Compressed loads in 300 WM


Well-Known Member
Oct 17, 2011
Bare with me, I know there are lots of numbers in this post, but feel its neccessary to convey what I have going on.
I was approached by a friend to help work up some loads for his 300 WM, which is a Ruger M77 with a 24” barrel. He had been shooting 180gr factory ammo, but wanted to switch to a 200gr Nosler AB for an upcoming elk hunt. So we began searching for some 200gr AB’s and some H1000. He said he had been saving quite a bit of fired brass over the years, so we didn’t worry about buying new, and he still had a few hundred Federal 215 primers to work with.

We just got powder and bullets in last week, so I started the process. In going through his brass, most of it was nickel plated, and I have not read great things about trying to reload using nickel plated brass. So I sorted through all of the non plated brass and sorted it by head stamps. I had 44 Remington cases to start with. I tumbled, bumped the shoulders back using a FL die, then trimmed/prepped them all to 2.611” using a Frankford Arsenal Platinum Series Case Trim and Prep Center.

When measuring his chamber I was getting 2.960” to the lands. So I was going to back off .010” to run a pressure ladder using 2.950 CBTO. However, this gave me a COAL of 3.590”, and the internal dimension of his magazine is 3.435”. So we elected to back .035” off of that and loaded them to 3.400” COAL, which was 2.760” CBTO.

The Nosler load data for the 200gr AB and 200gr PT show MAX charge of 78.0gr of H1000 and notes that it is a compressed charge. My pressure ladder I loaded 74.0gr to 78.5gr in 0.5gr increments. Initially I seated them all long at -.010”, or 2.950” CBTO, and only noticed the slightest bit of crunching starting on the 78.0gr and 78.5gr charges. However, when I realized these were far from fitting in the mag, and had to seat them deeper, I noticed crunching starting with the lowest charge, and getting worse all the way up thru the highest charge.

The thing that baffles me is that the recommended COAL in the Nosler manual is 3.340”, which is .060” shorter than what I seated these too, meaning I would have slightly more room in the case. I would not have expected to feel the kernels until I got up around that max charge of 78.0gr, but this was not the case. I even saw my CBTO growing by .002”-.003” with each 0.5gr step once I got up to about 76gr or so. I ended up adjusting the seating steam a couple more thousandths each step to keep them as close as possible to the target CBTO of 2.760”

Wondering if anyone has had similar experience with any other long bullets and H1000 in the 300 WM? I will say, the powder in the 78.5gr charge was not up into the neck, but would say somewhere close to the bottom f the shoulder, maybe just getting up into the shoulder. Not sure if it is normal to have to adjust the seating die to get matching CBTO when doing a pressure ladder like this, I do not have a lot of experience with compressed charges. I’m guessing there is a difference between getting into the kernels and feeling them, and a true compressed charge? When I shake these loads next to my ear I can still hear the powder just barely shake around in the highest 78.5gr loads, but just barely at all.

Thanks for any insight you all might have on this. Let me know if there is additional info that would be helpful.


Well-Known Member
LRH Team Member
May 30, 2018
New York
Compressed loads have no impact on accuracy my 300 win loads are compressed. You will have to adjust the die once in awhile because you need to push down harder to push the bullet harder. No big deal.