I have been reloading 9mm rounds all week and it dawned on me that this in is really a .38 caliber round. I am sure everyone else has had this epiphany, I'm a bit slow. Yesterday, I started to reload for the .38 special with a RNFP cast bullet at 158gr weight with a diameter of .358. Sitting next to the box of .38s was a box of 9mm cast bullets with a diameter of .356 with a weight of 100gr. Is it possible to craft a load so that these 9mm cast bullets will fit the case of the 38spl and fired in a 6" barrel. Is the delta of diameter too big and the weight too light and I assume that would be "blow by". Your thoughts!

Try it and see. You would probably have to taper crimp the 9mm round. You might get some leading. It will most likely work, but possibly not well.

I've done it with a heavier bullet, leads like crazy if they aren't coated (I haven't tried coated so they might too) and not particularly accurate. But they work in a pinch.

If you want to share bullets, buy .358 and then you can size them down to whatever you want for 9mm. I've shot .358 lead bullets in 9mm and they worked much better than the .356 did in the .38. Or use a Lee push-through sizing die to take them down. I like .357 in 9mm lead bullets.

Where the problem lies is the 38 special loading dies are manufactured to utilize bullets .357/.358 ... if you use a bullet sized . 356 , the case doesn't want to hold the bullet tightly and the 9mm luger bullet has no crimp groove .
If you want to load .356 bullets in 38 special cases :
1.) Use your 9mm luger sizing die to size down the 38 special case , not all of the case but the length of the bullet and an additional 3/16" or 1/8" ... this is so the case will grip the bullet .
2.) After seating the bullet then use the crimping die from your 9 mm luger set , to apply a Taper Crimp on the bullet .

If you seat and taper crimp in two seperate steps and apply a taper crimp with TC die from 9mm Luger set ...it should hold the bullet securely ... press on the bullet to test and as you shoot watch the unfired rounds for bullet "creep" ...bullets will pull out of the case under recoil if not properly crimped and held by the case .

What I do is reload my 9mm with .357" cast lead 9mm bullets and also use them in 38 special with a taper crimp but no extra case sizing is required .

Gary

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I've not loaded cast bullets, but jacketed 9mm measure 0.355" and .38Spl/.357 are 0.357" .355 is loose enough in a .38 case that you can easily push it in with finger pressure. I imagine .356 would be substantially tighter, but crimping would still be very desirable to prevent setback. Does a cast bullet, for those who load them, have enough "give" that you can roll crimp into the lead with no cannelure? A roll crimp would be more secure, although a taper crimp might work.

110 grain is the lightest bullet I have load data for in .38 Spl., but you could probably use the lowest powder weight and back off a couple of tenths to start.

I cast all my own, and have separate molds for 38 and 9. No problems.

On occasion i have bought store-bought bullets and once I got undersized .356 38's. The vendor replaced them and said keep them. I tried a few and ended up melting them down and making my own. They didn't work very well.

I have tried the standard 9mm fmj bullets in my 38 special revolvers, twice.

I could not remember the first time results, that was many years ago
but two years ago I did remember that the accuracy was not what I wanted.
I also had some coated 9mm 125 gr. in .356, .357 & .358 Dia. sent to me.
The large .358 bullet would not fit in my chamber of my C9 pistol.
However, I did use them in my 38 special cases, to clean out maximum Lead loads
and also 2-3 rounds after a heavy FMJ work out, to maybe clean the copper out of the barrel.

It can be done but I passed on this idea.

I often use a 146 grain 9mm design sized to .358" in my 9mm, 38, and mid-range 357 loads.

The key is to size them to .358" for the three calibers and then as there is no crimp grove, to roll crimp just over the start of the ogive when used in the revolver cases and to taper crimp when used in the 9mm cases.

Maximum loads in the 9mm and the 38 Special as well as 1,000 fps loads in the 357 are accurate and give no leading with a moderately hard alloy and a good lubricant.

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I have used 147 gr. Truncated cone lead bullets that I cast in my .38 spl. for a long time. Usually in my lever guns for SASS shoots. They function really well because of the taper in the lever guns.

Also , I don't size them , use straight out of the mold and get very good accuracy with my 4 gr. of Unique loads.

Randy

The first .38 Special loads I made used lead
truncated cone 125 grain 9mm bullets. The local gun store had
some on the shelf. No .38 bullets at the time.

They looked odd but shot well from a Ruger Blackhawk with a six and a half inch barrel. I used Bullseye powder and CCI primers.
Used up all the TC bullets the dealer had. Then switched to
158 grain LSWC bullets over Unique. Still shooting similar
bullets and similar loads.

How many grains of Bullseye? Be Safe,

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