What are the differences between these two? I've read that the Whelen-Brown has a greater capacity by a couple grains.

Would a 338-06 AI chamber clean up to a 375 Whelen-Brown following a rebore?

The shoulder on the Brown is moved forward I believe. Look at the 380 Howell or 380 Hawk

Unless you use an action that will allow your length beyond an 06 you see very little NET powder gain. Even a 260 bullet goes pretty deep

PO Ackley outlines the necessary extra work in his Vol. 1. Headspace may be an issue.

The 375-06 AIMP is the way to go with new 06 cases annealed. An almost perfect rig for Alaska,
other than the 338 AIMP
or the 338 HGT with the 270 IMP case for a tad more
powder space. Or even a 35 Whelen IMP with 300 gr bullets.
General purpose: 338 Imp is the way to go ir the stock 338-06. Beats the 338 Federal, a bad idea with the 308 case-IMHO. Depends on its intended purpose. AK? 375 for sure in the alders...

THE BROWN WHELEN gets you the most velocity hands down but at a price. Its just a lot of work reforming the cases and fireforming was my complaint..The 375/06 Ackley was nice but I settled on the 375x62, necking up the 9.3x62..

Today Id go with the 375 Ruger and it works fine in a standard 98 Mauser and even beats the Holland and Holland somewhat in velocity..

The 375-06 IMP in a standard action works for a lighter rifle.
In 375 -I use a pre-64 M-70 in 375 H&H. I have boxes of ammunition, and some of it is the old Barnes 350 gr RN. An excellent bullet for Alaska, along with the 300 gr Nosler partition or Swift.
With heavy bullets at higher velocity, the weight of the Model 70 really helps. The 375 H%H has been
with us reliably for 114 years. It works.

The Brown will give you more velocity but as stated above it’s a flaming PITA to make.

On the 06 case the 338-06 AI and the 9.3x62 are far superior performers.


Now if you just HAVE to get your cartridge geek on (and some of us do) and you love hard to make stuff then the BW is your huckleberry

I have a 375 Hawk/Scoville. A little more than an Ackley, a whisker less than the Brown.
I throated mine out a little, so I could use the full magazine length. I use a tapered expander, to neck 35 whelen brass to .400, then set the headspace with the sizing die.
The original data for the 375 H/S only takes it to original 06 pressures of 48,000 cup. Careful loading will increase velocities.