ar upper/lower matching
- Thread starter Mamertine
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greyling22
Member
for the most part. some fit better and match colors of black better.
mgmorden
Member
Just to throw my post on the pile, it's my understanding that they pretty much all fit together. My lower is a Stag and my upper is a Del-ton and they mated up just fine.
Roughneck08
Member
All will gave slightly different tolerances and fit. My Rock River is tight and boy I love it, no play in it.
Quentin
Member
My S&W lower accepts my ArmaLite upper and a buddy's Bushmaster upper. Fit is fine.
But my ArmaLite upper won't pin on his Bushmaster lower - too tight - but I know it would work if we were determined. Neither of us felt like doing that.
But my ArmaLite upper won't pin on his Bushmaster lower - too tight - but I know it would work if we were determined. Neither of us felt like doing that.
They basically interchange fully on the .250 pins. It's the foundation of the industry - complete conformance to one design with no variance.
It goes so far that some will buy any barrel and any bolt, assemble, and fire, without a headspace check. That is risky, but done. No one recommends it. No one would do that with any other action. The Army tells you it can kill you in the TM. But some still do it. For best operation and accuracy, any barrel should be headspaced to the bolt it will use. Nonetheless, you see barrels alone, with the receiver extension already pinned and "set," for sale everywhere.
As said, you can get any kind of fit to the lower that the industry tolerance stack will create, from literally hammering the pins in, to a sloppy fit that shows a lot of daylight. What most completely get wrong is that the fit will not affect accuracy whatsoever. It's entirely a perception of the shooter. The AR is NOT like a stocked bolt gun, and reacts differently. Forcing fit and finish standards for a presentation grade gun don't apply. It's a battle rifle.
Be that as it may, some tinker with the fit so it won't be loose, using an foam ear plug to take up slack. That's like jamming a cigarette butt under the rear action and stock. On a 2MOA milspec gun, little changes, but the shooter feels good about it. In reality, the Army gives you dogtag silencers and does nothing for the looseness. It's a matter of which is more important as judged by experience in battle, not virtual reality.
It goes so far that some will buy any barrel and any bolt, assemble, and fire, without a headspace check. That is risky, but done. No one recommends it. No one would do that with any other action. The Army tells you it can kill you in the TM. But some still do it. For best operation and accuracy, any barrel should be headspaced to the bolt it will use. Nonetheless, you see barrels alone, with the receiver extension already pinned and "set," for sale everywhere.
As said, you can get any kind of fit to the lower that the industry tolerance stack will create, from literally hammering the pins in, to a sloppy fit that shows a lot of daylight. What most completely get wrong is that the fit will not affect accuracy whatsoever. It's entirely a perception of the shooter. The AR is NOT like a stocked bolt gun, and reacts differently. Forcing fit and finish standards for a presentation grade gun don't apply. It's a battle rifle.
Be that as it may, some tinker with the fit so it won't be loose, using an foam ear plug to take up slack. That's like jamming a cigarette butt under the rear action and stock. On a 2MOA milspec gun, little changes, but the shooter feels good about it. In reality, the Army gives you dogtag silencers and does nothing for the looseness. It's a matter of which is more important as judged by experience in battle, not virtual reality.
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