375 Whelen Improved?

It sure seems like a headache of a project when there are so many equivalent or better solutions.
@Challer
Being a wildcat owner where's the fun in having the same as everyone else. We like re-inventig the wheel. Sometimes it's a better wheel, sometimes the same as other wheels and sometimes a worse wheel.
But it is fun a good way to learn about ballistics.
If people didn't experiment we wouldn't have some if the nice cartridges we do today.
Look at the Weatherby line. If'n it wasn't for a dreamer we wouldn't have those rounds .
We might not have the class as Roy but we have similar dreams
Bob
 
I have a Valmet 412 375 Win double rifle (currently being rechambered to 375 flanged), a Stainless Winchester Mod 70 in 375 H&H, and a Mauser 98 in 375 Whelen. They each have their strengths and weaknesses, and each solves a problem that the others do not. There isn't just one problem and there isn't just one solution to any given problem.

If I were going to a wet environment like AK and needed superior accuracy, I would take the stainless Mod. 70.

If I were wanting the quickest follow-up shot, I would go with the double rifle.

If I were wanting a DG rifle with the least recoil, cheapest most available components, superior accuracy, and the most ammo in the magazine without a reload, I would go with the 375 Whelen.

If I just want another excuse to buy another rifle, well I don't need much in that regard. I will buy a rifle at the drop of a hat, and sometimes I will drop the hat. But there was a time when I could only own one and finances would limit shooting. In those circumstances, the 375 Whelen would be the pick of the litter for a medium bore DG rifle. Of course in the US, for many decades I found very few problems I could not sort out with my trusty 30-06.
 
I'm quite new here. I started off with a .375 Whelen IMP back in the early 1980's. Id worked up a number of loads for it, aĺl recorded in one of my 3-ring binders of loads, then re-chambered the bl. With a 6.5x68 reamer to produce 9.5x68 chambering.(had to buy a Manson neck/throater) It ended up having 2gr. more capacity than the H&H. I worked up loads to 2,900fps with Hornady 270's. Then my buddy Keith wanted it so I sold it to him.
A few years went by and a friend wanted to read one of my books on wildcats. After that he wanted a .375/06IMP. We ordered the barrel from Bevin King, Pouce Coupie, B.C. The barrel arrived and as I still had brass from my first one, we pulled the bl. from an '06 Ruger lefty for Gord and installed and headspaced the .375Whelen Imp. bl. & he stared working up loads with dies from CH4D. I also ordered a bl. from Bevin, putting it on a Mk.10 Mauser action.
Working up loads commenced. I worked up to 2,472fps with 300gr. Interlock and Interbond, Sierra BT and Norma RN's using both H4895 & BLC2. As well as 2,740fps with H4895 with Barnes 270gr. TSX. I had worked up a ladder progression. Measuring heads and webs without anything bad. That's vels. frightened me when I finally chronographed those, so I cut the load 3gr. for a solid 2,650fps.
Excellent ctg. IMHO. I chronographed some factory 300gr. WW Silver Tips in a stock BRNO ZKK 602 for a local gun Smith at 2,474fps. I put his gun on the rack picked mine up and said watch the screens. I fired one shot with a 300 gr. Sierra BT with BLC2 and it went 2,472fps, then, with just my little finger, lifted the bolt and ejected the found catching it in the air.
Yeah, I like the .375/06Imp.
Mine has a .460" shoulder and a .470" base. Standard length neck.
 
Last edited:
My only experience is with the.375 Whelen (not Improved). 300 gr aframes took everything from wildebeest and zebra (400+yds) to eland and sable at over 200. 300 gr @ around 2400 fps.
 
