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2/28/2015 8:01:41 PM EDT

Hey all

So im building an AR from scratch and I want to have a piston system instead of the gas system on a 12inch SBR

So here is my question where at on the barrel is the “gas opening” (not sure what its real name is) or how long of a piston system should I get like is there a chart or something saying you need this long of a piston for this long of barrel
2/28/2015 8:46:12 PM EDT
[#1]
Quoted:

Hey all

So im building an AR from scratch and I want to have a piston system instead of the gas system on a 12inch SBR

So here is my question where at on the barrel is the “gas opening” (not sure what its real name is) or how long of a piston system should I get like is there a chart or something saying you need this long of a piston for this long of barrel
View Quote


I respect wanting to build it from scratch, but why make life harder for this particular portion of the build.
If you buy a piston length barrel, the gas port will already come pre-tapped in the appropriate location at the appropriate diameter.
2/28/2015 9:48:08 PM EDT
[#2]
Quote History
Quoted:


I respect wanting to build it from scratch, but why make life harder for this particular portion of the build.
If you buy a piston length barrel, the gas port will already come pre-tapped in the appropriate location at the appropriate diameter.
View Quote View All Quotes
View All Quotes
Quote History
Quoted:
Quoted:

Hey all

So im building an AR from scratch and I want to have a piston system instead of the gas system on a 12inch SBR

So here is my question where at on the barrel is the “gas opening” (not sure what its real name is) or how long of a piston system should I get like is there a chart or something saying you need this long of a piston for this long of barrel


I respect wanting to build it from scratch, but why make life harder for this particular portion of the build.
If you buy a piston length barrel, the gas port will already come pre-tapped in the appropriate location at the appropriate diameter.



i would but i cant find any 12/12.5 inch barrels that come with a piston system i would love to get a kit that way like you said its already the right length and sizing and everything but the shortest one iv found is 14 inch
3/1/2015 1:33:54 PM EDT
[#3]
Did you look in the industry forum under Adam Arms?  They have thread about barrel length vs piston drive rod length in there.  That is where I started.
3/1/2015 1:44:36 PM EDT
[#4]
Quote History
Quoted:
Did you look in the industry forum under Adam Arms?  They have thread about barrel length vs piston drive rod length in there.  That is where I started.
View Quote



no i did not still pretty new to this forum thing. thank you tho ill check it out
3/2/2015 12:04:33 AM EDT
[#5]
LMT makes a 12 inch piston barrel, but I think your going to need one of there MRP uppers to throw the barrel into.
3/2/2015 10:34:24 AM EDT
[#6]
I think some people in this thread are confusing "piston" and "pistol".

Most 5.56 barrels in the 12" range have carbine-length gas ports. And you can use them to build a piston or DI upper. The barrel is the same for either; what's different is the gas block, bolt carrier, and the parts that go between them.
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