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Posted: 1/6/2005 11:08:48 AM EDT
[Last Edit: 1/6/2005 5:27:46 PM EDT by pathfinder74]
I'm trying to order a new flip-up front sight and gas block combo system (either the Les Baer, Young Mfg, or the PRI).

I need to know is if the diameter is either .750 or .938.

Is .750 the standard barrel diameter and .938 for a bull barrel/HBAR? Or Vice versa?

Or is .750 more of a standardized diameter and .938  is more rare or only used on a certain brand of rifle?

Bushmaster V-Match Carbine

Link Posted: 1/6/2005 11:23:57 AM EDT
Assuming (dangerous, I know, possibly making an ASS-U-ME), that your Bushie has the factory VMatch barrel, I'd say the diameter is .750". I have a factory 20" VMatch rifle that I just measured to confirm and it is .750". Also, you can always call Bushie if in doubt.

HTH.
Link Posted: 1/6/2005 4:54:10 PM EDT

Originally Posted By Clay:
Assuming (dangerous, I know, possibly making an ASS-U-ME), that your Bushie has the factory VMatch barrel, I'd say the diameter is .750". I have a factory 20" VMatch rifle that I just measured to confirm and it is .750". Also, you can always call Bushie if in doubt.

HTH.



I doubt the 16" carbine has a different diameter than the 20". The V match series are all HBAR if I'm not mistaken, so it should be the same across the board.

I'll wait for a couple more posts of a similar response before I make the order. If nothing else, it's a test of people's knowledge...
Link Posted: 1/6/2005 5:32:17 PM EDT
Link Posted: 1/6/2005 5:40:59 PM EDT

Originally Posted By Troy:
Virtually all modern AR barrels are .750" at the FSB (this includes both "government profile" [20" A2, M4, etc.] and HBAR barrels).

The .938" FSB are for "bull" barrels, which are super-heavy, usually .980 for most of their length.

-Troy



So an HBAR and a bull barrel are not the same? humf... thought they were. Bull barrels: are they generally the really thivk diameter ones that are usually stainless?

Thanks Troy.
Link Posted: 1/7/2005 7:07:02 AM EDT
[Last Edit: 1/7/2005 7:09:44 AM EDT by wyv3rn]
Got Get a caliper.?  It's a good buy.  You think you only need it to measure one thing, but you'll start measuring everything you can think of/was ever curious about.
Link Posted: 1/7/2005 7:30:28 AM EDT
[Last Edit: 1/7/2005 7:31:00 AM EDT by mongo001]

Originally Posted By pathfinder74:
[So an HBAR and a bull barrel are not the same? humf... thought they were. Bull barrels: are they generally the really thivk diameter ones that are usually stainless?

Thanks Troy.



Yes, bull barrels are generally very thick thoughout the whole length and are generally stainless.

That V-Match rifle will have a 0.750" gas block area.
Link Posted: 1/7/2005 11:30:54 AM EDT

Originally Posted By pathfinder74:

Originally Posted By Troy:
Virtually all modern AR barrels are .750" at the FSB (this includes both "government profile" [20" A2, M4, etc.] and HBAR barrels).

The .938" FSB are for "bull" barrels, which are super-heavy, usually .980 for most of their length.

-Troy



So an HBAR and a bull barrel are not the same? .



Correct they are not the same.

HBARS are heavy under the handguards and step down to .750-.720 for the Front sight forward.

Bull Barrles are generally 1" (.98 qualifies) or so from chamber to muzzle.  As far as I know DPMS is the only major AR Mfg that sells Bull Barrels in their standard product line.
Link Posted: 1/8/2005 11:07:12 PM EDT
Most large auto parts stores carry calipers now, even the cheap ones will work fairly well if you are gentle with them.  I've seen them for $15-20 locally.   Don't assume anything, I've seen bull barrels that are .938, .980, 1.00" etc. etc.  It seems different manufacturers turn them to different diameters.  If you have a stack of different manufacturers catalogs, you will see all kinds of different gas blocks and FSB's for varying diameter barrels.  A standard "HBAR" or Mil-spec barrel is supposed to be .750 at the FSB/gas block, but now it seems like everyone is doing something a little different in order to grab a piece of the market.  "measure twice, install once".
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