The more I shoot my 213, the more I actually prefer the 9mm to 7.62 when it comes to carrying it as a practical carry piece. I mean, 7.62 is literally a blast to shoot, but the flash and bang are a little much without ear protection.
I have been carrying the 213 on my hip the last couple of hikes. Cheap, built like a soviet tank, reliable, accurate, and very slim on the hip or in the vest pocket. FMJ 9mm should be more than enough for any critters I might stumble across (raccoons, dogs, etc) that could be hostile.
Still planning on converting a t-54 though.