I need barrel length advice!

[PackerfanXD]

I'm filling out my paperwork and I need to figure out what barrel length I'm going to go with.
I wanted a 7.5" because I figured that if I was going to go short I might as well go real short but I'm worried a bit about reliable cycling.
Thanks for your thoughts on the subject.

[rogerxd45]

ive thought the same thing

i personally would go with at least 10" it will still be noticable shorter then a regular one and will provide at least some increase of reliability and improved parts wear over a 7.5

but going with anything shorter then a rifle system will be less reliable (even the carbine length is supposedly less reliable but i cant say first hand) and will increase wear. but with the right setup they can be tuned to work quite well but i dont know if their is much that can be done for parts wear but thenagain i havent looked into it too much

check into a piston set up, that might be something that could help but once again i dont have any first hand expiernce with short gas systems so all of my advice is all second hand. All i have is a rifle length system

[Polymerhead]

I would do some looking around the net and get a good idea of what you want to build/buy. I did the 7.5" because I wanted a very short AR. The threads on a 7.5" barrel start just before the end of a carbine rail, looks pretty good with a flash hider.

No reliability issues, by the way, but I had it built. I think if I built an upper this short I would expect to tweak it some before it ran 100%.

[PackerfanXD]

I won't be building the upper...

[PackerfanXD]

I guess what I need to know first is; on my paperwork they want to know barrel length. Can I say 7.5" now on the paperwork and later change my mind and buy a 10.5" when my tax stamp arrives?

[Polymerhead]

Originally Posted by PackerfanXD

I guess what I need to know first is; on my paperwork they want to know barrel length. Can I say 7.5" now on the paperwork and later change my mind and buy a 10.5" when my tax stamp arrives?

Yes, just send a letter certified mail stating that you'd like your records changed. Same process as if you're moving. They'll write back saying they've changed it. If you want to be super-safe you might want to wait until you get the confirmation back to re-build it, but I don't think anyone's going to bust down your door and measure your barrel. Sort of the same issue as if you have 2 uppers for your lower. Common opinion is that unless you permanently change configuration (say, switch out the 7.5" barrel with an 11" one then sell the 7.5" off), you don't really need to write the BATFE and let them know.

[PackerfanXD]

I am just going to write "minimum" where they ask the length.

[rogerxd45]

Originally Posted by PackerfanXD

I am just going to write "minimum" where they ask the length.

i would go talk to a class III dealer before you write "minimum" just because it would really suck to get rejected just because you didnt fill it out correctly. when i bought my shotgun they did all the paper work and i just filled in a few personal information boxes. they were very helpful in walking me through it. but i would definitely have a class III dealer double check EVERYTHING before you send it off

a 7.5 upper would be really cool i would just worry about parts and such but i dont have first hand experience

[PackerfanXD]

Edited.