How close is 38/40 and .38 Special

I was reading today that the original .38/40 cartridge (and I realize that it is actually a .40 caliber bullet) had a velocity of right at 1300 FPS with a 180 gr lead bullet from a 24” barrel, and about 900 FPS from a 7 1/2” barrel, and it got me thinking just how close a .38 Special could be to the .38/40.

I realize that I’m comparing two completely different things here, a black powder 38/40 to a smokeless .38 Special, but I believe that with the right powder and bullet, you could achieve close to 1300 FPS from a 180 gr cast .38 Special in a 24” .357 magnum lever action, and fairly close revolver velocities using the same length barrels.

I know this can be done with a .357 magnum case, but I’m thinking that with a good dose of 2400, IMR-4227, or H110 that this could definitely be done at +P pressure, and possibly at standard 38 Special pressure. What do you guys think? Is this doable?

Armorer 101 said:

If you will buy yourself a reloading manual or six, you might be able to look such data up yourself. Reloading books are similar to cook books, they never go bad, you just use common sense, like using the starting loads to start, not max loads to start when changing lot numbers and that includes powders made in 1950 VS powders made in 2021 with the same name or number as per federal specifications regarding powder and the labeling of powder.
This is all a moot point as they make 357 mag lever and single shot rifles. You do not reload for them like a revolver if you understand reloading at all. Now they (Speer specifically) do make 180gr bullets for the .357 caliber guns, which does include the 38 spl. So you can do a simple comparison of velocities and energy, using a similar firearm. You look it up.

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The problem is that I've never seen 38 special load data for 180 gr cast in any load book. The closest is 173 gr and 195 gr cast in some old load books. Both state 9.5 gr IMR 4227 at pressures well below standard pressure max (around 15,000 CUP) with a seating depth of .380"-.400". That puts the 180 gr cast velocity somewhere around 1,200 fps from a 24" barrel, and around 900 fps from a 7 1/2" barrel with the same powder load at the same seating depth. Since you hardly ever see those barrel lengths, you'd more likely get about 1150 fps from a 20" barrel, and around 850 fps from a 6" barrel. Not exactly .38/40, but close with a little wiggle room.

Rule3 said:

Here is what you can do. I am not saying you SHOULD do it. I do not see the purpose in loading 180 grain bullets in 38 special. But you brought it up.

There has been several "experts" that wrote about coming close to 357 mag loads in 38 special. Use new or once fired brass. Then then "calculated that a 38 special is 10% smaller than a 357 mag.

So use the 357 mag start data for 180 grain bullets and reduce it by 10%, better yet reduce it by 20%!!

On the Hodgdons reloading site. You can see the velocities of the 357 mag with 180 gr bullets from a 10" barrel
AS YOU CAN SEE, EVEN WITH 357 MAG ONLY 3 POWDERS ACHIEVE 1,300 FPS AT MAX LOADS

PROCEED AT YOUR OWN PERIL.!

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I think you may have misread my original post. I’m talking about cast bullets. Hodgdon doesn’t give cast data on their website for a .357 Mag bullet bigger than 158 gr. The only 180 gr bullet they list is a Nosler Partition which is jacketed. Also, the rifle data they do show is for an 18.5” barrel; not a 24” barrel.

You can do a lot with low pressure and slow powder in a long barrel. The question is whether the 17,000 CUP .38 Special or 20,000 CUP +P can breach the distance to the larger volume 14,000 CUP .38/40.

Rule3 said:

It doesn't matter that much if it is a jacketed or lead bullet. It is the same weight. Sometimes Hard cast lead will go a little faster sometime not. Sometimes the jacketed will go faster. Yes, jacketed data can be used for hard lead.

Look at the data for the Nosler in handgun vs rifle it is the same max All I was trying to show was the 10 to 20 % reduction from 357 to 38 special that some folks wrote about.
Why you want to max out a 38 special in a rifle is beyond me? Why not just use 357 mag brass?????????????

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It’s not about maxing anything out, but getting what the round is capable of. 38 Special is a very flexible round especially from a rifle. Hodgdon #25 lists a 200 gr lead bullet at 819 FPS and 170 gr at 859 FPS over 4227 from a revolver; both under 16,000 CUP. That would push out of a rifle at nearly 1100-1200 FPS. I’m sure that H110 or N110 could also be safely loaded at standard pressure that would give even more velocity.

jmorris said:

What rifle?

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Any .38 Special or .357 Magnum lever action rifle; although I only know of one that is .38 Special only, and only a couple that have 24" barrels.

blue32 said:

I bet you would experience the ol sticky extraction before you got there. Now if you tried to match a 40SW to a 38-40, you'd be there in one shot.

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It's possible, but I have run the 200 grain (well 198 gr) bullets using 2400 and Unique out of a Taurus Model 85 before, and they weren't sticky; they also weren't that fast out of a 2" barrel @ about 700 fps. I wouldn't think that any load under 17,000 PSI/CUP would cause sticky brass in either a revolver or a rifle.

GooseGestapo said:

BTW: nobody mentioned that the .38/40wcf is actually a .40cal...

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Very first sentence...

OK, since my original post I’ve had a chance to do some data diving. In my original post I stated that I was comparing apples to oranges (a large case, low pressure black powder .40 caliber 180 gr bullet to a smaller case, higher pressure smokeless .357 caliber 180 gr bullet), but I thought that I could get more or less equivalent results for each in similar size guns (rifle and revolver) using +P and possibly standard pressure load data for .38 special. Since then I have found some interesting tidbits of load data.

RCBS has 38 special data for a 175 RN bullet with H110 powder that should give about 1175 FPS from a 20” barrel, and Lyman 48 has some Titegroup data for a 170 gr SWC that runs 860 FPS from a 4” test barrel. Those I can test in my Henry and Model 19. I realize this isn’t the 180 gr bullets I intended, but they are within 10 gr bullet weight, and should produce standard pressure results fairly equivalent to the original BP 38/40 WCF. No hot-rodding and no guesstimating down-loaded .357. I doubt that there is any single powder to get me there in both cases, but by picking and choosing for the situation, I think I can get pretty darn close.

Now to make up some test loads and give them a try.