This is my 1st post here. It is not news that reloading supplies are limited to say the least. I have a somewhat simple question but have not found any direct answers on the links here, ( or anyewhere else) please redirect me if I am wrong. I am an experienced reloader (35+ years but trying to get the science of it down), but with mainly pistol and smaller rifles that are more recent & popular loads that there is a ton of published data for. I am most likely over thinking this, but here it goes.
1. I have a great Pre-64 Model 70 in .375 Weatherby Magnum I inherited from my Dad. I really want to use it on a hunt this year. It is a field grade hunting rifle, but Factory Ammo is out of the question - 6 bucks a round and only in 300gr - OUCH on the Shoulder and Wallet - really bad!
2. I have multiple manual (including recent One Book / One Caliber). Have been web searching but all sources only give data for Hodgdon Powders.
3. After much waiting in lines (mostly left stores empty handed) I was able to get 1 lb. each of some IMR 4350 and IMR 4831. I am trying to work up loads with Hornady Interlock SP 225 gr. (4350) and Hornady Interlock SPRN 270 gr. (4831)
4. Unless I find some 215 primers I am stuck using Remington 9 1/2 Large Rifle Primers. I just fire-formed & Weighed New 375 H&H Hornady Brass as well.
4. Does anyone have a formula or something I can use to set myself up with starting loads for a conversion? With the pretty heavy recoil and lack of reliable supplies I cannot afford to test shoot dozens of work up loads from way too weak to acceptable. Plus do not want to break myself or the Rifle - safety 1st.
5. I have checked other Magnum Rifles for comparison, my Manuals show about a 9-10% reduction for IMR 4831 in a 378 Weatherby with a 270gr. And about a 2-3% Reduction for IMR 4350 vs H4350. Thus my plan is to use the same % in my 375 Weatherby Hodgdon Data.
6. I am thinking right? I am not looking for MAX loads, but accurate Hunting Loads to 400-500 yards.
I have found more than one thread about the pros and cons of both powders, and about Magnum vs STD Large Rifle primers, but not comparisons of load amounts. Since I can not find any other powder I can not use the testing I have always used in my other guns. Plus at 90ish grains per load I get only about 75 reloads out of a pound.
Thanks for all the great reading on other posts and hope we all get tags this year and have ammo to use them!
I would normally only use magnum primers, but in N. Nevada I have not seen any in 6 months. It is like getting Concert Tickets at my local shops, 300 plus people in line 90 minutes before stores open the day after they get stock. Thus my Large vs. Magnum dilemma + Powder choices are so limited to seem like I am shopping in the old USSR. No gun ban needed if you can not find ammo or reloading supplies, it does not make a good club.
If I make the draw 225 gr for Mule Deer, 270 for ELK - Ok I know these are a bit of overkill, but this was my Dad's Gun that I have loved since I was too little to shoot it and really want to use it and share the harvest with him while He is still here. His health is not so good and would like to put a big smile on his face knowing "HIS" rifle did the job.
The 225 at a light loading of 2900 FPS at 5000+ ft altitudes here in N. Nevada that leaves me with over 1600 ft.lbs and 10.3 moa drop at 500 yards
Last edited by MikeMarcum; 04-25-2013 at 02:36 PM.
Reason: More info
have loaded the 375hh and 378 wm. we have taken elk , zebra and other stuff with the 270 horn sp. i used varget in the 375hh ; my buddy shot a lot of animals with it. can not remember what used in the 378 neither were my guns. weatheerby IMR , nosler hogdon someone has data. dont extrapolate. you may get more info over on 24hourcampfire. luckily you are not hunting next week, mean time find some mag primers. ron
The most likely problem you will have with the 375wby/225grn/4350 load is you will run out of powder space, same with the 270grn/4831 load. The 225 load would do better with Varget, 4064, 4320, 4007ssc, etc.. the 270grn load would be top notch with Imr 4350 and a standard primer will light off 4350 or 4831 just fine, although with that much powder I do prefer WLRP as they are about the hottest standard primer except the russian wolf/Tull stuff. Both of your loads will be highly compressed with your powder options. The 375 H&H calls for a compressed load of H380 under a 235grn pill and it operates 3k psi lower than the wby, just as an example.
One again, Thanks for the info. If and when I can get any other powder I will as well as Magnum Primers, if and when the supply chain returns to semi normal. I think the IMR 4831 will not be as bad as H4831 as the load will be decreased 10%.
I am not planning on using 378 load data, just looking at something else big that has load data for both IMR and Hodgdon powder and ratios they are using. Trying to figure out good starting point for what stuff I can find.