9mm And 380 Casting Considerations

[Duckford]

I finally put in an order for a MP5 clone, and am closing in on ordering a PPK/s in 380. Going to round out the collection I always wanted before things, um, deteriorate in the greater global scheme of things.

I see in the Lyman manual they have a listing for a 120 grain round nose cast bullet to be packed in tight in a 380 Auto case, and is listed as a safe reload. I like heavy bullets, and I like casting one weight bullet for caliber at a time during long casting sessions, so this might be up my alley.

Anyone with any insights and experience on heavy weight bullets for 380, or casting with 380 in general? Should I settle on a lighter weight for the 380, and just get the 147 grain Lyman mould for the 9mm?

Will a heavier bullet, at higher muzzle energy, and greater recoil, still damage or wear out the PP family even if it is within SAAMI pressure limits? Am I just being lazy/greedy to get one mold and try to use the same bullet for two calibers?

I'm pretty sure put put loads won't work in the MP5, without using the heavier bullets for caliber. Any other mindful tips in 9mm, which should be the easy consideration?

Thanks in advance.

 

[BB57]

I’ve never shot bullets heavier than 102 grains in a .380 ACP.

90-100 grains is the sweet spot.

With a PP, PPK, or PPK/S you can tell when the load is excessive. Th trigger guard acts not just as a disassembly lever but also as a shock buffer for the slide as the front of the slide comes to rest on the block on the front of the trigger guard. If the load is too stout for the recoil spring, you’ll get a very metallic feel in the pistol under recoil as that block is driven back into the frame.

With normal loads it’s your indicator that the recoil spring is worn out and needs to be replaced. With heavy loads it’s your indicator that the load is too stout for the pistol.

In either case, if you do not install a newer or stronger spring, you’ll batter the frame.

However, a stronger than stock spring isn’t the solution to a heavier load. There’s never a free lunch and even if you install a stronger recoil spring that attenuates the higher recoil, the increased energy stored in that stronger spring is returned when the slide comes back into battery. The slide velocity will be higher and the bolt face, barrel attachment and frame have to absorb that energy. It will accelerate wear on your pistol.

—-

In addition to owning six PP and PPK/S pistols, as well as five FEG PP and PPK clones I also have an MKE made MP5.

I would not consider shooting the same 120 gr bullet in both the PP and MK5 firearms. Stick with a 90-100 gr bullet for the .380 ACP PP series and go with anywhere from 115 to 147 grains in the 9mm MP5.

9mm MP5 wise, the 115 gr bullets give good velocity and good long range performance, and the MP5 is very capable, easily staying in the vital zone on a torso sized target out to 200 yards. 147 gr bullets are nice if you plan to suppress the pistol as they will be subsonic pretty much anywhere warmer than the north or south poles.

——

As an aside, I used to cast a lot of bullets for a number of different cartridges (7mm TCU, .30-30 Win, .30 Carbine, .32 ACP, .32-20, 7.65 Nagant, .30 Luger, .32 ACP, .380 ACP, 9mm Luger, .38 Special, .357 Magnum, .38-55, .45 ACP, .45 Colt, .45 Win Mag, .45-70, .52 (paper cartridge Sharps) and .577 (58 caliber mini balls).

However, I eventually switched to plated bullets and commercial hard cast bullets for all but the really specialized loads (7mm TCU silhouette loads and .45-70 long range loads).

Casting involves more mess and bother than I have time for now. In addition, the logistics of maintaining different alloys for different loads and sizing bullets for different chamber and throat dimensions in different firearms took a lot more time that it was worth.

 

[AlHunt]

I would run different bullets in those 2 different guns. Otherwise, one of both will end up being a compromise.

 

[rockquarry]

I've had good results with the SAECO 122 grain flat nose design in .380; I think some load 125 grain round nose cast. That's as heavy as I'd go in the .380 The case is just too small in capacity for a 147 grain bullet, but such a bullet is fine in the 9mm.

 

[Funflyer]

Just my 2¢, but if I were to use one casting in both 380 and 9mm it would be my 102 round nose or 105SWC Lee. I've developed many good loads for both castings in both calibers but typically only load them in 380.

Another option is with a Lee 120TC mold. Since this one is my favorite in 9mm and functions 100% through all my pistols, I bought another mold, milled it shorter and removed the lube groove to cast a 105 grain TC for 380 use. The design is just as reliable and accurate in my most finicky 380s.

 

[Duckford]

I think I'm going to settle on the 147 grain Lyman for the 9mm and something else for 380. I never intended to try putting a 147 grain bullet in a 380, but I suppose if someone pulled it off they deserve some sort of award.

120 would have been the sweet spot, and a 105 grain bullet for both is the compromise in the wrong direction. I've always preferred mid to heavy weight for caliber, and that's just too light for 9mm use.

Never did get good with the Lee molds, and prefer steel/iron. I'll be looking for a while yet before I make an expensive decision.

Thanks for the replies.

 

[STORMINORMAN]

Just my 2¢, but if I were to use one casting in both 380 and 9mm it would be my 102 round nose or 105SWC Lee. I've developed many good loads for both castings in both calibers but typically only load them in 380.

Another option is with a Lee 120TC mold. Since this one is my favorite in 9mm and functions 100% through all my pistols, I bought another mold, milled it shorter and removed the lube groove to cast a 105 grain TC for 380 use. The design is just as reliable and accurate in my most finicky 380s.

OK: I'll bite!

How do you mill a hole shorter and remove the lube groove?

For some reason I just can't wrap my mind around this concept...

Cheers!