Welcome kam,

I'm not sure what you're asking about? The 12's are all short action, the long action version would be a 112. The best way to tell is to measure the distance between the action screws. There's nothing stopping someone from screwing a short action barrel onto a long action receiver. Are you calling it a "12" because that's what is stamped on the barrel? If it's 5" between action screws, it's a long action. If it's either 4.25" or 4.40" between screws, then it's a short action.

I have a 22-250 (it's the one in my signature) for prairie dogs also. I'm running the 50 gr vmax over 40.0 grs of H-380 at just over 3800 fps. I get one hole groups @ 100 yds from a solid rest. I also love those 250 count boxes. Good splat factor also.