FarmallSM
Gold $$ Contributor
Just getting into F class and chose to chamber new gun in 7mm x 6.5PRCC. That’s a 6.5 PRC necked up to 7mm. Shoots 180 Berger Hybrids @ 2900 ish.
Bought 300 rounds of new Lapua 6.5 PRC brass. 100 round boxes. I kept together in lots 1,2&3.
Fired 200 then annealed, sized then measured checking for over all case length. I’m using the 6.5 PRC case dimensions of 2.030 max length and would typically trim to 2.020 as needed.
Measured lot #1. All cases measured between 2.015-2.019 with most at 2.017. Very consistent.
Measured lot#2. Measured from 2.000-2.021 and every thing in between. WTF!
Measured lot#3. Fired but not processed yet. Measured 2.012-2.015. Again very consistent.
All three lots shot 1/4-1/2 moa @100 when I can hold the gun still. All lots shot 1/2-3/4 moa 20 shot groups @300 yds.
My .003 shoulder bump is +- .001 on both lots. Very consistent!
I’m not willing toss that expensive brass. I’ll load it again and see how it shoots. I have to believe it came like that from Lapua. It shot just fine. I don’t see how my process could induce that much variation in just that lot. Same press, same session, same dies etc.
The big question is should I trim lot 2 to some consistent length. Leave it alone? My 1st thought was to trim it all to 2.000.
Thoughts?
Bought 300 rounds of new Lapua 6.5 PRC brass. 100 round boxes. I kept together in lots 1,2&3.
Fired 200 then annealed, sized then measured checking for over all case length. I’m using the 6.5 PRC case dimensions of 2.030 max length and would typically trim to 2.020 as needed.
Measured lot #1. All cases measured between 2.015-2.019 with most at 2.017. Very consistent.
Measured lot#2. Measured from 2.000-2.021 and every thing in between. WTF!
Measured lot#3. Fired but not processed yet. Measured 2.012-2.015. Again very consistent.
All three lots shot 1/4-1/2 moa @100 when I can hold the gun still. All lots shot 1/2-3/4 moa 20 shot groups @300 yds.
My .003 shoulder bump is +- .001 on both lots. Very consistent!
I’m not willing toss that expensive brass. I’ll load it again and see how it shoots. I have to believe it came like that from Lapua. It shot just fine. I don’t see how my process could induce that much variation in just that lot. Same press, same session, same dies etc.
The big question is should I trim lot 2 to some consistent length. Leave it alone? My 1st thought was to trim it all to 2.000.
Thoughts?
