Just a thought:
1. One batch of all the same brass, 50 pieces. 25 with factory flash hole, 25 with enlarged flash holes.
2. Same powder charge, same bullet, same primer in both sets of 25 pieces.
3. Do random rows of five rounds in your ammo box - one row of five rounds is factory flash hole, another row is enlarged flash hole, and so on. BUT, have a third party load the box and not tell you the pattern.
4. Go shoot ten groups with the loaded ammo box, see if you can tell a noticable difference in group size then.
I loaded up 25 more rounds with 24.4 grains of 3031 and I found my CCI 400 primers. I had one more sleeve left. Now I have the ammo I loaded in 2019 with the undrilled primer holes and the ammo I loaded today with the drilled primer holes. Although the brass will be mixed but it is mostly 5.56 Lake City and 5.56 Winchester. I won't have the third party. It will just be me. It will be next week before I get to shoot them. Our local range is muy busy on the weekends.
kwg
