Piston Upper AR

ChaseReynolds · November 10, 2012, 05:41 PM

Looking to build my first AR, I am not sure if I can do a piston driven upper but I hear piston driven is the way to go. I want my AR to be 7.62. If anyone has any advice or has done this already please fill me in. Thanks

Sweet Shooter · November 10, 2012, 07:07 PM

Pistons are definitely being proving. I'm not sure how reliable the x39 is in the AR platform, but this is an eye opener with the 5.56 piston.
-SS-

chris in va · November 10, 2012, 07:10 PM

You want 7.62x39 or 51?

Quentin2 · November 10, 2012, 07:46 PM

Quote:

...I hear piston driven is the way to go...

Who do you hear that from? Don't believe everything you hear!

RamItOne · November 10, 2012, 09:29 PM

Quote:

Originally Posted by ChaseReynolds

I hear piston driven is the way to go

Yeah the old way sucks, thats why we lost Vietnam.

Either system works very well. There is another thread here about cleaning or not cleaning the gas tube. I'm in the "never camp", 1,000s of the best crap coming out of the eastern block and no issues.

Now your BCG stays cool to the touch with a piston system, yeah cool but that wouldn't sway me either way.

Good luck

ChaseReynolds · November 11, 2012, 12:09 AM

Well, alot of the shooting magazines are saying that piston driven is the future. I want to shoot 7.62x51. I think that is what the SCAR 17 shoots. I just want the fire power without the SCAR premium.

Theohazard · November 11, 2012, 03:35 AM

Quote:

Well, alot of the shooting magazines are saying that piston driven is the future.

That may be true, but many people - including myself - prefer a direct gas system for an AR platform.

Quote:

I want to shoot 7.62x51. I think that is what the SCAR 17 shoots. I just want the fire power without the SCAR premium.

When you say you want to build your first AR, do you meant its going to be the first AR you own, or just the first AR you build yourself? If it's your first AR, I say go with 5.56; in my opinion, the main reason to go with 7.62 is if you want to hunt larger animals with it, and/or you're planning to shoot past 300 meters on a regular basis. At ranges less than 300 meters against two-legged and smaller four-legged animals I much prefer the 5.56.

bedlamite · November 11, 2012, 07:14 AM

Quote:

Originally Posted by ChaseReynolds

Well, alot of the shooting magazines are saying that piston driven is the future.

Their job is to sell ad space in next months rag.

RT · November 11, 2012, 07:44 AM

You know that you can't build a 7.62x51 using an AR-15 lower, right.

Sweet Shooter · November 11, 2012, 11:37 AM

Guy at the range showed me his piston-driven AR interior after ~500 rounds the oil in there was still clean. The bolt back was immaculate. The only mess was where the exhaust comes out under the hand guard and blowing on the scope lens.

He also said he'd taking it back out to experiment and going back to DI he noticed a definite decline in inaccuracy. So he put it back in. That is the other way around to what I would expect.
-SS-

Eghad · November 11, 2012, 12:03 PM

Piston Rifles are not new. They have been around for years. The only problem I have with buying piston in an AR15 is that the systems are proprietary. If something breaks in the piston system you are going to be down till you get the part in. Plus there is no clear cut advantage for it over owning a DI AR15. You can build an AR10 in 7.62 but the ammo costs are higher.

Eghad · November 11, 2012, 12:09 PM

"Yeah the old way sucks, thats why we lost Vietnam."

don't think so.

The reasons the AR16 didn't work in Vietnam were self inflicted. Having said that the AR style rifle has worked all of that out and it is a reliable system now. I started out in 1975 with the M16A1then went to the M16A2. Never had any reliability issues with any of them I was issued. I was still shooting Expert when I retired in 2004.

TMD · November 11, 2012, 12:15 PM

Quote:

Piston Rifles are not new. They have been around for years. The only problem I have with buying piston in an AR15 is that the systems are proprietary. If something breaks in the piston system you are going to be down till you get the part in. Plus there is no clear cut advantage for it over owning a DI AR15. You can build an AR10 in 7.62 but the ammo costs are higher.

This should be your biggest concern if your building one. If you get a kit from some fly-by-night company and they go under your screwed if you ever need a part.

Now back to the piston v. DI debate. I have 7 AR's and only one is a piston model. Its an Adcor B.E.A.R.
Pro's: Very nice rifle, shoots great, bolt seem's to never get dirty.
Con's: A little bit heavier, louder, cleaning under the handguard is a pain, expensive.

Theohazard · November 11, 2012, 01:19 PM

Quote:

He also said he'd taking it back out to experiment and going back to DI he noticed a definite decline in inaccuracy. So he put it back in. That is the other way around to what I would expect.

There are so many other factors that can affect accuracy besides just which gas system the rifle uses. There are plenty of piston rifles that are more accurate than many DI rifles; however, that's in spite of - not because of - the gas system.

If you managed to make two rifles that were identical in every way possible, except one had a piston and one was DI, the DI would be more accurate. The accuracy gap wouldn't be very large, and as gas systems improve that gap shrinks even more, but it's still there.

Sweet Shooter · November 11, 2012, 05:21 PM

Quote:

Theohazard
There are so many other factors that can affect accuracy besides just which gas system the rifle uses. There are plenty of piston rifles that are more accurate than many DI rifles; however, that's in spite of - not because of - the gas system.

