The Firing Line Forums - View Single Post - Large Rifle Primers

Rimfire5 · December 4, 2022, 08:38 AM

Another bit of information for what it's worth.

Years ago, when I was trying to determine if using magnum primers in the bitter cold weather would improve performance, I tried large rifle primers and large rifle magnum primers with the same loads with my .30-06 and my .270 Winchester rifles.

I used the same loads in each to be able to see the difference.
Using my Ohler 35P to measure velocity, on a 31-degree day in the middle of winter here in Northern VA, I shot both rifles with both primers and measured the velocity.
Using magnum primers increased velocity by 12 fps on average over 10 rounds with each type of primer.
I didn't see a measurable difference in group size averages.

December 4, 2022, 08:38 AM	#11
Rimfire5 Senior Member Join Date: January 2, 2009 Location: Northern Virginia Posts: 923	Another bit of information for what it's worth. Years ago, when I was trying to determine if using magnum primers in the bitter cold weather would improve performance, I tried large rifle primers and large rifle magnum primers with the same loads with my .30-06 and my .270 Winchester rifles. I used the same loads in each to be able to see the difference. Using my Ohler 35P to measure velocity, on a 31-degree day in the middle of winter here in Northern VA, I shot both rifles with both primers and measured the velocity. Using magnum primers increased velocity by 12 fps on average over 10 rounds with each type of primer. I didn't see a measurable difference in group size averages.