Re: Flattened Primers
Chamber (real headspace) is pretty much irrelivant to a good hand loader, we make our sized cases fit our chamber.
What you have is excess case headspace for your ammo, meaning you're setting the shoulders back much too far, allowing primers to back way out and then get flattened as the case head flows back to the bolt face. That excessive case stretching will soon cause you a head seperation if you don't correct it.
A turn of a die changes its position right at .072". Back your sizer up maybe a half turn (31 thou) and size a case, then see if it will chamber smoothly; probably won't. Turn the die down about 16th turn (4 1/2 thou) and try again, keep repeating that until you can close the bolt with just a touch of drag on the empty case. Size the rest of your cases and try your loads again, the primers will proably be fine.