Questions on AR-15 carbine options

[Telperion]

Due to recent developments, I may have the opportunity to build an AR sooner than I thought. I have a pair of questions:

1) Barrel length: 14.5" vs. 16". I'd like something as short as possible without the Title II hassle. Apart from the velocity drop, what are the disadvantages of a 14.5" barrel (w/ pinned flash suppressor) over the 16"? From a maintainance standpoint (cleaning the gas system, I imagine), how much of a difficulty is it to have a permanently attached flash suppressor?

2) Mid-length carbines. If 16" ends up being my choice, I'm considering a mid-length gas system. Compared to the easily-available complete carbine uppers, how available and expensive are mid-length uppers? Is there a mid-length Larue float tube available?

 

[Bartholomew Roberts]

1) Barrel length: 14.5" vs. 16". I'd like something as short as possible without the Title II hassle. Apart from the velocity drop, what are the disadvantages of a 14.5" barrel (w/ pinned flash suppressor) over the 16"? From a maintainance standpoint (cleaning the gas system, I imagine), how much of a difficulty is it to have a permanently attached flash suppressor?

There is really no need to clean the gas system; but if you ever need to replace a front sight base; mount a new rail, etc. then the pinned suppressor is a pain because you have to have it cut off and reattached.

2) Mid-length carbines. If 16" ends up being my choice, I'm considering a mid-length gas system. Compared to the easily-available complete carbine uppers, how available and expensive are mid-length uppers? Is there a mid-length Larue float tube available?

There are many different people offering midlengths these days - RRA, Armalite, Sabre Defence, CMMG, and several other guys who do more custom work. Almost everybody makes a freefloat midlength tube as well (anything marked 9.0 will be just perfect for a midlength), including Larue.

 

[jungle]

Unless you want to go through the hassle of SBR paperwork the 14.5" will give you less velocity for the same length weapon. The addition of the permanently fixed muzzle device will limit your options if you want to change or modify your handguards or flash hider later.
Midlengths give you a little more sight radius which is good for irons.

 

[Telperion]

Thanks. I'm leaning toward the mid-length. I want the ability to service my rifles without sending it to smith to cut the FS off, and I never liked the looks of the 16" M4 barrels -- too long for the length of the handguards, I think. The mid-length looks better proportioned and I like that they are not as hard on the internals as carbine gas systems.

 

[Master Blaster]

Mid length.

and best of all you can use a bayonette with a midlength upper, at least you can if its a Rock River arms.

 

[ctdonath]

Been mulling this over. My humble take:
20" gives enough range that I might as well use a .308 instead; too long for close-quarters social use.
16" ideal if SBR is too much hassle.
14.5" not enough improvement in compactness to warrant SBR paperwork and velocity loss; longer flash hider to avoid SBR is better used by 1.5" more barrel.
11.5" distinctly shorter range, but significant improvement in compactness helps close-quarters social use, especially by allowing enough space for suppressor.
10.5" or shorter suffers too much velocity & reliability loss.

Go with 16" for general-use AR and 11.5" for close (under 70m) use.

Having escaped NY to GA, looks like I'll get an 11.5" AR soon; applications needing longer barrel are better suited by a 19" .308 w/scope.

 

[rangerruck]

the shorter legnth bbl is harder on the parts of the whole system not just the gas block. you may want to skip that and get a krebs custom or robinson armament, better than the typical ar uses ong, or short stroke piston like an ak. very clean longer lasting.