Yeah, that seems like a weird thing. Why "fix" the muzzle device on like that? FWIW, I thought after about a gazillion iterations it was settled that an SBR was not a "rifle" and 922r was irrelevant. You become the manufacturer of the SBR therefore it is domestically manufactured using some foreign made parts, no? It gets confusing. Wish I could help. I swap out enough crap that I have no issue hitting the count so I haven't sweated it.