I recently worked up a load for .40 S&W major. My goal was 960fps to make major with a little cushion. These are fired out of a Glock 35.
Load fired today:
180 grain MG JHP
CCI SP primers
4.7 grains Titegroup
I tried working up to 4.6 grains but velocity was around 920fps. I loaded up some with 4.7 grains. I got velocities from 950fps to 1000fps today. I shot 20 rounds. I took the cases home for a little more detailed inspection. One case split. Almost all of them have a mark at the mouth of the case. Looks almost like a file swiped the case at the case mouth. The grain of the mark wasn't running the length of the cases but around them. The 4.6 grain load didn't do this. I shot some factory ammo at a match between the 4.6 and 4.7 grain load testing. I can't see anything wrong with the chamber. I've posted some pictures below. Thoughts?