before savage got into building short actions they would put short action calibers in a long action body and usually put a block of some sort in the back of the magazine. there is probably a collar on the bolt as well. a few years ago savage started to make short action recievers. i have a model 10 in 243 and a model 12 in 22-250. both of which are short action rifles. a friend of mine has a 110 in 243 and it is a pretty good shooter, but there is a noticeable difference in its groups vs. mine. the only thing i can come up with is that my short action is stiffer and doesnt "flex" as much as his long action.