with my chamber length gage (sinclair) touching the lands is 3.790. Ok .050 off the lands for the barnes 180tsx is 3.740 my magazine will only hold 3.615 thats a jump of .175 this is on a pre64 model 70 rechambered from 300 H-H. The gun shoots 165gr sst jumping that much great 1/2 to 3/4 all the time but going elk hunting next year and want to use the barnes tsx. my question, Is the throat going away or does this sound like normal for my pre64?

just make them so that they fit in the magazine

quote:

my question, Is the throat going away or does this sound like normal for my pre64?

I would ask the gunsmith that cut the chamber for the throat length on his reamer. Unless you have a bunch of rounds through the barrel I would say chances are that you have the longer throat specs from factory rifles. IIRC my gunsmith told me that some of the factory Ultras have throats in the .200-.300 ballpark and maybe longer.

My 375 Ultra has a .085 throat and allows me to load to 3.65 which is perfect. Having said that I would load them to fit the mag and you should be fine.