Hey gang,

I have heard some conflicting reports on using .38-55 ammo in a .375 Winchester. The rifle is a Model 94. Anyone know the deal on this? I know of a local gun store that is getting a shipment of .38-55 ammo. It would be great if I could shoot this ammo in my .375 Winchester.

From what I heard it should be okay. The 38-55 was the parent case for the 375Win and is 0.005" longer. The 38-55 uses 0.377" projectiles while the 375Win is 0.375" which is really no significant practical difference. Might be worth trying some factory rounds to see that the extra lengh and bigger bullet don't cause any tightness issues.

Years ago when I first moved to Western Australia they had extra stupid gun laws. The 38-55 was classed as a "low power" firearm and was automatically covered for hunting when applied for a target shooting licence. The 375Win was classed as a "high power" and could be obtained under a target licence but needed additional support (letters from property owners) to get it included under a hunting licence. To get around this bullcrap, many shooters bought a 375Win and had the chamber reamed out the extra 0.005" and relabelled as a 38-55. They could use both 38-55 and 375Win ammo through them, so the 0.375" bore did not cause issues with the 0.377" bullet of the lower pressure 38-55, but 2" isn't a huge difference anyway. (I've used 0.312" projectiles in 0.308" without issues cf the proper 0.308" projectiles.)

My 94 375W will feed loads with the 2.080" 38-55 brass just fine, not sure about the longer 2.125" stuff, but I would guess probably not.

It actually shoots .378 cast a lot better than .376 or .377. I haven't tried anything over .375 jacketed in it.

.378" 245gr RNFP in 375W brass over 10.5gr Unique from 50yds.

This is what Buffalo Bore ammunition has on their website concerning the .38-55 ammo they load.

"OUR 38-55 WORKS IN ALL WINCHESTER 375 RIFLES

Our 38-55 ammo is also designed to work in ALL 375 Winchester chambered rifles. ALL means ALL. Winchester, Savage, and Marlin all chambered rifles in 375 Winchester. All 375 Winchester rifles utilize chambers long enough to accept the 2.085-inch 38-55 brass, even though 375 Winchester brass is only 2.020 inches long."

Wilkeshunter,
I have one of the first 10k made and you should be good to go….
Make a dumby round w/ 38-55 short brass and seat a 220 ~255 gr bullet shallow, approximately 0.100” from cannelure… OAL will be about 2.677” … Slide in chamber and check function. Adjust seating if needed but from my experience with the Win. 94 BB, you will know know pretty much what you are wondering…

Feel free to private message me if you need any assistance…

From what I’ve read or at least recall the 94 Winchester will chamber and fire the 38-55 fine. I have not tried it in mine. I used fire formed 30-30 brass for cast loads and 375 brass for jacketed full power loads.

To All Following,
If you have completed the task from previous post and in need of further clarification.
Measure your chamber. Order from Brownells, a Sinclair Chamber Length Gage Insert. *375 Caliber Chamber Length Gage. I used 38-55 short brass from Starline… *Follow the simple instructions provided in said insert.
The chamber from the factory on the subject Winchester 94 BB 375win. measured 2.125 in.
2.125in is the length of 38-55 Long Brass from Starline.
Understand basic reloading techniques, shorter brass (375win) packed with powder (C) will have the higher range of chamber pressure more than the 38-55 longer…
Tim @ Buffalo Bore did all the work for you using his Winchester 94…
Go burn some powder!

There's helpful YT videos for those wanting to form 30-30 brass to something useful if you have it laying around.