CptCurl,

I more or less agree with SP2 and a possible headspace problem. I'm afraid the 9.3 x 74 having any useful shoulder to help headspace is pretty dismal however. Even if the die is set back sizing I usually have the firing pin strike able to drive this gentle tapered brass deeper re-creating the problem. If it doesn't help that is probably what's happening.

Rim thickness....... This is critical and sometime in the past I remember someone saying the RWS rim was thicker than the Norma by a few thousandths in 9.3 x 74. That would help if still true.

If the gun were mine CptCurl, I would do the following. I would punch out several round discs about 1/2" diameter out of your computer paper. (20# paper is usually about .004" thick) Take a couple of empty cases (unprimed) and Lightly dab a slight amount of weak glue (like paper glue) to a disc of paper and stick it to the back of the empty case. Let it dry and then try it for closing in your double one barrel at a time. Feel for slight resistance just before lockup without using any force; all you want is the excess space measurment.(headspace) If they do easily close, then glue two thicknesses on and try again. If two go, then try three, if three or more discs will easily close glued to the back of a case then the gun could be causing the early case separations........Paper thickness can be varied as well if the exact headspace is of interest............

BigRx