Heavy 375 Loads

[NM-375]

I have read that the 38-55 got it's rep with a 250gr bullet. I feel my WINBB should be able to better that. Has anyone worked up loads for either the 270 or 300 grain jacketed bullets? I realize I don't have the case capacity of the 375 JDJ (375x444), but this should be doable, should't it?

[1886]

What/whose bullets do you propose? Regards, 1886.

[JFE]

They're not jacketed but I've worked up loads for cast bullets of that weight. I've pushed a 300gr cast to over 2000 fps but it works better at 1800 fps. This is using 375 brass. The cast bullet I'm using is CBE 376300 (Aussie mould) and it has the crimp groove in the right place for use in the 375 Win.

Lyman's 375449 weighs around 278gr when checked and lubed but crimp groove location is more suited to 38/55 brass. I've had this bullet to 2200 fps but best accuracy was around 2000 fps. With cast I think a larger case would provide lower pressures and quite possibly better accuracy at higher speeds. This is something that I am finding with cast out of my 348 Win.

In the 375 Win the best powder that I've tried so far has been Reloader 7, but understand that AA1680 is better. Unfortunately we dont have that powder available down under.

HTH

Joe

[1886]

You had mentioned jacketed rounds in your post, hence my question. I have worked with 335gr cast projectiles in a Marlin CB .38-55. Velocity was right at 1500fps. Accuracy was excellent. Unless I was looking for a close range "penetrator" load for heavier game I would probably opt for projectiles in the 250-278gr vicinity. They are better balanced. A 300gr projectile at 2000fps is certainly "humping it". You did not mention your platform. I have experience with the Marlin .375, the Win. 94 .375, and the Marlin CB .38-55. If loading for the Marlin .375 and or the Win. .375 I would use the Starline "short" .38-55 brass. I would avoid 1680. Others on other forums have touted the virtues of 1680. The burning characteristics/rate is inappropriate. RL-7 is much preferred for high performance loads. Modern guns only please. Velocity with the longer cases will not improve markedly as one is still restricted to the same O.A.L. The longer case will occupy more of the available chamber area. I prefer the CCI BR-2 primer. My thoughts rambled a bit but I hope I helped. 1886.

[Kapincrunch]

1886,
you mentioned the "burning rate with 1680 not being appropriate." Do you mean for heavier bullets? I have not reloaded my 375 yet but was leaning toward using 1680 and 200grain bullets. Mostly because the extra fps at no cost in pressure. I also have heard that the 2 best powders were Reloder 7 and 1680. I may give H322 a go as well since I have some on the shelf. Any additional thoughts would be helpful. Sorry, didnt mean to hyjack the thread. Just thinking powder thoughts.
Jim

[Griff]

I have only loaded the 220 Hornady bullet for my Marlin 375, but after experimenting with a lot of powders found RL-7 gives the best accuracy at the highest velocities. For lighter or heavier bullets I don't have an opinion. I only used 375Win brass as that was all that was available at the time and have stuck with WLR primers as neither BR or magnum primers showed any improvements in my testing when I first got the rifle back in 1980.

[1886]

1886,
you mentioned the "burning rate with 1680 not being appropriate." Do you mean for heavier bullets? I have not reloaded my 375 yet but was leaning toward using 1680 and 200grain bullets. Mostly because the extra fps at no cost in pressure. I also have heard that the 2 best powders were Reloder 7 and 1680. I may give H322 a go as well since I have some on the shelf. Any additional thoughts would be helpful. Sorry, didnt mean to hyjack the thread. Just thinking powder thoughts.
Jim

Jim, In response to your question. 1680 is very temp. sensitive. It is also very dirty. Being a ball/spherical powder that is considerably deterred, requires/mandates considerable load density to avoid the very real and unpleasant possibility of detonation. Caution/prudence dictates a very minimum of 90% load density. 100% and better yet 105% load density/5% compression is best. I do not know if 1680 is operating at safe pressures at this level of compression. One could assemble a starting load and a max. load utilizing 1680 taken from a reputable/recognized manual using the exact components outlined in
said book. What is the load density? Can you shake the loaded round and hear the powder moving in the case? If so, it SHOULD BE AVOIDED. It is for these very reasons H-110/296 starting loads should never be reduced. I use H-110/296 as caution examples because they are well known and the reduction of these powders is always best avoided. Commonly available better
powders would include RL-7, 2015, H-322. Hope I was clear. 1886.

[NM-375]

Hey, 1886. I will be trying the Hornady RN 300 and the Remington RN 270. Just happen to have a few hundred lying around. I hunt black bear and elk here in NM.
Eric

[1886]

I am not very familiar with those bullets except I believe they were designed around the performance capabilities of the H&H round. The Hornady 220gr bullet has an excellent rep. in the .375 Win. I would suggest the Lee factory crimp die. They make one for the .375 Win. and the "short" .38-55. Cannelure(sp?) position is not as critical with the Lee FCD. I would suggest the shorter .38-55 brass. Not certain of the brass you are using. I would also use an expander that is .005" smaller than the projectile diameter. It is probable others have tried what you are attempting but you will in all likely hood not find data. What is the groove diameter of your rifle? The bullets you mentioned are .375". Good Luck, 1886.