I was just looking at one of my barrels and noticed something. On the top front it reads: B MP 5.56 NATO 1/7. For some reason I'd figured most if not all BM barrels were 1/9. In the catalog, BM only offers 1/9 on the M4 barrels.
Is this a common thing, or do I have a more unique barrel?
It was bought as a Bushmaster barrel, and I'm pretty sure it is one.