Why would brass shoulders stop moving forward?

[BoydAllen]

It’s not a very stout charge. 30.4 of h4895. I’d tested up to 32 grains with no pressure signs but this had the speed where I wanted it and most consistent grouping and velocity spreads. So it sounds like it’s a combo of light load, work hardened brass and good die to chamber fit. Grouping hasn’t suffered so I’m not worried about it just curious.

Just for fun, load one up to your safe maximum and let us know what happens to the case's shoulder to head dimension.

 

[rwj]

It’s not a very stout charge. 30.4 of h4895. I’d tested up to 32 grains with no pressure signs but this had the speed where I wanted it and most consistent grouping and velocity spreads. So it sounds like it’s a combo of light load, work hardened brass and good die to chamber fit. Grouping hasn’t suffered so I’m not worried about it just curious.

I’m envious! Only shooting 29.3 grains of Varget in a 6mm Norma BR and my Lapua shoulder case length grows .002/.003” with each firing... doesn’t matter if they’ve just been annealed or on their 4th firing...