You can run into that problem with a chamber that does not match your dies as one or the other is out of spec..Its no big deal just back off the die a bit at a time until you get a crush fit, and then I back off a very small bit more for functions sake, at least for hunting loads..
Don't over look the fact that perhaps your load is too hot for your particular rifle..
Don,
I have seen several 7x57 that 48 grs. of H414 was a too hot with some bullets or that weight. My 7x57 Brnos with long magazines and very long throats will take 53 grs. of same, but in effect the long magazine and throat are the same as Improving the chamber as I seat the bullet out and have considerably more powder space and I get a heck of a lot more velocity with those modifications..All my custom 7x57 are set up the same as the Brno 21 and 22...
