GM barrel question

[hoz53]

hi everybody. I just received a 5.56 GM barrel blank. It is one of their gunsmith specials they sell for 50.00 or so. After cleaning it and borescoping I see the grooves look very shallow. I have not been able to check the bore size with a pin gauge. I don't have this size but will soon. Anyway I am just wondering if anyone else has noticed the grooves are shallow on these barrels? I don't have much experience at this or a way to measure them, so I may be completely wrong. Thanks. Hoz

 

[msalm]

They are closer to a .220/.224 bore groove barrel. They still shoot well. I've used a few of their 12 twist and lapped them before chambering/contouring and they performed solid 1/2 MOA on the AR platform for varminters.

 

[RWO]

I just checked a S&W M&P-15 barrel. It had a .220 bore. I did not measure the groove dia.

RWO

 

[hoz53]

I just checked a S&W M&P-15 barrel. It had a .220 bore. I did not measure the groove dia.

RWO

Thanks msalm. That's what I was wondering. So at .220/.224 that means a groove would be .002 deep right?

Thanks RWO. That gives me more of an idea about he depth of the grooves on these rifles.

 

[msalm]

Yep, .002" groove depth. Some barrels are ..219 so only have .0025" groove depth...as long as they're made decent they shoot either way.

 

[hoz53]

Yep, .002" groove depth. Some barrels are ..219 so only have .0025" groove depth...as long as they're made decent they shoot either way.

thanks again for the good info