Most of us who've reloaded notice when cases "size" hard compared to others. In the way of 9mm P, I've discovered there are a few that size harder and seat a bullet tighter. One is CBC. Another is Fiocchi, marked GFL. But not all of them. The newer ones (poss. made in the US rather than in Europe) size hard and take a seated bullet with a lot of friction. A visual difference is, the ones marked G.F.L. with periods after the letters are fairly "normal," while the ones marked GFL with no periods after the letters are tough monkeys.
There are reasons why some brass cases response differently. I assume some are thicker than others, and the metallic composition might vary a bit. My thinking is that a bullet that seats extremely tightly might contribute to higher pressures. Because it would take a stronger impulse to dislodge it.
When I attempted to seat jacketed Hornady 135 gr. bullets in the newer Fiocchi cases, it was very difficult. I decided to try a different bullet. They didn't like 130 gr. plated bullets either. They would take a 115 gr. WW FMJ bullet with "normal" friction. I didn't cross section one of the cases, but there may be an internal case wall taper issue that I'm unaware of.
So I sorted the GFL cases into two piles based on headstamp markings, one for 115 gr. bullets and the others for 135 gr.
I've been working through the 9mm cases on hand, which were separated by brand. The 135 gr. bullets presented no issues with all other brands of cases.
There are reasons why some brass cases response differently. I assume some are thicker than others, and the metallic composition might vary a bit. My thinking is that a bullet that seats extremely tightly might contribute to higher pressures. Because it would take a stronger impulse to dislodge it.
When I attempted to seat jacketed Hornady 135 gr. bullets in the newer Fiocchi cases, it was very difficult. I decided to try a different bullet. They didn't like 130 gr. plated bullets either. They would take a 115 gr. WW FMJ bullet with "normal" friction. I didn't cross section one of the cases, but there may be an internal case wall taper issue that I'm unaware of.
So I sorted the GFL cases into two piles based on headstamp markings, one for 115 gr. bullets and the others for 135 gr.
I've been working through the 9mm cases on hand, which were separated by brand. The 135 gr. bullets presented no issues with all other brands of cases.