AR gas block inside diameter help

[Chrs2fer23]

Hello all......I am looking to replace the gas block on my Bushmaster XM15-E2S HBAR. I was looking in a catalog and the gas blocks come in three inside diameters....0.625, 0.750, and 0.936. I have no clue and I don't have anything to measure in such small increments.

Anyone know what this Bushmaster may have or can clue me in to help figure out which size I need??

Thanks for any help......

 

[balloo93]

If you have a harbor freight near by, they sell a micrometer that would measure it. Otherwise, I'd say call BM and ask them.

 

[Chrs2fer23]

I actually found a little cheap-ass micrometer in my toolbox....my barrel is exactly three-quarters of an inch(0.750), so I think I just figured it out......thanks for the suggestion balloo93.

 

[Angered_Kabar]

My guess would be 0.750 inch.

Measure the diameter of the barrel underneath the front sight base as best as you can.

0.625 is usually used for light weight barrels or on the M16A1. My bet is it's not that size. 0.936 is used on bull barrels, but yours is a heavy barrel. 0.750 is the most common size.

 

[Chrs2fer23]

Thanks Angered_Kabar, I believe you are correct......