Question on AR-15 HBAR's

[Slater]

Though it's not a particularly popular configuration, several manufacturers (Bushmaster, Spike's, Stag Arms, etc) manufacture HBAR (heavy barrel) profile rifles. Is there a common/standard diameter for this type of profile or does it vary by manufacturer?

 

[Coal Dragger]

Varies.

 

[shootstraight57]

I had a Colt HBAR and later built another AR. I ordered a heavy barrel front BCA and the diameter was different.

 

[CapnMac]

Varies.
Also varies based on "when," too. The original Colt HBAR (if I'm remembering rightly) was only "heavy" to the front sight base (or perhaps the other way around). That was about the time the grenade launcher inset started appearing. If memory serves, there were some makers who had "full length" heavy barrels, which necessitated using the then-new free-float forearms.

The AR has had more than a few variations across its half-century plus span..

 

[Varminterror]

Hbar profiles are typically either straight 1.0” behind the gas block, or stepped down to 0.920-0.936”. Then use a 0.750” gas block, with straight 0.750” out to the muzzle. “Heavy barrels” are typically whatever the maker wants them to be, as are “bull barrel” or “semi-bull” contours. National Match contours are often similar to HBar, dependent upon the makers. Hbar and National Match profiles aren’t as popular because they’re heavy, but some of us love that extra weight. They’re also less laborious to machine, since the barrel isn’t turned in as many sections or as thin as other contours.

I use Hbar’s or Nat’l Match profiles on almost all of my personal rifles, except for the light weight go-fast guns.

 

[1911 guy]

Yep. Varies. I have one from Shaw that measures .750" from flash hider to barrel nut.