What length for first SBR?

Also, once you have the lower and form 4 done, you can have multiple uppers and calibers. Just make sure you can return it to what the form reads at all times. I want to build a 8" 300blk, 5" 9mm and a 7.5 Pdw all on the same lower.

I would also recommend the LLC or Trust route. And the last 4 forms took 6months +/- a week. Shoot me a PM if you have any questions.

7.5" is not very forgiving. You have a very short gas tube and no real barrel to give you any dwell time after the gas block. You end up with high pressures over short distances and short periods of time, which is hard on the gun.

My first go-round with this gun was a Noveske barrel, Vltor receiver and low profile gas block, an LMT enhanced BCG, and a Vltor receiver with H3 buffer. It ran like crap. First it was short stroking. Tried swapping buffers, but that wasn't it. Plenty of high pressure, but it was bleeding off before the bolt fully unlocked. Had to swap out to a non-enhanced carrier (without the extra hole) to stop bleeding off the gas. Then I had bolt bounce. H3 was too heavy, H was too light. Had to go with an H2 to get it to run reliably on cheap 55gr XM193.

I know a bit about ARs, and I have friends who know a lot more about them then I do. I also worked in a gun shop and range with a ton of parts to swap in and out, so none of this was insurmountable. They also wisely kept me from just drilling the gas port. The point of all this is that the shorter you get, the more of a crapshoot things are. Maybe everything works out just fine. Or maybe you end up constantly adjusting a thousand things at some expense until you get frustrated or broke.

If this is your first SBR, and you are going to build it yourself, I'd highly recommend sticking with a more common length. 10.3 is fine, 11.5 is better, 12.5 is the most forgiving.

And to shill for the man I was impressed with locally, Bert of BPTactical does a hell of a job cutting and properly threading barrels.

I don't know Colorado geography very well as a newcomer, but if you are ever up in the Greeley/Windsor/Ft Collins area and you give me enough notice, I can probably let you try a couple different ARs with short barrels and you can get a feel for it yourself.

The super obscure 9.5":

http://www.johnnyego.com/firearms/ar...s2/ubrvisc.jpg

I did a 14.5 first the went to a 10.5 with AA piston system. I might do a 12 or 12.5 OR go back to a 14" with AA piston, decisions, decisions.
The 7" dedicated 22lr and 10" 9mm enjoy their time on the range too.

FWIW - The 7in (carbine) gas system was originally for the Colt Commando during Vietnam. What Colt (and the military) found during field testing was that the 11.5in barrel was more reliable than the 10in barrel it was originally issued with. That's the length Colt Commandos are built with today.

Can you get a shorter barrel to run? Hell yeah! My first SBR was/is a 10.5in that has 25K rounds through it and still runs fine. One of my work guns in an 8in. However, as other people have mentioned, they will require more tuning and more parts maintenance (the shorter you go the more the gun will beat up its parts when it cycles).

My advice for a first SBR would be 11.5 in. It's short enough to be handy and is easy to make run. Buy one from a quality manufacturer (LMT, BCM, Etc) and you should just be able to plug and play.

As far as muzzle devices go, I don't believe the 5.56 round in any configuration has enough "umph" to make one necessary. If you try one and decide you like it, cool. But I don't think you need to "plan" on dropping an additional $100+ on a muzzle device to make the gun shootable.

My 7.5" did take some tuning but shoots like a champ now. I did the 7.5" first because I wanted a fun gun. It is actually more accurate than you might think with the 7.5" Noveske Diplomat barrel.

My next will be a 10.5" so I can get a can.

http://i1222.photobucket.com/albums/...i/IMG_2154.jpg

http://i1222.photobucket.com/albums/...i/IMG_2152.jpg

I see "barely used" 10.5" lmt uppers for sale pretty often. I got mine with a sure-fire quad rail and bcg for right at $500 of gunbroker. I love it.... and im my opinion a 10.5 is just as "cool" as a 7".

I added a battle comp 1.0, and it runs great..... a lot less snappy than the A2.

I started with a 10.5" LMT upper and regret selling it a few months ago, -the thing refused to fail, no matter the buffer/ammo/suppressor, it just never had a single hiccup no matter how hard I tried to make it cough.

I now have a BCM 11.5 upper which runs just as well. I only replaced the LMT upper to reduce wear/tear on my suppressor. If a suppressor isn't in the picture, an LMT 10.5 is a pretty good value and has been mentioned above, finding them used on various for-sale boards is fairly common.

When I switched from the 10.5 to the 11.5 upper, I sent a letter to ATF and laminated a photocopy of their return acknowledgement of the length switch that I keep in my range bag.