38-55 VS 375 Win...????

[rbertalotto]

I recently bought a couple of rifles in 38-55. A Lyman Mini Sharps and a Winchester 94.
I also have in my collection a 14" Thompson Contender barrel in 375 Winchester

So I looked in a reloading book and I see that the two cases are nearly identical. And sure enough, in all three firearms, both cartridges fit with no issues.

Very strange that the 375 is a bit shorter than the 38-55. This allows a 375 case, at upwards of 52,000CUP to fit and fire in a 38-55 with a limit of 28,000CUP. I would have thought Winchester would have made the 375 longer so this couldn't accidentally happen. Especially in older, Black Powder, guns...........

I measured five cases of each:

The 375Win average 146.6g and the 38-55 cases average 136.0g in weight
The 375 length average 2.006" and the 38-55 average 2.075"
Just above the rim, both cartridges are .414 and at the mouth, both cartridges are.390 (new, unfired brass)

I would imagine it is totally safe to fire 38-55 cartridges in my TC 375Win barrel...........(but certainly not the other way around)

http://images18.fotki.com/v438/photos/2/36012/11139570/P1030488-vi.jpg

http://images43.fotki.com/v680/photos/2/36012/11139570/P1030490-vi.jpg


Anyone have any experience with this?

[Bullshop]

Sounds like you have it figured out.
One thing I might mention is that trying to use the shorter brass in the longer chamber with soft boolits drove me nuts with erratic accuracy.
Fit the brass length to the chamber length and all is well.
I now buy the extra long 38/55 brass from Starline and fit them to the chamber.

[fryboy]

there's minute differences in neck diameter as well as perhaps bore size , the 375 seems to run closer to 375 while the 38-55 tends to be a wild card , also of note fitting and safe firing are two different entities and something to strongly consider , the 375 brass is heavier/thicker and all my test agree with this , while the stronger case helps for the pressures encountered with the 375 perhaps the lower pressure of the 38-55 mite be why more folks have an easier time with it and cast boolits ?

[Rocky Raab]

Yup, original .38-55s used bullets as large as .380", although most ran .378" or so. The pure wild-assed guess is that when Winchester designed the .375 Win, they assumed that a) only jacketed bullets would be used in the .375 and b) those .375" bullets would release enough pressure to keep a .38-55 gun from performing "spontaneous omnidirectional disassembly" if a .375 round were fired in it.

But still - making the high-pressure round short enough to chamber in a low-pressure gun was dumb, dumb, dumb.

[jgt]

If you read Paco Kelly's articles on the .375 you will see he fire forms the 38-55 in his .375; then takes advantage of the length and thinner walls to get more powder in the case to shoot in his .375.

[rbertalotto]

Winchester could have easily put a small "belt" on the 375 to stop it from being used in a 38-55. But it would still feed in a lever action quite easily.

Or a larger rim would have worked fine also.

[Mk42gunner]

Two things Winchester was probably banking on when they brought out the .375:

1. The .38-55 was pretty much a dead cartridge in the late 1970's, and

2. The warnings that used to be repeated continuously of only using cartridges in guns that were marked for them.

Although I don't really see how #2 could fly what with the way the .30 WCF and .30-30 are marketed.

Robert

[MtGun44]

I always wondered exactly the same thing. Seems like a pretty dumb thing for a
gun/ammo maker to do.

Bill

[Jim]

A .308 or 8MM will chamber in a .270. Figure that out.

[HangFireW8]

20 gauge in a 12 gauge shotgun. Great fun, that one. Not only will it chamber, you can chamber another 12 gauge behind it!

HF

[stubshaft]

The difference can be found in the web of the case the .375 Win has a thicker web because it was designed to operate at higher pressures.

[alamogunr]

Can .38-55 factory loads be fired in a Big Bore? I have a box of .38-55 w/255gr that I picked up at a gun show several years ago on a whim. I just went out to the shop and measured (as best I could) the diameter of both .375 Win 200gr and the .38-55 255gr loads. I couldn't find my bullet puller so all I could measure was the bullet just ahead of the case mouth.

The .375 measured .375 exactly and the .38-55 measured .370. This was opposite what I expected. Is it possible the .38-55 bullet is larger inside the neck?

I don't need the .38-55 loads but would like to have the brass.

[Bluehawk]

MOST of the newer 38/55s have actual bores of 375 ( the newer 94s were that way AND some of the Hi Walls and Brownings.)
THE H&Rs were larger bore and MINE runs about 378 . I had an original 1899 Savage in 38/55 that shot the Barnes original Bullet at 377, but NEWER WInchester ammo would not shoot at all ACCURACY WISE! I pulled those bullets and found them to be 375.
Chambers were very odd in the old Specs, and MY Savage would NOT chamber any round with a bullet larger than 377 But the bore was larger at 379 .MOST of the older original ammo was Hollow base and expected to bump up to bore size.
From what I have read the H&Rs went with original specs and some odd things happen with bullet size .
I had accuracy problems with my H&R when I first got it . IT would NOT chamber bullets of 378 or 379 in Winchester Brass either older brass or new Virgin Brass. IT WOULD chamber anything smaller . AGAIN mine would shoot the J bullets of Barnes at 377 with reasonable accuracy . AND would NOT shot with any accuracy with Cast boolits at that size even trying 20/1 Which SHOULD have bumped up a bit . THEN I got some info from someone ( HERE I BELIEVE ) and got some Starline brass It is thinner but I suspect a bit stronger than Win brass It now chambers 379 Cast bullets fine and now the gun Shoots VERY WELL (Using AA 5744 but cant remember the exact load off hand but getting about 1800 FPS OUT OF IT .) I COULD Duplicate 375 loads ( a SLIGHT bit more velocity ) but WHY ? Only shot one deer with it so far and it went less than 20 yards from hit point about the exact same as the deer I shot a few years previous with the Savage and the Barnes Bullets.