SIG Sauer Rifles
Had a couple questions regarding the MPX foregrip:
1. Is it legal to attach a foregrip to the MPX or do I need get ATF stamp? I plan to SBR it but in the meantime, was curious if I can legally do this.
2. Ordered a foregrip off eBAy that should fit the Picatinny 1913 rail and the foregrip was...