375 Whelen Improved

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  • Last Post 12 July 2018
delmarskid1 posted this 14 October 2015

I have a 375 Whelen Improved with a 14” twist. It's on a military Cz98 formerly based in Turkey without the goofey thread tenon that the Turks sometimes have. It's nice, needs to be blued yet but you know how that goes. To the point, where do I go to find cast data? I've looked at 375 Scoville and 9.3X63 data. I've been using 32g of Accurate Arms 2200 but I want to find something cleaner. It likes the Hornady 270 spire point very well. I have the Lyman mold that weighs 245 with a gas check. It feeds pretty balky.The meplat digs in at the base of the chamber. I worked the rails out as far as I dare. She takes those 270's out of the mag like a Krag. I've heard the thing about the head space problems and have decided it's bunk. It has way more space to catch the shoulder than a 45 acp. I'm just throwing this out here because I never hear of anyone using this caliber. I have a 375H&H as well. 

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bullshop posted this 12 July 2018

Slower powders coupled with heavy bullets.

 

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delmarskid posted this 12 July 2018

I need to get to work on my 375. I'm going to look at the slower powders.

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bullshop posted this 12 July 2018

I am a fan of the 375-06/Whelen.  I have two a rifle and a carbine. The rifle is a pre war Husky with 28" barrel and the carbine is an 1903-a3 with 18" barrel.

I have used the rifle to hunt caribou with excellent results.  Being an Elmer Keith fan I like heavy bullets so designed a 370gn bullet for use in these rifles. This bullet from the rifle with a load of 53.2gn of IMR 4320 at an MV of just slightly shy of 2200 fps is a caribou slayer. I shot one large bull right at dusk using iron sights so aimed at the shoulder on about a 75 yard shot and found that the impact of this big WFN type bullet had caused both antlers to be thrown off the bull and were lying a couple steps behind where the bull fell. It also made a fist size exit hole. Like Elmer said, " bring enough gun" and I did.

When I read some years back about the then new 9.3mm magnum cartridge from Norma shooting a 280gn bullet at 2400 fps I set out to duplicate that load in the 375 Whelen and I did accomplish that.  For this I used our 286gn 9.3mm round nose bullet paper patched to .377" diameter and achieved the desired goal of 2400 fps with very good hunting accuracy. The load burned 56.9gn IMR-4320 and has a very tight extreme velocity spread from the rifle.

Another favorite load for the big 370gn bullet is 57gn IMR 4350 for a very consistent 2075 fps.  This is an acceptable load where I live now in Montana. No longer living in Alaska and contending with brown bears the lesser recoiling load with 4350 is plenty.

The highest velocity I have obtained with the 370gn bullet in the 375 Whelen was with 57gn WC-844 that went to just a few fps shy of 2290 fps but that seemed like too much of a good thing.  Extraction was normal but recoil was becoming distracting.  My pretty much standard load with the 370 bullet is the 57gn 4350 for 2075 fps as it shoots good and not too much for my aging shoulder.

I started on this road first with the 375 Hawk/Scoville in a pre 64 model 70 and the thing just would not feed dependably.  I then went to the standard Whelen case and found it feeds absolutely reliably in both the Husky and Springfield actions and I have not encountered any headspace issues with the less defined shoulder angle. 

Another thing I found is that with the heavy bullets I use there was little to no velocity gain using the improved type Scoville case over the standard Whelen case because of the deep seating required of the bullet base negating any case volume increase.  At the same OAL with this long 370gn bullet both cases have about the same volume.  Since the standard case feeds so well and since living in brown bear country feeding was an important issue so the standard Whelen became a member of the family. 

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delmarskid1 posted this 18 February 2016

Fg1 wrote: I use 4320 in my 375-06 AI for cast and jacketed .Cast I use a Lyman 375449(?)that throws a 270 gr Lyman #2 ish bullet. I have some 300gr cast from one of Toms molds which I havent had a chance to put them on paper . The jacketed Horn 270 Ive chronied at 2550 fps and is accurate .

For the 375-338 WinMag Ive been working with 3031 as fuel and 300 gr cast with babbit sweetener and water quenched  from mold. So far so good :) Thanks, I've used 4320 with the hornady 270's and they shot very well and killed a deer very dead. 

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Fg1 posted this 16 February 2016

I use 4320 in my 375-06 AI for cast and jacketed .Cast I use a Lyman 375449(?)that throws a 270 gr Lyman #2 ish bullet. I have some 300gr cast from one of Toms molds which I havent had a chance to put them on paper . The jacketed Horn 270 Ive chronied at 2550 fps and is accurate .

For the 375-338 WinMag Ive been working with 3031 as fuel and 300 gr cast with babbit sweetener and water quenched  from mold. So far so good :)

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delmarskid1 posted this 09 November 2015

I loaded twenty rounds with the lyman 260g bulles that I had on hand over 27g of IMR 4198. 25.5g is supposed to give about 1700 fps in the 375 winchester cartridge. They weren't particularly hard cast. Made up of my black powder cartridge alloy. They shot pretty well. I use a 1 to 4x shotgun scope and got shots two inches apart at 150 yards while sighting in. It's sends them about an inch high at 50 yards and 5” low at 150 yards. I've made another 20 rounds to try but I've gone to 28g of IMR 4198 to get a little less trajectory. The gun kicks about like a factory .308 Win.

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delmarskid1 posted this 15 October 2015

Thanks you guys. I figured this thread might run thin I had not considered H414.

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rockquarry posted this 15 October 2015

I haven't had a .375 Whelen Improved in years, but still retain old load data in my notes. Got good accuracy with the SAECO 250 grain gas check flat nose and 52 grains H414. Bullet alloy was approximately Lyman #2, bullet sized .379". I have data for a couple of other bullets, each over 300 grains.   

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onondaga posted this 14 October 2015

H4895 and Varget both burn very clean in the Whelen and both have nice pressure curves for cast bullets. I use those powders in 375 H&H for the same reason.

Just find the sweet spot!

Gary

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