Have my eye on a ruger 3840 and after some research I find that -in the ruger - it can be loaded up to 10mm plus velocities. Any experience out there ??

I shoot the .38-40 in an original Win. 1892 rifle, which is very strong.
Relatively late in the cartridge's production they did have "Winchester High Velocity" smokeless loads intended for use in STRONG rifles only, and no Winchester 1873's, Black Powder SAA's, etc.. That said, it's a great cartridge for what it's for, WITH PROPER BULLETS. I have some original 1950's/60's boxed .38-40 bullets
by Winchester that were sold as reloading components. They have lots of dead-soft lead exposed at the nose, and tin-foil thin jackets to assist in expansion. That should tell you something.

That said, the .38-40 is a black powder cartridge, and has VERY thin neck walls, to allow them to expand at black powder pressures, to seal the chamber and prevent fouling from getting back into the action. The tapered design of the cartridge is there for the same reason.

One only makes a small "Oops!" on a .38-40 cartridge once -- they are easily wrecked. Beyond that, any bullet you use will HAVE to have a crimp groove suitable for the .38-40, to prevent bullets "jumping the crimp" under recoil (in a revolver) or pushing back into the case (in a tubular magazine). Given the very thin case walls, I don't know that it would be possible to form a tight enough crimp to fire 5 or 6 high-pressure rounds in a revolver without 1 or several jumping the crimp.

One of the most popular cast bullet moulds for the .38-40, that dates back to black powder days, relies on a case full of BP to prevent the bullet's pushing back into the case in tubular magazines. It's basically unusable with smokeless powder due to instant set-back.
A cannelure tool used under the bullet might prevent that problem, but then the thin cases will likely separate in 1-2 firings.

As to brass, Starline is my clear favorite. I find it significantly better than Winchester, and have no experience with Remington. (I'd expect RP brass to perform like Winchester.)

CAN you, with a very careful study of powder charges and approprate bullets, possibly get it to approach the 10mm? Probably, with case life of about 1 shot each, I'm guessing. Should you? I wouldn't. If it were the only firearm I had, I'd work with it, but respect the very old cartridge design, which is not nearly as thick/hardened as the 10mm.

Would I set out to make a .38-40 match a 10mm on purpose? NO. A spare cylinder in 10mm would be vastly superior, in my opinion.

I hope this helps,
John

Oki, go for it. Here's an article on the .38-40 by John Taffin. His loads sure look like deer killers to me.

http://www.sixguns.com/tests/tt3840.htm

John and Bill, thanks for the feed back. I had read the article Bill provided prior to asking. After noting that the case was a necked down 44-40 and started having doubts. I will have to double check with the gun shop to see if the have the 10mm cylinder but I am betting they don't considering the asking price. Still, not a 41 mag. Think I will keeping looking for a 41.

I use one of the Linebaugh custom revolvers with an oversize cylinder, however, if you can get some 200 grain LFN bullets, these work well on deer.

The Starlne brass appears to be very good. I shoot some Winchester brand as well. Necking down the 44-40 does not get you any increase in neck thickness which is a weak spot. Just slow down and be careful when reloading and you should have no problems.

My pleasure! All the talk of having to neck down
.44-40 brass shouldn't scare you off. Factory .38-40 brass is readily available from Starline. I suspect the article may have been written before .38-40 brass became plentiful. Note the reference to WW452AA, which has been out of production for many years.

Too bad, because it was a great powder, beloved in the 1980's for IPSC. It gave noticeably mild recoil in .45 ACP, metered well and was cheaper than other powders. Yes, the .38-40 will kill deer with good shot placement, it's just not as easy to work with as a modern cartridge. Not terrible, just pay careful attention when handloading. If they have the 10mm cylinder, sounds like you found a good bargain! If it's real cheap, don't let the .38-40 scare you away. It is a good cartridge!

Hope this helps,
John

I will also recommend you get Redding dies to reload with. They do not swage the shoulder back down, thus not working the brass so much. That and a bullet with a crimp groove will work wonders in that cartridge.

Was just re-reading "Sixguns" by Elmer Keith. He was killing elk almost a century ago with a Colt in .38-40 and 260-grain bullets for the .40-82!

I have shot the 38 WCF in a Linebaugh and in a Buckeye since 2007.

The 38 WCF will outpace the 41 mag by a substantial margin in strong guns by the experienced and cautious handloader.

My original go-to load is a 200 grain at 1750 fps in a 6.5" barrel. Now I shoot 230's at 1550.

PM me for a complete list.

Todd

Here is your answer; I shoot 38-40 in two revolvers and a 92 rifle in CAS. I use only Starline 44-40 brass; easier to get and cheaper, and it is stronger. You don't even know you are necking anything down it is already so close. Remember, you are only going from 43 to 40. In a Ruger, load it up and hunt with it.

There are 5 shot 38-40s that are capable of some amazing things. You will have to rethink what is possible if you get experience with one from Linebaugh, Harton, etc. You can drive Hornady 180 XTPs at some interesting velocities. You have to change the canellure to crimp them further out and use stout brass like Starline, but it's a lot of fun.