I recently acquired a Remington 700 bdl in 7mm rem mag. The gun seems to have a very tight chamber but it will cycle factory loads in lighter grains (sometimes still a little stiff). I was given a lee loader Hornady brass and Hornady 175 grain (core lock?) and after making my first round it gets pulled out of the magazine fine but it jams the gun and stuck in the barrel. After removing it I made a dummy round to see what's going on (no powder or primer) and it did the same thing, this one actually collapsed a little behind behind the neck. Everything measures out ok, what am not doing? Thanks for all the help! I forgot to mention that the brass cycles fine before the bullet is inserted, and the bullet diameter is correct.