Home Forums Lever Action Central Lever Actions - General Recent Production Win 94 38-55 Bore Size?

I picked up a Win 94 Legacy in 38-55 and I've started looking into reloading and noticed all the threads on bore diameter variations for this caliber for some reason. Were these variations mostly for the older rifles, or do current production rifles still have this issue? And any idea what my bore should be and what diameter bullets I should be trying?

Good question.

Hopefully someone will answer you.

I have a Marlin Cowboy 38-55 , I bought new in about 1999. It's bore slugs right at .378. Realize it is not a Winchester , but your Legacy comes from about the same time period. I would guess they are the same. I shoot my own home cast bullets sized .378 &they shoot great.

You could remove the bolt, tap a pure lead egg sinker into the muzzle, then with a dowel tap it out again from the chamber end, and carefully measure with a micrometer, though a caliper may work. That would give you the dimension of the lands.

The way I understand it is litigation over the decades has forced uniformity in calibers/ cartridges.

In early days there was monkey business in bore diameter so the firearm was ammo specific. I.E. If U owned a Marlin….u needed Marlin ammo.

The .38-55 (30,000) as originally drawn, in all it's match winning glory was in fact a .38, usually .379 to ,381...many Schoyen and Pope and even Marlin and old Winchester, barrels measure the nominal .38. Then at some point, probably around the early 60's...definitely by 1978 (the ill fated Winchester 'Big Bore' debuted) the pointy heads of the industry decided the .375 Win (50,000) was 'better'. It was better for them, they had tooling for .375 barrels, they had jacketed bullet making tooling, they could boost performance (hah), they could avoid liability by rattling .375 bullets down the old .380 barrels in case somebody screwed up. IMO lawyers, accountants and efficiency experts schidt the bed. Slug your barrel, pull down a modern .38-55 cartridge and I think you will find .375 dimensions. Still, either dimension makes a fine cartridge, just get your dimensions and load from there. Disclaimer, the above is all half baked opinion...Winchester, and SAAMI never bothered to call me...idiots. grin

Slugging the barrel is the only way to be sure.

That said, since your rifle is recent production I'd assume it's made by Miroku. My 1885 High Wall 38-55 is also made by Miroku and the barrel slugs an exact .375" groove diameter. Since the barrels are made by the same Japanese company (folks not known for their sloppy machine work) and likely bored and chambered using the exact same tooling one could deduce that yours is also .375. Not conclusive but a good place to start.

AFAIK all .375 jacketed bullets are going to be .375" so there is no choice there. I used cast bullets sized to .377" to get the best groups in my barrel.

Of course, with cast bullets you want to match the throat diameter, not necessarily the groove diameter - that's why I went with .377", but that's a whole 'nother topic by itself. You could ask about this on the cast bullet forum but be prepared to be led down multiple rabbit holes.



One other caveat or perhaps bit of advice. When I first started looking at reloading the .38-55 it seemed that die sets varied almost as widely as bore dimensions, especially the neck expanders. Unless something's changed in the last few years, calling or emailing the various companies gets no useful info since their customer service folks either don't know or won't tell you the diameter they use. RCBS makes a Cowboy die set with two different expanders, one is .379" and the other is .376". The smaller diameter worked well with the .377" cast bullets and even with the .375" jacketed bullets. Having a single shot I never crimped case mouths but you'll want to do that for your lever rifle.

Below is an article specific to the anomalies associated with the 38-55 WCF. Bullet diameter and groove diameter are discussed. Of more concern in this article is brass length and thickness. It appears thick brass in the past has led to chambering problems. Article is from Starline Brass stipulating two lengths of brass and thinner made brass for the 38-55 WCF. Hope this helps.

Mic McPherson on the 38-55 WCF

Ran into that problem. First the expander plug was to small and was for 375 bullets. .MY 1906 Winchester needs .381. Then it would not expand deep enough and caused a bulge in the case when trying to seat a bullet past the .250 inch it expanded the brass. If everything was not lined up perfectly the bulge ended up on one side of the brass and the round would not chamber.

Having my own lathe, I made a new one. .379" diameter and expands the brass a about a 1/2 " deep.

Then I found out the bigger diameter bullet would not go thru the seating die .That took a trip back to Lee, along with a bullet to get it opened. Luckily there was no charge for that

Wow thanks

FWIW. Track of the Wolf website sells a .397” diameter expanding plug for Lee dies that is long enough to seat bullets properly. About $4.00, have one works great.

All of the above is why, if'n I had to do it again, I'd just get a .375 Winchester and load it down some.

Not dissing the .38-55, it's a good round and can be very accurate, it just requires a definite loony mindset to work with.

Did you mean .379?

They sure do. This one I have, my nephew gave to me. It sat in his closet for a good 30 years and he said he had 1 round for it. The guy that gave it to him had never shot it either. I about crapped when the LGS, that he shipped it to, said it was worth $2200- $2500.

I like to tinker with these old lever guns. I had similar problems with an old Marlin 94 in 38-40.

I bought one of the Winchester Bores 94's Angle Eject in.375 when they first came out. Probably on the mid 80's or so.Shot a few elk with it, but never warmed up to it.

If you have a newer Winchester (post-64) then you can about bet on a .376-7 bore. No need to worry about the larger bored Marlins. Been there done that at least a dozen times.

Yes .379 inch diameter.

Mine built in 2005 slugs .379". Winchester factory ammo with .377" jacketed bullets shoots very well but slow. Handloads with .375" jacketed bullets go through the target at 25 yards sideways. Have some Barnes .377" jacketed to try.

Use as large of a bullet that will seat in a case and chamber in your rifle. Starline brass has an article specifically about the 38-55 and their 2 different length brass which could be worth a read.
Good Luck,
Rick

Check out Vollmer Bullets. (vollmerbullets.com) He makes 38-55 jacketed soft point bullets in diameters from .375" to .380" by .001" increments. They are wonderful for old rifles with a worn bore.

I have a Legendary Frontiersman 38-55, shoot 265gr hard cast gas check bullets sized to .380 at 1855 fps over RL-7, unreal accuracy for the platform and absolutely no leading.