I was wondering how strong the new 38-55 was if it could handle 375 winchester loads or is it just strong enough for factory loads.I also saw an article where they are using 38-55 brass in 375 winchester big bore because the 38-55 hold 4 more grains of powder than the 375 win.I have two big bore 94s in 375 win and the brass is getting hard to find.

Don't do it, the 38-55 has a lot lower pressures than the 375, different powders are used. Not unless you like blowing up recievers. The 38-55 and 375 are almost the same case. The case is thicker on the 375, and remeber The powders used are way different. Les

As Violator said - NO! You may be able to chamber
a 375 Winchester round due to chamber tolerances, and you would then be igniting a much more powerful round than the 38-55. You may even think
you got away with it until you find that your receiver has stretched and you have excess headspace. You may even think you are getting away with it until something lets loose and the gun is destroyed or you are injured. I do not know why Winchester didn't make the 375 case longer than the 38-55. I wish they had.

Use the 38-55 as is - it is a great cartridge for hunting and fun shooting.

The 38-55's I have seen have the standard sides on the receiver. The .375 has thickened sides at the rear where the locking part slides. The reason for this change was reportedly the .375 stretched the original frame and had to beefed up.

A lot of people use 38-55 brass in their .375's. If trimmed, it will fit. However, it holds more powder because there is less brass it it. It would probably not last nrearly as long as .375 brass with full power loads.

BTW, I have a 94BB in .375 Win. They make brass for it once a year. Check with the catalog house when that is and order a lot. Thats what I did.

YOu might get away with it in Marlin but the Winchester was a special receiver. The bullet diameters are different too. 378 for the 38=55. That might give you some pressure problems too.