5/8-24
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That is nuts. For what it's worth Bergara makes nice barrels. We've run two of them with good results.
The both shot 1/2 MOA with 77 gr SMKs. They're both still in the shooting rotation, but are less than 2 years old. Both are Stainless, but one came with the black finish. I forget what they use, but the black barrel took a little longer to settle in and shoot 1/2 MOA. The plain SS barrel shoot great right out of the gas. Both are gassed good.... i.e. the ports aren't oversized.
Here's the thread I started when we first put them together.
https://www.m4carbine.net/showthread...a-Barrels-Boys
IIRC, Stainless is only accurate because the rifling is formed (cut/button/whatever) to the exact specifications of what it should be, while any barrel that will be chrome lined has to be made slightly larger to take the lining into account, which causes some accuracy degridation. There's no reason a carbon steel barrel without chrome lining can't also be just as accurate.
[QUOTE=markm;1929787]The both shot 1/2 MOA with 77 gr SMKs. They're both still in the shooting rotation, but are less than 2 years old. Both are Stainless, but one came with the black finish. I forget what they use, but the black barrel took a little longer to settle in and shoot 1/2 MOA. The plain SS barrel shoot great right out of the gas. Both are gassed good.... i.e. the ports aren't oversized.
Damn it seems that bergara dropped a ton of barrels off their production line
Here's what they say about the 5/8-24 thread:
NOTICE*** THIS BARREL HAS 5/8-24 threads to keep the bore at the muzzle from swelling like most barrels threaded 1/2-28. The tighter bore at the crown gives better accuracy.
Anyone hear of 1/2-28 threaded muzzles swelling? Also might not be ideal if you are the type that changes muzzle devices more often than you change your underwear.
I've heard this from our riflesmith. When he threads a bolt gun, the does something to minimize this issue.
It's also true of these sporter hunting guns where they turn the barrels down too light. The bore diameter increases. Apparently when the barrel button is pulled through the barrel tremendous stresses are put into the steel. Then if you come along and remove a bunch of the external barrel steel, the bore will actually open up some.
(forgive me barrel manuf gurus if I'm hacking this explanation to bits)