I'm quite new here. I started off with a .375 Whelen IMP back in the early 1980's. Id worked up a number of loads for it, aĺl recorded in one of my 3-ring binders of loads, then re-chambered the bl. With a 6.5x68 reamer to produce 9.5x68 chambering.(had to buy a Manson neck/throater) It ended up having 2gr. more capacity than the H&H. I worked up loads to 2,900fps with Hornady 270's. Then my buddy Keith wanted it so I sold it to him.
A few years went by and a friend wanted to read one of my books on wildcats. After that he wanted a .375/06IMP. We ordered the barrel from Bevin King, Pouce Coupie, B.C. The barrel arrived and as I still had brass from my first one, we pulled the bl. from an '06 Ruger lefty for Gord and installed and headspaced the .375Whelen Imp. bl. & he stared working up loads with dies from CH4D. I also ordered a bl. from Bevin, putting it on a Mk.10 Mauser action.
Working up loads commenced. I worked up to 2,472fps with 300gr. Interlock and Interbond, Sierra BT and Norma RN's using both H4895 & BLC2. As well as 2,740fps with H4895 with Barnes 270gr. TSX. I had worked up a ladder progression. Measuring heads and webs without anything bad. That's vels. frightened me when I finally chronographed those, so I cut the load 3gr. for a solid 2,650fps.
Excellent ctg. IMHO. I chronographed some factory 300gr. WW Silver Tips in a stock BRNO ZKK 602 for a local gun Smith at 2,474fps. I put his gun on the rack picked mine up and said watch the screens. I fired one shot with a 300 gr. Sierra BT with BLC2 and it went 2,472fps, then, with just my little finger, lifted the bolt and ejected the found catching it in the air.
Yeah, I like the .375/06Imp.
Mine has a .460" shoulder and a .470" base. Standard length neck.
@Daryl S
So the 375 Whelen improved is doing with a 300 what the 35 Whelen is doing with a 310 gn.
Bob
20220618_081949.jpg
 
Or, close enough, Bob. The h4895 load only pushed the Sierra at 2,380fps. That's why it is listed with BLC2. I am sure that BLC2 load, with the 2 Hornady's and the Norma RN would have been well over 2,510fps. Not bad for an '06 case.
 
Or, close enough, Bob. The h4895 load only pushed the Sierra at 2,380fps. That's why it is listed with BLC2. I am sure that BLC2 load, with the 2 Hornady's and the Norma RN would have been well over 2,510fps. Not bad for an '06 case.
@Daryl S
In the Whelen the 257gn Woodleigh PPSP can be loaded to over 2500 fps. This bullet is the same in SD as the 286gn 9.3 and better sd than the 279gn 375.
Just saying
Bob
 
Moot point. I only hunt whitetail deer now. I have a new-to-me Mauser, DSTriggers, Swarovski 4x in claw mounts chambered in 6.5x57. 2,860fps with 120 TTSX is all I need now.
Cheers
 
You're all for necking up a .30/06 case to .375 and then adding the extra step of improving it, but necking up the WSM case to .375 and going shooting seems crazy?

As it turns out the .375 WSM is quite a pleasant and potent cartridge... I've been able to test it on moose and bears and will see how it does on PG in the near future.
Follow up... the .375 WSM did just fine in Africa... I have since switched to the 250 TTSX @ 3.050"...

20250307_151105.jpg
20250304_081740.jpg
20250301_111721.jpg
20250304_184657.jpg
20250303_083926.jpg
20250301_173004(0).jpg
 
Extra step? Both would have to be fireformed. Neck, fireform and done. I guess there is the extra step of necking down from straight. NP when you have either a turret press or 2 presses set up, as I do (both).
Your .375/.30WSM would work just fine. Mine does too. I even necked .270 Winch. brass straight in one pass without losing a case. I did lose some old, oft-fired .30/06(without annealing), about 2 in 10. found I liked the new .35 Whelen brass the best, as it ended up with thicker necks, not a biggie though. I'm still using .375/06IMP brass from the 1980's as well, in my older 9.3x62. I just necked them down in a neck-bored .300 H&H FL die I had in the bin to hold a .9.3 mm bullet and fireformed them in the 9.3x62. The original .375/06IMP had a .454" shoulder, same as my 9.3x62's.
 

Attachments

  • 375 06IMP case forming steps.jpg
    375 06IMP case forming steps.jpg
    240 KB · Views: 27
Last edited:
Extra step? Both would have to be fireformed. Neck, fireform and done. I guess there is the extra step of necking down from straight. NP when you have either a turret press or 2 presses set up, as I do (both).
Your .375/.30WSM would work just fine. Mine does too. I even necked .270 Winch. brass straight in one pass without losing a case. I did lose some old, oft-fired .30/06(without annealing), about 2 in 10. found I liked the new .35 Whelen brass the best, as it ended up with thicker necks, not a biggie though. I'm still using .375/06IMP brass from the 1980's as well, in my older 9.3x62. I just necked them down in a neck-bored .300 H&H FL die I had in the bin to hold a .9.3 mm bullet and fireformed them in the 9.3x62. The original .375/06IMP had a .454" shoulder, same as my 9.3x62's.
Yes... extra step. With the .375 WSM, I have one pass in the die, "NO" fireforming.. The Whelen AI requires that plus fireforming... the die doesn't make the case bigger...

