New 300 RUM build


Well-Known Member
Apr 3, 2009
Here is the newest member of the LR family. This one has been in the works for a while and I finally got the pieces together to finish it up. I had the guys down at Northwest Action Works do all the assembly once I had the parts in hand.

Build specs:
300 RUM
28" Krieger 5R
Manners EH1
Stiller Predator action
Jewell trigger
Nathan Wright (IdahoCTD) brake
Vortex Razor 5-20 EBR2B

I've had the time to work a load for it and in less than 50 rounds trying three different powder combinations with the 230 Hybrid target I got something I can live with. It absolutely loves 85.2 grains of H1000 in Norma brass with a Fed 215M. Here is the picture of the rifle and a target I shot at 575 yards with a slight left to right breeze to finalize seating depth. I worked a little with Retumbo and RL33 to see what I could come up with, but nothing jumped out at me.

I always find it interesting how much .005 difference in seating depth can make. The first series I shot was the top left at 3.075" Base to ogive. The next series was the top right at 3.070" with a dramatic reduction in group size. The others were varying depths that tested well at 150 yards that I wanted to verify at longer range. The 3.065" group displays the least amount of vertical with a group that measures right at 2.5".

A couple of you guys asked about what happened with RL33 in this rifle and think I found an RL33 combo that I can work with in this rifle. I tried it in Norma brass instead of the R-P brass I was originally using with RL33. I had better velocity with the R-P I just couldn't get the groups to tighten up. So I dropped a couple grains from my R-P max of 97.5 and loaded up a series starting at 94.5 in Norma brass. I seated them to .005 off the lands at an OAL of around 2.905". The sweet spot was 94.5 grains producing 3040 fps and single digit ES for the three shots I fired. Here's the group fired at 150 yards. Next week, I'll take her out to 575 and see what it does.

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