Building a 20in upper

More
7 years 1 week ago #47985 by Goldsmith
Building a 20in upper was created by Goldsmith
Hey everyone I'm building an upper with a 20 inch barrel. For the sake of getting my project up and running I bought a 20 inch AR Stoner barrel. It was cheap but got good reviews and I figured I could at least try it out and buy a better barrel later if I need to. The barrel was only $100. Anyway a couple of the reviews rated the barrel well but the reviewers said that they needed an AR10 rifle length gas tube versus a lr308 rifle length gas tube. I guess the AR 10 rifle length is a1/4 inch longer than the DPMS lr308 rifle length and the rifle will short stroke without the longer tube. What I found strange when I put everything together was how much further the gas tube comes into the receiver than my carbine length gas tube on my other upper. The bolt still closes all the way so I don't think the gas tube is making contact with the bolt but can my gas tube still be to long and will that cause me any problems. Any info help, thanks!

Please Log in or Create an account to join the conversation.

More
7 years 1 week ago #47986 by jtallen83
Replied by jtallen83 on topic Building a 20in upper
If it doesn't bottom out then you should be OK, post a picture of the end of the tube in the receiver and I should be able to say for sure, at least as sure as things can be with these 308AR builds. I recently did a Fulton build that had the tube running well past the halfway point of the cutout in the receiver, rifle runs great.

Please Log in or Create an account to join the conversation.

More
7 years 1 week ago #47988 by Goldsmith
Replied by Goldsmith on topic Building a 20in upper
Hi! Thanks for the reply, here's the pic.
This image is hidden for guests.
Please log in or register to see it.

Please Log in or Create an account to join the conversation.

More
7 years 1 week ago #47989 by Goldsmith
Replied by Goldsmith on topic Building a 20in upper
Here's the pic, looks like mine runs just a bit past the 1/2 way on the cutout too.

Please Log in or Create an account to join the conversation.

More
7 years 1 week ago #47990 by jtallen83
Replied by jtallen83 on topic Building a 20in upper
That should be fine. It may give a bit longer gas impulse but that will actually help reliability. Worse case you are a bit over-gassed, that can be fixed with an adjustable gas block or a heavier buffer if it should cause function issues. Odds are you will not see any issue from this though.

Please Log in or Create an account to join the conversation.

More
7 years 1 week ago #47991 by Goldsmith
Replied by Goldsmith on topic Building a 20in upper
Thanks for the input, I'm looking forward to taking it out soon, I'll make sure to post how it does. Thanks again!

Please Log in or Create an account to join the conversation.