I'm finishing up my "general purpose" carbine project.  It's a pre-ban, flat-top Bushmaster with a RRA mid-length barrel.  I will be free floating it with either a YHM lightweight or Daniel Defense forearm.  I will TRY to get a TA01NSN for it, and if not, I'll get an IOR M2.  It will have a fixed FSB and a KAC 200 - 600 meter BUIS.

I have 2 brand new barrels, one of which will be going on this rifle, the other will go on the EE to help fund the optic.  Both started life as a RRA chrome lined mid-length HBAR.  One has been turned to A2 profile by ADCO, the other was turned to about .850" and fluted by KKF.  There is some difference in weight, but I don't have a scale to see how much.  But it is noticeable.  (A2 is lighter of course)  Both are noticeably lighter than the original HBAR profile by a much larger margin than the difference between the two profiled bbls now.

Rifle will be used mostly for range time.  It might be carried a little (200 - 500 yards one way using a CQB Solutions sling), but NEVER any real "humping".  Occasionally, there will be shots taken at the range out to 500 yards, with most being between 200 - 360 yards.  There is a good possibility of some armadillo and coyote dispatching with this rifle.  

It doesn't need to be match accurate, but I'd like accuracy to hold together during a 2 hour range session firing 100 - 200 rounds.  (no mag dumps, usually 3 - 5 shots, then check targets, adjust elevation, whatever).

My question:

Of the two barrels mentioned above, which barrel would serve me better on this GP carbine?  

Is there REALLY any advantage to the heavier fluted barrel in the long term accuracy department?  Or is the lighter weight barrel going to be just as accurate?  
(any first hand range experience with ADCO's A2 middies welcome)

"BOTH" is not an option.  I have a 6.8Rem SPC on my short list for "next" and maybe an SPR-ish rifle for the longer term.  I have no use for (and cannot afford) 2 similar carbine setups.

I'm not new to the fluted barrel, but this is my first A2 profile.  I know which way I'm leaning, but I'd like to hear other educated opinions on these choices before I make the permanent decision.

Thanks for the input

"Rifle will be used mostly for range time. It might be carried a little (200 - 500 yards one way using a CQB Solutions sling), but NEVER any real "humping". Occasionally, there will be shots taken at the range out to 500 yards, with most being between 200 - 360 yards. There is a good possibility of some armadillo and coyote dispatching with this rifle.

It doesn't need to be match accurate, but I'd like accuracy to hold together during a 2 hour range session firing 100 - 200 rounds. (no mag dumps, usually 3 - 5 shots, then check targets, adjust elevation, whatever)."





An M4 profile barrel would be fine for your intended use, although the added heft of a .73-.74in straight tapered barrel (.75 at gas block) might help with stability for those long shots you are talking about.  My personal preference is that the M4 barrel is too light for easy accurate work, the weapon has a light BB-gun feel to me and won't sit still from a bench or bi-pod, but that might just be me.

My longer range M4 weighs about 10-11lbs with optics, light and bipod and it sits rock solid on a bench, or bi-pod in the field.   I carry it all day still hunting deer and it doesn't get very annoying, so that weight should be well within your 200-500yd slinged carry comfort zone.

Thanks for the quick response...

Just a note - The ONLY 2 barrel choices I have are mid-length turned & fluted under HG or mid-length A2 profile.

It's not too hard though to apply your answer to the 2 available barrels.  M4 = A2 etc.

Any more input?  I'd really like to hear from someone with time behind one of the ADCO A2 Middie barrels.

Thanks again

For a "general purpose" carbine I'd pick the A2 barrel because it's lighter.  I don't have any experience with the Adco A2, but I just had a RRA stainless mid-length turned down to approximately A2 profile.  I haven't had it back long enough to really try it out, but from the groups it was shooting when I re-zeroed it, it seems to shoot just as well as it did as an HBAR.

BTW, have you considered one of the BAC ACOGs instead of the NSN?

Thanks Mike... that's the way I was leaning anyway.

BTW, have you considered one of the BAC ACOGs instead of the NSN?

Yeah, I have, but a quick test at 25 yards showed me that I'm not one of those guys who can use the BAC.  First, my eye doctor tells me I'm right eye dominant, but I'm left handed and have been shooting this way for 25 years with no plans to swap.  It works for me.  I vaguely remember Dad making me switch eyes as a little kid.  So the reticle kinda disappears sometimes when I'm trying to use it.  Also, from a still position, looking through the optic and trying to concentrate on the BAC concept, there's at least 6" - 8" difference between the two points of aim.  Maybe that's normal, but I don't know.

Plus, the NSN is $300 cheaper than the TA31, which is enough difference that I could get a Doctor Optic for the ACOG's rear sight and use it instead of the BAC reticle.

The jury's still out though... I may only be able to afford an IOR.  (you'll probably see a thread on that soon )