I have the 300 BLK in an AR, and the only word that comes to mind is FUN!!! Is it really practical, no. Is it more fun than the 416 Rigby? Heck yes. The kids and grandkids love the BLK. Ammo is reasonable, now that you can find it. If you reload, 223 brass is laying everywhere to make the BLK from. That it isn't the best choice for deer isn't really an issue with me. There are better choices for that. If you have the coin and desire, the BLK suppressed fills a need that most of us just don't have. I have the big magnums in droves, like the 375 H&H, 416 Rigby, 405 Win, 45-70 (Not a magnum, but with my handloads?) and a 375 Black Mesa Express. That's what makes this hobby fun, choices. If it was all about suitability, a 22 single shot, a 12 ga pump, and a 30 cal anything over 30-30 would be all anyone would ever be able to justify.