338-300 Win Mag

jmr40

New member
If I understand the OP right part of the motivation is to get increased performance, with readily available brass. 300 WM is certainly one of the more readily available magnum cases. Much more so than 8mm, which might be better performance wise.

I dabbled with 338-06 for a while. I chose it for the same reasons, brass is easily made from 30-06 brass and I just liked it better than 35 Whelen.
 

old roper

New member
thesheepdog, I've had 2 300WSM, 2 300 mags build also couple 300Wby beside the 30x338mag. I have fair amount of reloading data for all and it's all in how you have them build. I gave my nephew 300WSM and 300mag so still in the family. Like you my rifles are not open to a debate.
 

NWCP

New member
I've thought about a 338-06 lately, but I already have a .338 WinMag and can't get myself to pull the trigger on the 338-06. It has less recoil than my WinMag, but the WinMag has a lot more horse power and is easy to find when away from home and I run out of shells. It can also be loaded down for medium sized game, or bumped up for dangerous game. Don't see much 338-06 on the shelf in podunk Montana, or anywhere West Texas.

A 338-300 WM sounds neat, but why it over a 300 WM, or a .338 WinMag for that matter? Just curious.
 

jmr40

New member
A 338-300 WM sounds neat, but why it over a 300 WM, or a .338 WinMag for that matter? Just curious.

I asked the question earlier, his reply in post #8

The 338 WM has a shorter case than the 300 WM. This equates to nearly 10gr difference in powder capacity. By using the 300 WM brass over the 338 WM Brass, I'm able to push the bullets a little faster.
 

taylorce1

New member
If you want more performance over a .338 WM and readily available brass do a .338 Campfire. It's also known as a .338-375 Ruger. The Ruger case has nearly 100 grains of H2O capacity and that puts you in .340 Weatherby territory and only 13 grains behind the .338 RUM.

I know if I was going to do a magnum wildcat I'd get rid of the belt on the case.
 

GeauxTide

New member
10 grain increase?

Looking at Nosler 6, a 300WM 200gr Partition lists 71.0gr of IMR 4831 as max. The 338WM with a 250gr Partition (same SD) list 69.0gr of the same powder as max.
 

reynolds357

New member
The .300 Win mag necked up to .338 used to be a quite common wildcat. I always preferred the .340 WBY to it, so I never built one.
 
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