What is the practical difference between an A2 govt. and HBAR 20 inch AR barrel

[1911user]

I know the technical difference is a pound of metal shaved from the barrel under the handguards. Attaching an M203 grenade launcher is a non-issue

Can the HBAR be used with a tight sling (or bipod) without a shift in the POI? What about balance and handling? I'm trying to decide which to get and I'm not sure how much difference there is between the 2. This would be for a general purpose rifle. Barrel twist would be 1/9 or possibly 1/7 with an A2 govt. barrel.

 

[Raygun]

Well, I have a 20" Bushmaster HBAR (1/9") on mine. It's noticeably front-heavy compared to the government profile barrel, so it does make a little difference when swinging it around, as well as firing offhand. Not much IMO, but some.

I have an Olympic FIRSH rail on it, so a bipod doesn't really affect POI as the handguard is free-floating. My front sling loop is mounted to a GG&G flip-up front sight, but I haven't noticed any substantial difference in POI after shooting, walking a bit, and shooting more. At last nothing that couldn't be attributed to the barrel cooling down or something else. POI shift has been negligible. Not very scientific there, but that's what I know.

It's a good barrel. I have consistently gotten right around 1 MOA (at 106 yards, lased) with it and 55 grain Winchester Supreme Ballistic Silvertips in five-shot groups. So far 0.77" is the smallest group I've gotten, but 1-1.5" is more typical.

 

[1911user]

I've been doing some reading and am thinking that the A2 profile barrel and a free floating HG (without rails) might be a better combo than the HBAR with a standard HG. The weight would be about the same and there would be no worries about slings or bipods. The typical downside is added cost and perhaps complexity.

 

[jefnvk]

I've shot both, and yes, the Gov't feels a bit better, due to lack of forwrd weight. I would think, though, that any POI changes would be similiar.

 

[Raygun]

I don't have a 20" goverment-barreled rifle readily available to compare it to. Really, I don't think it would make a whole lot of difference unless you shot competition or did a whole lot of plinking in a short amount of time. Obviously, the HBAR is likely to be more harmonically stable and if you get the A2 barrel to heat up substantially, it stands to reason that with less rigidity in the middle of the barrel and more mass up front, the muzzle is likely to droop faster.

But you are saving a good amount of weight and an A2 barrel with a free-floating handguard should shoot minute-of-coyote without problems. Anyway, I guess my opinion on the matter is pretty clear.

 

[EShell]

Because the sling attachment point is (indirectly) to the front end of the barrel, any use of a M1907 style sling setup; i.e.: "Tight Sling" WILL influence your POI. The "HBAR" barrel 'should' be more rigid, thus resisting the side pressure a bit better, but both are definitely affected. Same for the bipod, but not as bad, since the bipod puts much less torque on the rifle (only the forward weight) than does a properly applied M1907 style sling (as much as you can stand). Anyone shooting competition, or varmint hunting, usually goes the free-float route.

I prefer the "government profile" for carrying and handling, but the HBAR does "hang" a lot better and would be easier for me to hold steady for long shots.

Accuracy, as usual, will be more a function of barrel and bore quality than profile.

There are free-float conversions out that look very much like a regular A-2 handguard setup, and there are also "float tubes" available, that allow the barrel to free float from the barrel nut forward. Both add a little front end weight compared to a standard A-2 handguard & hardware setup.

 

[hksw]

Why don't you just get one of the many CMP geared ARs that a few manufacturers build. most of them have a bull barrel under the handguard (turned down from the fronto sight forward to comply with the external dimensions) and between the handguard and abrrel is a free floating tube that the bayonet lug and front sling is attached to.

 

[Onslaught]

Athough my rifles are 14.5" - 16", I have had A1(superlight) A2, fluted HBAR, and full-on HBAR... In barrels of the same quality (i.e. rack grade chrome lined Bushmaster/RRA type barrels) I have never seen any difference in accuracy that could be attributed to the barrel diameter. I can tell you that my free-floated and fluted HBAR is more accurate now than it was when it was a RRA full .920 all the way to the FSB HBAR with standard handguards...

My vote is for the A2 profile barrel with a Clark's Custom or Hiperform carbon fiber float tube ($90 - $110). You can add a sling swivel to the float tube after it's mounted to remove any worry of "tight sling" or bipod issues. It will also end up being somewhere between the same weight as (Hiperform) to maybe even a couple ounces LIGHTER than (Clark's Custom) the standard handguard setup.

The weight would be about the same and there would be no worries about slings or bipods.

FWIW, an A2 profile barrel with free floated handguard (most brands) will STILL be lighter than an HBAR with standard handguards...

 

[Raygun]

 

[1911user]

Thanks for the good comments. In spite of logical thought, I found a colt HBAR upper (complete) for $330 and bought it (price was a factor). For now, I'll have an interesting rifle made from quality parts for $590. In 6 months it'll likely be in a different configuration, but everyone starts somewhere. Here's links to pictures of the upper and lower:

Lauer lower with Vltor CAR stock
A2 HBAR upper 1/7 colt

 

[Onslaught]

Don't sweat it... You bought an AR, and that's never a bad thing

The GOOD news is, if that barrel turns out to be too heavy for you, you can send it to ADCO (check out the "shop services" section" and have it reprofiled to A1, A2, mid-weight, or whatever you want for a mere $65!!!

That's what happened to my RRA HBAR (although I went with KKF who does great work but took 3 months!) it went from .920 under the handguards to .850 and fluted. It shaved off 8 ounces and made a big difference in the balance. If I were doing another one I would go with ADCO. They do great work and the turnaround is 1 to 2 WEEKS!