’m using is a 2MOA dot meaning it’s covering approximately 2 inches of the target at 100yds, many guys are running 4MOA dots. On my best day offhand with a 2MOA optic I won’t ever shoot 2" groups at that distance anytime soon. So I find the point of piston accuracy moot.
Piston accuracy vs. DI accuracy? On a rifle with a variable power scope like a 4.5-14x or 6.5-20X then yes there I think a good shooter will most likely see a difference.
Good point Rob. You cannot figure out a weapons accuracy when you are shooting a non-magnified dot optic.
People should not be worried about accuracy if they are running a chrome lined barrel, shooting a dot optic, using Mil-Spec ball and a 8lbs trigger.
C4
Sounds like pistons and chrome barrels on fighting guns = just fine. On a rifle with more precision in mind DI and SS barrels sound optimal.
I think so. Chrome lined and a piston system goes together well.
C4
The Piston Operated AR uses less gas to cycle than a DI. So how is the bullet still in it’s barrel?
If I’m not mistaken, this was proved by LWRC some time ago and that accuracy is the same. This is written in an effort to see if there is something I have missed, not to start an argument.
A better way for me to say it is that the weapon is basically starting to “vibrate” and move by the time the bullet leaves. Remember that gas is in FRONT of the bullet, sides of the bullet and behind the bullet.
I am sorry, I don’t really follow what LWRC does or says. All I know is that I have never gotten a piston weapon to group (using 10rds) as well as a DI AR can. If you understand what the piston is doing (really understand), you would realize that there is no way for it to be as accurate as a DI weapon.
C4
Hello all,
I don’t mean to come in hard on my first post but as a 16inch upper POF owner with the rifle giving me some very good accuracy so far even though I haven’t pushed it for best yet, the piston effecting the accuracy issue by moving before the bullet has exited the barrel doesn’t seem right to me.
Especially at the velocity a normal 5.56/.223 round exits the barrel.
Recon posted this in the AR tech section from Armalite’s site discussing old Army testing done on the M1 and M14 that the bullet is quite far away from the barrel before the piston starts moving as example.
With the from muzzle velocity of 5.56x45mm very close to 7.62x51mm Nato and gas system not that far off in length, I just don’t see it as likely.
Is there some testing that has been done on some current piston AR platforms I’m missing?
Actually if you read it carefully, they do mention that the weapon is doing something before the bullet leaves the weapon (vibrating, parts moving, etc). They also stated that the AR platform is superior to the piston system in regards to operating in a sandy environment. We all know that this just isn’t the case. So I wouldn’t put to much stock into what that “tech file” says. 
If you want to see what kind of groups your weapon is capable of, fire 10rds at 100yds. Anything less than 10rds will not give you an accurate picture of the weapons accuracy capability.
C4
The info definitely seems a bit out of date and I do only put so much stock in it, but the military testing data if correct is still a fair base I think.
As their talking here,
It is more likely that the imbalances of the piston, operating rod, cylinder, and other parts
hanging on the barrel produce disruptive vibrations as the bullet exits the bore.
is a wonder to me as it wouldn’t necessarily be the same in every piston action as the designs are different. One could be less of a disruption than another with only in depth testing to really see more about it.
I will get around to giving the rifle a good 10 shot accuracy testing one of these days.
You also need to look at where the gas piston is in regards to the length of the barrel. If you are using a 16" barrel with a carbine gas port then that is most likely much different config than what they tested. That .Mil report is also very dated and we really don’t know how and what was tested (if it was even a formal test at all).
C4
Understandably the barrel length in accordance to where the gas system is positioned on the barrel with it’s length would leave more distance for the bullet to travel after the gas system was reached, but that testing would seem reasonable to me with 15 feet of distance from an M14 with a traditional fullsize having a 22 inch barrel with it’s mid placed gas cylinder to compare to even today.
Having an accurized full length M1A in a CrazyHorse configuration too and my POF 16 with it’s carbine placed gas system it’s very close between the two.
At 15 feet of bullet distance from the M14 and similar bullet velocities between 7.62x51 and 5.56x45, it just seems unlikely the bullet would be still in the barrel when the piston/op rod starts moving.
It seems more likely the distance might be less from the barrel on the POF, but still many feet away just the same.
Thank you for your thought and experience on the subject.
I really don’t think it is unlikely at all as there is gas all around the bullet (including infront of it).
C4