rap36case
Working up loads for new Shilen 308win
I moly coated some Sierra 210 MatchKing 308Win by a modified NECO process. I cleaned everything first with dishwashing soap with degreasing components and dried with a hair dryer. I heated the steel shot with a hair dryer and added moly to condition. Then, I warmed 50 bullets and coated them for 2 hours. Next, I polished with corn husk and a few grains of wax. They came out a matte grey and very smooth.
I trimmed my WW brass to 2.010, turned 0.012" neck wall, tension 0.330". Cleaned with corn husk and wire pocket brush. Primed with CCI BR2 and handheld RCBS primer. The IMR 4064 was dispensed and then weighed from 39.0 grains in 0.2 grain increments up to 41.0granis. I Seated the bullets to 2.220", as this is what my CZ550 Varmint likes. I also use Smooth Kote in the barrel to match moly to moly each time I clean the rifle.
I took 40 rounds to the 300yard range and measured with Chrony. I got very tight groups of 1" from 39.2 at 2350FPS average all the way up to 40.0 grains. From 40.2 to 41.0, the groups were less tight of 2" and 2400 fps average.
I found that these rounds were also accurate at 500yards and showed little instability at this distance, despite the 15mph 5 O'clock wind at 47F. I was getting head shots on the silhoette at 500.
I have concluded that 39.6grains is a good choice from this ladder. I will conduct a ladder from 41.0 to 42.0 at 0.2 grain steps. According to Litz, 2449fps is a good velocity for the Berger 210 with 0.321 G7 and very accurate out to 950 yards for a 10 inch vitals area on 150LB game.
I expect that beyond 500yards, there will be some instability in the CZ550 with 1 to 12 twist. I will revisit the load with my Shilen 1 to 10 when it arrives.
This seems to disprove the assertion by Sierra that this bullet is not for 308Win. Berger includes reload data for 308Win for there 210g and higher offerings. I understand people have been using heavier bullets at Camp Perry since the 60s.
I trimmed my WW brass to 2.010, turned 0.012" neck wall, tension 0.330". Cleaned with corn husk and wire pocket brush. Primed with CCI BR2 and handheld RCBS primer. The IMR 4064 was dispensed and then weighed from 39.0 grains in 0.2 grain increments up to 41.0granis. I Seated the bullets to 2.220", as this is what my CZ550 Varmint likes. I also use Smooth Kote in the barrel to match moly to moly each time I clean the rifle.
I took 40 rounds to the 300yard range and measured with Chrony. I got very tight groups of 1" from 39.2 at 2350FPS average all the way up to 40.0 grains. From 40.2 to 41.0, the groups were less tight of 2" and 2400 fps average.
I found that these rounds were also accurate at 500yards and showed little instability at this distance, despite the 15mph 5 O'clock wind at 47F. I was getting head shots on the silhoette at 500.
I have concluded that 39.6grains is a good choice from this ladder. I will conduct a ladder from 41.0 to 42.0 at 0.2 grain steps. According to Litz, 2449fps is a good velocity for the Berger 210 with 0.321 G7 and very accurate out to 950 yards for a 10 inch vitals area on 150LB game.
I expect that beyond 500yards, there will be some instability in the CZ550 with 1 to 12 twist. I will revisit the load with my Shilen 1 to 10 when it arrives.
This seems to disprove the assertion by Sierra that this bullet is not for 308Win. Berger includes reload data for 308Win for there 210g and higher offerings. I understand people have been using heavier bullets at Camp Perry since the 60s.
