Well I have finally found some time to get out and try some loads in my custom STW.
I went through the barrel break in process a while ago, but hadn't really spent much time on load development. I had worked up loads testing for pressure signs and recorded velocities, but none of the loads were grouping well at all.
The magazine will allow an OAL of 3.785" so that's where I was working from.
For a new custom rifle. (Krieger Barrel) I was getting a bit disappointed with the groups I was seeing. 2 - 4" groups at 100 yards.
So this week I went out and tried the same load in 3 shot groupings, each decreasing the OAL by 0.020"
I was really surprised with the results.
Nosler Custom Brass twice fired
Federal Match Primers
Hodgdon H1000 powder 81.5 gr
Matrix 168gr VLD bullets
Starting OAL was 3.785", tested down to 3.7585"
The groups started at close to 3" @ 100 yards, but with each decrease of .020" in OAL the groups shrunk, until 3.705" the group was approx. 3/4" then it started to open up again.
So it looks like the 3.705" load it what I will work with from here.
It surprised me how much varying the OAL would change the groups.
Velocity for this load is 3240 fps average, with ES of 11. (only 3 loads fired)