chopping a 16 inch carbine down?

[Trigger]

I did a little research on this and didnt find any threads relevant to my question, so my apologies in advance if this has been asked before.

I had an idea about picking up a 16" upper (or longer) with a carbine gas system (Piston wouldnt suck either though) and chopping it down to 10". now I understand that doing this will require an NFA which is current sitting around the fed office somewhere waiting on approval. but my largest curiosity is will cutting the barrel down affect the operation of the weapon itself? will it still cycle properly? and if not what can be done to remedy the problem. would it be smarter to just buy a 10" upper and be done with it? Just would like to see if anyone has any insight on this project I have in mind, any help would be appreciated!!

[BPTactical]

You may end up having to enlarge the gas port. When you shorten a barrel you create a gas impulse that is shorter in "dwell time" and can short stroke on you.

[Trigger]

I kinda figured it would be something to that effect, thanks!

[Great-Kazoo]

PM sent

[Maxpowers]

If you get a professional to do it, you'll be fine. I got 16 cut down to 14.5 and had a comp pinned and welded to it by tj's. Its been great. If you go that short though you will certainly need to adjust the gas block to fix the dwell time as stated above. Alot of people reccomend not going shorter then 11.5 because there is a 40 percent increase in dwell time over a 10.5. Your AR will be more reliable if you do that.

[hatidua]

I'm not sure how things are in the past week, but there are typically quite a few reasonably priced 10.5" LMT uppers on arfcom and various other classified boards.

[AKA-Spook]

A 10 -11 inch needs the port/gasblock in the pistol position.

[Great-Kazoo]

A 10 -11 inch needs the port/gasblock in the pistol position.

My 10 & 11.5" uppers all have the same position gas block as my spouses 16" ar's

[GunsRBadMMMMKay]

My current upper is a 10.5" with the permanent 5.5" brake (which is nothing more then counter-bored h-bar drilled full of holes lol), and carbine position gas port. Works just fine.


(am I performing thread necromancy here? I can stop, just bored.....)

[cofi]

Why would you want a 10.5 with a 5" brake?