375 Winchester Brass. . .where the heck is it???

[Randy Bohannon]

I just received 250 pieces of Starline 38-55 to try in my B.B. 94 hopefully I don’t need to trim a lot just square the case mouth , chamfer and anneal.

[Chill Wills]

Randy, you ordered the 2.080" short length? I am assuming?

[Randy Bohannon]

Yes the short brass 2.080”

[Chill Wills]

It is interesting that the SAAMI print for the 375 Winchester shows 2.080" for the chamber to the case mouth and the same print shows the ammo drawing calls out 2.020" for the cartridge case length! An intentional miss-match that must have been an acceptable trade-off of manufacturing.
I did not know this way back when. Those advocating for the longer case have a good point! As most of you know, the original 38-55, as produced by Ballard and Marlin call for 2.125"
Starline makes both the original length 2.125" 38-55 and the "too short" version of the 35-55 that has been produced the last few decades by Remington and Winchester, looks like the better choice for the 375Winchester.

There is a difference in case weight in my brass. I have not sectioned one but, I bet that extra weight that is in the 375 Winchester case, is in the head and webb area. Just a guess.

Always learning.

[j4570]

I have a Marlin 375 and a Contender in 14” and 21”. Never used anything but Winchester 375 Brass as I got them when it was available.

I’ll have to get some long 38-55 and see someday.

[TomAM]

MGM Thompson barrels are true 375 Win chambered.

I've never measured 375 Wins by Thompson-Center, Ruger #3, or Savage 99.

I've measured many Marlins and Winchesters, and all freely accepted the 2.125 brass except for one '94 which required a few thousandths trimmed. Cast boolit accuracy is substantially improved with the right brass length.

It's not like shooting 38 spl in a 357 mag chamber. The high pressure in the rifle causes much more boolit deformation as it passes through that big .4" diameter gap, and the .378 groove diameter is way wrong for .375 bullets.

[farmbif]

when I first got my winchester 375 win I used starline short 38-55 brass found it loaded best using 375 win dies it works but the wall thickness at neck is thinner than true 375 win brass. then when. I got the marlin 375 win ive only used true 375 win brass in it. both have barrels that measure exactly at.375.
where is op located? I still have boxes of genuine winchester 375 win 200 grain ammo

[26Charlie]

The Ruger #3 single shot will also accept the longer brass. And, as DanLee says, make it out of .30-30 as we did when the caliber was new. 6 gr. pistol powder, cornmeal on top to fill, a dab of wax or grease on top to hold it in, step outside to fire it up in the air, et voila!

[Randy Bohannon]

I have plenty of 375 Win. brass and have had significant leading at the end of the chamber with .379” cast bullets. I will be ordering a big lube mould from Tom and the longer 38-55 brass and start eliminating the leading. I have always used 38-55 reloading data and IMR4759 powder.