Loading 9mm bullets in 357 cases?


April 21, 2007, 05:16 PM
Family legend has it that my grandfather liked to load his 357 brass with 9mm bullets. Because the 9mm is very slightly undersized, he supposedly got amazing velocities. Less barrel friction.

Has anybody here tried such a thing?
Does anybody here know why it might be dangerous, and should not be attempted?
If not, is anyone here aware of published 9mm 357 reloading data?

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April 21, 2007, 05:34 PM
edited: read it wrong. Sorry

April 21, 2007, 05:42 PM
It would not improve velocity, though I suspect it could be done. At .355" accuracy would fall off.

April 21, 2007, 05:48 PM
Yes, he may have liked doing that. Was it safe? Probably. Smart? Possibly not.

I just did a quick advanced search with "9mm" and "357" as the search words and got 18 hits. Not all are relevant to this topic (like 9mm and 357 dies being sold, etc), but there were at least a couple you might want to peruse:


Some Ruger Blackhawks were manufactured to shoot both rounds, but using different cylinders. So the second thread above isn't exactly in line with your question, but does show that the smaller bullet out the 357 barrel will probably have decreased accuracy. Which makes sense. As far as loading the smaller bullet in the 357 shell, well . . . I personally wouldn't do it if I could avoid it. And since I can, I will avoid it.

April 21, 2007, 06:09 PM
I believe CorBon uses a 110 grain 9mm DPX bullet for one of their .38 Special +p loadings.

April 21, 2007, 06:18 PM
9mm and 357 mag/38spl are not the same diameter, 9mm is smaller, not really an accuracy enhancer.

M2 Carbine
April 21, 2007, 06:57 PM
I've loaded 9mm bullets in 38/357 and 38 bullets in 9mm and both in 9x18 Makarov.

Bottom line, it's not worth the trouble.

April 21, 2007, 07:07 PM
I had a friend that liked to load Speer's 9mm 147 grain Gold Dot in 38 Special cases for his 3" Model 10. He got groups on par with factory ammo. A couple of thousandths undersized doesn't matter as much with jacket bullets as it does with lead. If you want to try, go ahead. You can't really hurt anything just by using the 9mm bullet.


April 21, 2007, 07:07 PM

** Includes two cylinders, one chambered in .357 Mag. and one chambered in 9mm Parabellum, which can be interchanged without the use of tools.

April 21, 2007, 08:13 PM
I've loading 9mm lead bullets in .38 Spl. cases with a standard-pressure load of W-W 231 powder. It worked OK, decent accuracy for indoor shooting.

I can't really recommend it, though. I only did it because my 9mm Hi-Power didn't like the lead bullets and I was stuck with 1K of them.

April 21, 2007, 10:00 PM
I used to own some Colt Python's they slugged out at .356 if I recall while my Smith & Wessons were .357.
I was shooting Cast lead bullets sized .357/.358 the Smith Shot them well.
The Colt would lead up early.
If you have a slightly undersize barrel the 9MM may work fine.

April 21, 2007, 10:29 PM
Starter52 Quote>"I've loading 9mm lead bullets in .38 Spl. cases with a standard-pressure load of W-W 231 powder. It worked OK, decent accuracy for indoor shooting."

Some years back, cast bullets were hard to find for a while in my area. I prefer 158 gr bullets but had a lot of 9MM 125 gr RN cast bullets on hand so tried them in .38Sp and light .357 loads. Like Starter said, at short indoor range distances they worked fairly well but at longer distances not so good. I think jacketed 9MM bullets would be safe enough but you would probably lose velocity rather than gain and accuracy would suffer too.


April 23, 2007, 10:27 AM
Use to do it quite a bit in the 60s for .357 when we wanted a light bullet traveling at fast speed. These were pre-Super Vel days and when ammo in .357 was usually found in 158 gr only. I won't give the loading here as it's not in any loading book. We'd often use .380 bullets in 88 gr loaded in .357 cases fired out of a pair of 6" S&W Mod 28. They were great on groundhogs, muskrats, coyotes, and foxes.
The reason your grandfather got the amazing velocities wasn't due to the slightly undersized 9mm bullets but because the 9mm bullets were so much lighter than what was available for .357.

Jim Watson
April 23, 2007, 10:37 AM
Lee Jurras/Super Vel used light, undersized bullets to get the high velocity that changed the pistol ammo business.

If you want to shoot 9mms in .38 revolvers, you must be sure your sizing/expanding dies give a snug fit on the smaller diameter bullets. Ed Harris did an American Rifleman article on the subject and found that he had to have RCBS make him an extra small sizing die to be sure of that. He also found that driving 9mm hollowpoints through a .357 revolver at magnum load levels was not accurate and could even break up the bullets.

April 23, 2007, 01:01 PM
If your goal is "amazing velocity", get yourself some 125 grain .358's and load them at the TOP of the powder levels--I like 2400. If your handloading already, you can load these lighter bullets crazy fast!! That's assuming you have a strong enough .357 mag pistol, and a 6" or longer barrel helps velocity a little too. Using bullets under sized is not good for accuracy.

April 23, 2007, 01:27 PM
I accidentally loaded a batch of .38 Special cases with 9mm bullets when they shipped the wrong bullets. Never tested them for accuracy but they plinked just fine. I hardly think that .002" is a big deal one way or the other.

April 23, 2007, 01:42 PM
Thanks for the replies everybody!

April 23, 2007, 02:19 PM
I just recently bought 1000 lead 135 gr. 9mm bullets for $30. I have used them in my Blackhawk Convertible in both the 9mm and .38 Special configuration. They worked ok, but I was using a medium target load at bottles at 15-25 yards. I just made sure that I placed a firm crimp on them in the 38 cases. Depending on the bullet type, the base will sometimes flare to prevent gas blowby which reduces the chances of the bullets leading your barrel.

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