I'm talking about the same rifle—changing between the two systems. I never said that generally one system was better than the other, I'm giving an example where the piston driven system was.
Very aware of what can and can't effect a rifle's accuracy in general terms.
-SS-

Eghad · November 11, 2012, 07:58 PM

http://www.nxtbook.com/nxtbooks/nra/ssusa_201102/#/20

DI had an edge in the accuracy department. When you add more moving parts to something it will probably have an effect of the harmonics as the article suggests. A gas Piston gun can be tuned as the article suggests. However, this won't be free and will add to the cost of the rifle.

Crow Hunter · November 12, 2012, 08:49 AM

One of the advantages of the AR system is that the lower is the "gun".

If you get a piston upper, and you later can't get parts or decide you don't like it, you can always switch to a DGI by just swapping uppers.

That being said, the pistons will always be more expensive than the DGI for a small reduction in cleaning time. I guess it depends on how valueable your personal time is.

Now if you are planning on coming up out of the water like a SEAL and shooting immediately or going with really short barrels and firing full auto, then a piston has some advantages over DGI in those situations.

November 10, 2012, 05:41 PM	#1
ChaseReynolds Senior Member Join Date: March 29, 2012 Location: Fort Riley, Kansas Posts: 186	Piston Upper AR Looking to build my first AR, I am not sure if I can do a piston driven upper but I hear piston driven is the way to go. I want my AR to be 7.62. If anyone has any advice or has done this already please fill me in. Thanks

November 10, 2012, 07:07 PM	#2
Sweet Shooter Senior Member Join Date: June 17, 2011 Posts: 672	PISTONS Pistons are definitely being proving. I'm not sure how reliable the x39 is in the AR platform, but this is an eye opener with the 5.56 piston. -SS-

November 11, 2012, 11:37 AM	#10
Sweet Shooter Senior Member Join Date: June 17, 2011 Posts: 672	Piston Clean Guy at the range showed me his piston-driven AR interior after ~500 rounds the oil in there was still clean. The bolt back was immaculate. The only mess was where the exhaust comes out under the hand guard and blowing on the scope lens. He also said he'd taking it back out to experiment and going back to DI he noticed a definite decline in inaccuracy. So he put it back in. That is the other way around to what I would expect. -SS-

November 11, 2012, 12:03 PM	#11
Eghad Senior Member Join Date: May 28, 2005 Location: Texas Posts: 6,231	Piston Rifles are not new. They have been around for years. The only problem I have with buying piston in an AR15 is that the systems are proprietary. If something breaks in the piston system you are going to be down till you get the part in. Plus there is no clear cut advantage for it over owning a DI AR15. You can build an AR10 in 7.62 but the ammo costs are higher. __________________ Have a nice day at the range NRA Life Member

November 11, 2012, 12:09 PM	#12
Eghad Senior Member Join Date: May 28, 2005 Location: Texas Posts: 6,231	"Yeah the old way sucks, thats why we lost Vietnam." don't think so. The reasons the AR16 didn't work in Vietnam were self inflicted. Having said that the AR style rifle has worked all of that out and it is a reliable system now. I started out in 1975 with the M16A1then went to the M16A2. Never had any reliability issues with any of them I was issued. I was still shooting Expert when I retired in 2004. __________________ Have a nice day at the range NRA Life Member

November 10, 2012, 07:10 PM	#3
chris in va Senior Member Join Date: December 26, 2004 Location: Louisville KY Posts: 13,806	You want 7.62x39 or 51?

November 11, 2012, 12:09 AM	#6
ChaseReynolds Senior Member Join Date: March 29, 2012 Location: Fort Riley, Kansas Posts: 186	Well, alot of the shooting magazines are saying that piston driven is the future. I want to shoot 7.62x51. I think that is what the SCAR 17 shoots. I just want the fire power without the SCAR premium.

November 11, 2012, 07:44 AM	#9
RT Senior Member Join Date: September 9, 2000 Location: San Antonio, TX Posts: 2,194	You know that you can't build a 7.62x51 using an AR-15 lower, right.

November 11, 2012, 07:58 PM	#16
Eghad Senior Member Join Date: May 28, 2005 Location: Texas Posts: 6,231	http://www.nxtbook.com/nxtbooks/nra/ssusa_201102/#/20 DI had an edge in the accuracy department. When you add more moving parts to something it will probably have an effect of the harmonics as the article suggests. A gas Piston gun can be tuned as the article suggests. However, this won't be free and will add to the cost of the rifle. __________________ Have a nice day at the range NRA Life Member

November 12, 2012, 08:49 AM	#17
Crow Hunter Senior Member Join Date: January 27, 2012 Posts: 1,078	One of the advantages of the AR system is that the lower is the "gun". If you get a piston upper, and you later can't get parts or decide you don't like it, you can always switch to a DGI by just swapping uppers. That being said, the pistons will always be more expensive than the DGI for a small reduction in cleaning time. I guess it depends on how valueable your personal time is. Now if you are planning on coming up out of the water like a SEAL and shooting immediately or going with really short barrels and firing full auto, then a piston has some advantages over DGI in those situations. __________________ I am no longer participating in gun forums. Good luck.