I'll be loading 300 grain Trophy Bonded Bear Claws. I checked Speer's site and they have loads using H414, IMR 4064, IMR 4350 (and 4895), RL 15, and AA 2700. I've been using RL-15 for my 470NE, so I have some of that, but I'm open to using anything that has proven success. Have a favorite load that has worked for you?

Since you already have RL15, I'd try it first. With a 300 grain, somewhere around 69-72 grains should give 2500 fps, depending on your rifle. I see some are loading 72 grains of RL15 with a 300 grain bullet, but it's way too much in my rifle.

jstevens,
Speer says that 70 grains of RL-15 is the max load, so I can see that 72 could well be pushing it. I'll try 69-70 and see how it goes from there. Have you tried any other powders besides RL-15?

Bullet: Sierra 300 Grain Spitzer Boat Tail
Powder: 78.7 grains of IMR-4350
Primer: Remington 9-1/2M
Case: Winchester
Firearm: Ruger #1
Optics: Leupold 2x7
Velocity: 2,596 FPS @ 15' from muzzle
Accuracy: 3-shot, 1" groups at 100 yards

77 grains of IMR 4350 normally works well, as does approximately the same amount of H414 with a 300 grain bullet. Another old reliable is IMR 4064. You'll load maybe a grain less powder of 4064 than you use of RL15. In general if RL15, 4064 , 4350 won't shoot in a .375, the rifle won't shoot with anything. Seriously, I've never owned a .375 that didn't shoot well. Must be that short fat powder column that makes it work so efficiently!

jsteven:

quote:

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Since you already have RL15, I'd try it first. With a 300 grain, somewhere around 69-72 grains should give 2500 fps,

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Yup.....and I second that.

W-W case, W-W magnum primer, 77 grains of W760, with any 300 grain bullet. Duplicates factory and is super accurate. W760 is a ball powder and meters like sand and costs $99 per 8lb.

one of my favourite loads for .375 HH is 82 grs of Norma 204 and 300 grs Nosler Partition: is very accurate and the effect on game is really 'one shot kil' (depending on shot placement... )
One more good accuracy load is 72 grs of VitN140 and 300 grs Barnes X FB.
Both loads have Vo close to 2.650 fps.
Have a great hunting day, ciao

These all sound like some great loads. I think I'll start with the RL-15 load since I have the powder ready to go, and I believe I already have some IMR 4350 that I'll try as well. I'm sure I'll experiment with some of the others over time.
Thanks!

My Ruger RSM .375 likes the 300gr Hornady RN over 67.0gr of IMR-4064 and a CCI200... This gives me 2500fps and shoots dead-on with my express leaves. I wouldn't use this bullet on heavy game (too fragile from what I've heard), but it's an excellent and affordable plinking bullet and for deer, elk and like-sized critters it's fine.