20251221_132508.jpg
 
AND? Is this much extra "work" a problem for you? Incidentally, after necking the case straight, there is very little "enlarging of the case", more just ironing out the previous shoulder line. Fireforming loads shoot identically to formed loads, so no, no fireforming actually necessary.
 
AND? Is this much extra "work" a problem for you? Incidentally, after necking the case straight, there is very little "enlarging of the case", more just ironing out the previous shoulder line. Fireforming loads shoot identically to formed loads, so no, no fireforming actually necessary.
Fireforming loads almost never shoot identically to post formed case loads... unless your expectations are far lower than mine. I think you need to read the thread. My first statement was in response to being questioned on why I would build a .375 WSM... the irony was thick for this thread.
 
For me, the reason for making and shooting wildcats, is mostly THE process. The added benefits of improved performance in a particular calibre, is a bonus. I know how to do it, even with my own wildcats and I enjoy doing it, experimenting is fun. If the desired end is available with a store bought ctg., then there is no "fun" in that. Simply necking a ctg. is boring!
Each to his own.
 
For me, the reason for making and shooting wildcats, is mostly THE process. The added benefits of improved performance in a particular calibre, is a bonus. I know how to do it, even with my own wildcats and I enjoy doing it, experimenting is fun. If the desired end is available with a store bought ctg., then there is no "fun" in that. Simply necking a ctg. is boring!
Each to his own.
You're the hoss...
 
For me, the reason for making and shooting wildcats, is mostly THE process. The added benefits of improved performance in a particular calibre, is a bonus. I know how to do it, even with my own wildcats and I enjoy doing it, experimenting is fun. If the desired end is available with a store bought ctg., then there is no "fun" in that. Simply necking a ctg. is boring!
Each to his own.
@Daryl S
I know the feeling. It was like that with my 25
 
For me, the reason for making and shooting wildcats, is mostly THE process.
Totally agree. Most of the time I make up 100 cases, so even if they shoot different to the final case, you can still get some use out of them. Culling ferals for example.
Once you have the dies, it generally is not too difficult to form the cases.
 
Totally agree. Most of the time I make up 100 cases, so even if they shoot different to the final case, you can still get some use out of them. Culling ferals for example.
Once you have the dies, it generally is not too difficult to form the cases.
 
I have to ask why you used 300WSM brass instead of 325WSM brass. I use the 325 to make 35Sambar cases. Straight one step neck up and less work on the case, press and me.
I do the .300 WSM in one pass now too... initially I was going to .358 and then .375, but I have the same success rate in one step. When I was loading for my Sambar, I also used .300 WSM brass... but the reason for that is that I have hundreds of .300 WSM brass and zero .325 WSM brass.
 

Forum statistics

Threads
65,468
Messages
1,445,097
Members
136,160
Latest member
FranciscaD
 

 

 

Latest profile posts

Made it to Augusta Georgia yesterday for a meeting, hunt bookings are looking good for 2026 and 2027, had a great time on our Alabama safari shot a rutting deer at 200 yards with 7mm PRC near Huntsville and then headed on to Butler Alabama and semi guided my first deer ever shot a very nice broken off 8 point with hunter there and spend a few days on 1100 acres hunting preserve awesome place!
Ray B wrote on JMJ888's profile.
I am righthanded, so not interested in the rifle, but I have a 375 RUM and 350 gr bullet loading data is very hard to come by. If you could reply with information regarding your loads I would greatly appreciate it. Thank you, Ray Boone, Leavenworth, WA
mcr wrote on gbflyer's profile.
Hello - I was looking at your post from several years ago regarding the Winchester 300 H&H. Any chance you still have the lefty M70 300 H&H for sale?
Thank you, Mike
'68boy wrote on Rare Breed's profile.
Wife and I will attend ah dinner in Nashville Friday night. Jay Sheets and wife Chris
crossfire3006 wrote on Hornedfrogbbq's profile.
An excellent AH member right here! I had a fantastic transaction with Hornedfrogbbq (I was the seller). His communication was first rate, payment was extremely fast, and I would have absolutely no reservations at all dealing with him again. Thank you, F!
 
Top