My OCW Test

Reloading equipment, methods, load data, powder and projectile information.

Re: My OCW Test

Post by sungazer » 17 Jan 2018, 11:25 am

Just another part of the load development which I think affects group size more under most conditions is seating depth. In the picture below I started with seating depths of what I thout was on the lands then at 15 thou off,25,35,50 and 60. After looking at the results I when back and decided to try harder and be more precise with my 0 or on the lands seating and removed the ejector spring in the bolt to get a better feeling. The reason for this was that the 25 thou off if it was that didn't fit the pattern I would expect. As it turned out I was correct and the 25 thou was some touching and some not. There is about 4 thou tolerance in seating the bullet. and the 0 and 15 were in fact jammed.
Anyway I adjusted the dies and decided to re run the tests. These are all using 308 Berger 155 hybrids. I would have liked to see the point in which the groups opened up it looks like the Hybrids are very tolerant to seating depth. I did the second test at 0,20,40,60 and 80 thou off the lands. The second test are the groups on the top.
From this I think I will seat them 50 thou off as 40 and 60 are pretty good and that gives room for any tolerance issues.
IMAG0197.jpg

I was also testing a firm recoil hold vs a free recoil the first groups shot free recoil then I shot a group the same day in the bottom middle using a firm recoil hold and found it was not any worse but keeps the rifle more on target. The second test was all done with a firm recoil hold. Just to see if any more fliers appeared. It is important to keep the conditions all the same as there is a difference in POI from free recoil to soft hold to firm hold to grip as hard as you can.
sungazer
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