Patching a 9mm to 380

[OverMax]

Just wondering has anyone tried to patch a 9mm 115 gr up to 380? I would think such bullet would be a good self defense thump-er. (litt'l more weight'er than a 95)

[Nobade]

What does the patch do? They are the same diameter to start with. Just load your 380 cases with heavier bullets and see if you can get them to function through your pistol.

[MOA]

This is from a RCBS 115 grain mold. It is listed in the RCBS #1 reloading manual for use in both the 380 auto and the 9mm. I load it in both.

https://i.postimg.cc/XqMXYgXB/20220513-175730.jpg (https://postimg.cc/xJR9sMv9)


For those of you out there who have never seen the RCBS reloading manual this is what it looks like. It goes back a few years, so with all the changes in powders a work-up is important.

https://i.postimg.cc/rpyL1Tzf/20201227_135306(1).jpg (https://postimg.cc/XrPh***5)

[skeettx]

Soooo you want to go from .3555 to .380 for the 38-55 cartridge?

Should be no problems except getting the paper to stay on the bullet because
of the short shank.
And the twist rate may cause the bullet to tumble.

Mike

[DougGuy]

You will run right into your user name attempting to get a 115gr to work in a 380 SUCCESSFULLY. If it could be done safely, the industry would have been making those for decades.

[MostlyLeverGuns]

A .380 Auto or .380 ACP is another name for the 9mm Corto or 9mm Kurz, 9x17, 9mm Short. It is has a 'nominal' .355 diameter bullet like the 9mm Luger or Parabellum. Some 38-55 rifles use a .380 diameter bullet but the .380 ACP uses .355/.356/.357. I have used the Lee 358-105-SWC with great success in the .380 ACP. Heavier bullets MAY work with careful load development, but you are a REALLY slowing velocities with heavier bullets.

[kerplode]

Like Doug said, if 115gr bullets worked well in 380ACP, you'd be able to buy them as factory loads.

The simple fact of the matter is that the 380ACP doesn't have enough powder capacity or working pressure available (SAMMI Max of 21500psi vs 35000psi for 9mm) to drive a 115gr bullet to a useful velocity. Trying to do so is asking for problems.

If you want a 9mm, buy a 9mm. There are lots of choices that are not much bigger than a 380.

Buffalo Bore also makes a 100gr +p hard cast flat-nose (https://www.buffalobore.com/index.php?l=product_detail&p=127) that is a potent load. Recoil is harsh out of something the size of an LCP, though. It's also kind of hard on the guns in my experience, so its a "load in carry mags but shoot infrequently" sort of a deal.

And yes, they're both 0.355, so patching is unnecessary...

[Kosh75287]

There WAS data in the 1971 Lyman reloading manual for 115s in .380. That page is the only one missing from my copy of the manual. Velocities WERE low, but not unworkable. They would be ideal for a suppressed firearm.

[kerplode]

There is still data for 115gr bullets in the 380ACP in the Lyman 50th, but velocities with MAX loads are in the high 800fps to low 900fps range from a 3.75" test barrel. Actual velocities in something like an LCP would probably be low 800's. I'd be surprised if a 115gr JHP designed for 1100fps would even expand at all at that velocity. If it did, it wouldn't penetrate much.

380 is always going to be a compromise. It just doesn't have the juice to do what a 9x19mm can.

[GregLaROCHE]

Have you considered powder coating them to gain a little more diameter?

[MOA]

Velocities shown in fund's manual.

700x and Bullseye get you close to 900 fps in the testing. I think the testing used a 4" Browning pistol. My biggest challenge was a overall length fitting in the magazine. A number of adjustments was required.

https://i.postimg.cc/nzrvyXSN/20201227-165243.jpg (https://postimg.cc/G808YmCj)

https://i.postimg.cc/52b4cwfW/20190506_112716.jpg (https://[url=https://postimg.cc/GHgwGTBX)

https://i.postimg.cc/5NZ4sZRy/20190506_110727.jpg (https://postimg.cc/sv4CX0yC)

[barnetmill]

You will run right into your user name attempting to get a 115gr to work in a 380 SUCCESSFULLY. If it could be done safely, the industry would have been making those for decades.

Many years ago I got truncated 9mm style luger 125 grain bullets to work in a 380 mauser Hsc with just enough power to function the slide. In other 380s they would not work in the magazine. Not saying it is a good idea and I would not do it in a keltec for example. I inadvertently fired them in an Astra 600 and other then very badly swollen cases, function was perfect and recoil was mild. The A600 is a blow back 9x19 gun designed for sale to Nazi Germany.

[Rapier]

I carry a 380 pocket gun only as backup, totally done up for 100% function. I carry Corbon 90gr JHPs, 1050fps the ballistics gel tests show 15” penetration and expansion to .5 inch. This is a cast forum, but… The 380 really needs as much help as it can get in accuracy, velocity, expansion and penetration. Practice and shoot it as much as you can. Cause a backup means a backup, it is all you got when you need it.