Gas Piston Uppers

[sonnyt650]

Correcting somebody here, probably both: in either case the majority of the bolt/carrier momentum is derived through the axis of the barrel -- the gas port on the barrel is way too small to exert all that pressure. The only difference between DI and piston is that the piston physically pushes the carrier back until the bolt unlocks from the receiver, versus the gas flowing down into the bolt carrier pushing the bolt "piston" which twists and unlocks from the chamber. Said another way the piston unlocks the bolt by pushing at the top of the carrier, while DI unlocks the bolt by releasing gasses inside the carrier itself.

[sonnyt650]

BTW: don't y'all with piston uppers still have to clean the chamber? I do, just not the bolt carrier and receiver itself.

[Droppin Deuces]

Yeah, the chamber and occasionally the end of the rod where the gas squirts out. That's about it.

[Average Joe American]

I dont get the whole "piston systems have more moving parts to break" argument.


Here is my Stag model 8 piston system. Very simple and my Stag only weighs 6lbs 9oz. Its not "heavy" feeling but I could be stronger than the average person lol.

[Austin794]

I don't own any piston guns but if I had to pick one. Primary Weapons Systems (PWS) has awesome piston uppers. I've personally seen a 10" in none stop full auto action a couple of weeks ago at a demo shoot, and it ate everything we could feed it.

[Don29palms]

How are the lowers marked on the left side??

Thinking you MAY have a banned-by-name problemo', possibly.

-hanko

That's what I was thinking.

[Barabas]

He's good, fellas.

[17+1]

I don't buy the accuracy part. Accuracy has to do with the shooter, and as long as you can hold a group with that rifle there should be no problem and if you cant hold a group then there is something wrong with the rifle anyways. Consistency is accuracy.

As far as the second part, you do realize there is a gas tube that runs above the barrel (in the same place the piston is) that pushes back the carrier in the same spot as a GP rifle right? It is not blowback, which I believe you are trying to describe (correct me if I'm wrong).

If it's just as accurate, why aren't people using a gas piston setup to shoot matches?

The gas tube redirects the gas from the barrel to the action in the upper receiver. It is not a chunk of steel and a heavy housing exerting outside forces on the barrel. There will be some slight forces from the FSB, but nothing like having a moving piston system bolted to the barrel. If you don't understand the concept of barrel harmonics and resonance none of this would make any sense to you.

The carrier is not pushed back at the gas key, the key is what channels the gas into the interior of the carrier, into the area right behind the bolt tail.

I understand how an AR works, which is why I realize a gas piston is going to degrade the AR's strongpoints in an effort to make it easier to clean for lazy shooters.

[BigBamBoo]

..........

[sonnyt650]

...which is why I realize a gas piston is going to degrade the AR's strongpoints...

Look at the last post: your typical AR shooter isn't going to ever experience a 3/4 moa group which works out to a .75" group at 100 yards, and this was done with a piston upper. I'll propose there are so many other things that are required from excellent ammo and a wind-free day that have far more impact on the groups than does a piston. Sure I wouldn't want this on a bench-rest rifle where winning is on the order of tenths if not hundredths of an inch, but a piston doesn't transform an AR into an AK.

[Predator]

Personally I got an 18" POF because that is what I wanted. If you want a GP, cool go for it. If you're a hater then don't. It's as simple as that. I don't get why people need to rip on other systems ((Trolls ))

[IsaacGlass]

Thanks everyone for your input. This gives me many ideas as to how I want to build my AR-15. Later, I would like to put together a 6.8 rifle.

He's good, fellas.

Righto!