My buddy Steve has talked about the 400 Whelen, however the lack of shoulder to keep the brass from the barrel has kept him from building one. Don't know that he thought about a 375 Whelen, will give him a heads up!He does shot the 35 Whelen and loves it for Moose!
Boyd Brooks
If your buddy Steve still wants a 400 Whelen it's no problem with the shoulder.
Just start with the 35 Whelen AI, neck it up to 40 cal, SEAT a 40 cal bullet nose first into the case with an appropriate charge of fast burning powder.
The case must have the bullet in contact with the lands. When fire formed he will have more than enough shoulder.
Personally I have the 35 Whelen AI
The 22K Hornet and my personal favorite 25 cal made using ideas from, the Epps improved, 30/40 Krag improved and the idea of moving the shoulder from the Newton line of cartridges.
The final product is the 25/303 Epps Newton improved. The shoulder of the case is moved forward to give me a .257 length neck, 35 degree shoulder angle and blown out to minimal taper. Moving the shoulder forward and blowing out the case dramatically increased the case capacity.
This sounds like a lot of work but is in fact very easy to do. Three quarters neck size a 303 British case to 25 cal, load a cheap 100 grain projectile using the minimum load for that projectile in the 257 Roberts. Fired case is perfectly formed. On an SMLE No4 action it will beat the Roberts and go close to the 25 ought six. In the M17's or P14s it exceeds the 25/06 and even gives the 257 weatherby a shake up.
I do love wild cats let's see what other can come up with.
The 6.5 credemore is nothing more than a 250 savage AI with a different shoulder angle.
The 9.3/ 300 wsm was done by John Barsness and Charlie Disk and called the believe it or not the 9.3BS.
Cheers mate
Bob Nelson