Fellow members,

I finished load development for my new 375 RUM. Here are the details.

R-R Brass, 270gr Barnes TSX
H4350, CCI LRM primer
COAL: 3.585 inches

The rifle has a 24 inch match grade pacnor barrel in a 1/10 twist. I started low as per Barnes reloading manual. The start charge was 88g of H4350 and I went up in 1gr increments all the way up to the 96gr limit. I loaded 5 rounds of each to see which shot the best. The start charge gave velocities averaging 2800 fps but the groups were nothing to brag about. I finally found her sweet spot. 95.0gr of H4350 gave me the following results.

Shot 1, 95.0gr H4350: 2888 fps
Shot 2, 95.0gr H4350: 2892 fps
Shot 3, 95.0gr H4350: 2898 fps
Shot 4, 95.0gr H4350: 2898 fps
Shot 5, 95.0gr H4350: 2900 fps

Average 5 shot group was 5/8 of an inch at 100 yards.

96.0 gr of H4350 started opening up the groups again.

I will post pictures when I get back home.

Maurice

Sounds good! I've read that H4350 is THE powder for the 375 RUM...sounds like it certainly is in your rifle.

Hello Ongwe,

With my very limited experience, I would have to agree that H4350 works well with the monolithic bullets. I think H4831 will also be a very good powder with the traditional cup and core bullets.

i had really good luck with 7828ssc with the 300 tsx bullets. It is reall accurate and shoots flatter than i thought it would.