Cast bullets for an auto pistol

Down the rabbit hole into the esoteric. Before the current ammo shortage I decided to start casting bullets, just because I liked the idea of an extra level of independence. The 30-30 cast bullets worked OK but there’s more to do there. This time though its the 10 mm Auto.

I’ve been loading the Hornady 180 XTPs with good results, but I wanted a 200 grain cast bullet too. The RCBS 200 SWC has gotten good reviews so I got that two cavity mold a while back. The mold handles I use for the Lyman molds didn’t fit the new RCBS mold, and people were starting to run low on things. Buffalo Arms in Idaho sells a hand-fabricated-looking handle set that works like a pair of Vice-Grips. Pretty expensive and heavy, but they had them in stock. They’re great. You get VERY consistent closing pressure for each pour. I weighed 20 already lubed bullets tonight and the extreme spread was 1.5 grains, 201 gr +/- .75.

Of course, to “save money” casting bullets from one dollar per pound lead, I had to buy a lube sizer. Seating the lead bullets, I was shaving lead on the case mouths, so I bought a 10 mm M die. It expands deeper into the case than a regular expander die, plus it makes a wider spot at the mouth. I’d been seating crimping in one swipe with the jacketed bullets, but since that’s not really an option for cast, I had to readjust my otherwise permanently adjusted seating die. Now I figure I’ll buy another seat die in this “money saving” venture.

To prevent the case mouth shaving lead from the bullet upon seating, I had to put LOTS more flair on the cases. I tried chamfering the mouths a little and that didn’t help much, so now I’m working the brass a lot more, which means it will work harden sooner. The bullets aren’t getting shaved now, but the cases are so wide at the mouth that the seating die can’t be lowered nearly as much as normal or the crimp taper starts to erase that wide belling, shaving lead anyway. And that means that the seating stem is just a bit too short, so with the locking collar removed from the seating stem and the stem screwed in as far as it will go, I still have to screw the die body down to where it is narrowing the flair just a bit. That means there is no support on the case at all except at the very mouth. I noticed that if I nicely align the bullets on the case mouth by hand before seating, they now don’t get shaved. When the bullets shave, the lead that’s stuck in front of the case mouth interferes with head spacing. It’s not serious, but it is annoying.

Loading dies, at least for straight wall auto cases, are not made with cast bullets in mind. These are RCBS dies, but I doubt there’d be much difference. The whole paradigm is wrong. Since you apparently need much more flair at the mouth, and you’re shoving the case up into the die mouth-first, your die has to be too large to support any part of the case except for the very mouth, or else it will erase your mouth flair. Instead of going mouth-first into the seating die, the cases should be going head-first into a support die, and then up to a seating stem, with the bullet pre aligned before it touches the case. That way, much of the case, and all of the bullet’s drive bands, could be aligned prior to seating. It couldn’t be done “right”, in my opinion, any other way.

But we make it work, somehow, with what we have. There’s still more testing to do, but initially I got two groups of just under 5 inches at 20 yards standing unsupported. Lots more recoil than the 180 XTP loads, but my chrono got lost along a 20 mile stretch of highway in a snowstorm so no vel data. A third group was MUCH larger, so I quit. There was leading in the Lone Wolf barrel. That was before I eliminated the lead shaving at seating. We’ll see later whether the shaving verses not shaving makes any difference.

The load is 9.4 grains Blue Dot, CCI 300, OAL 1.255, #2 alloy, Super Molly lube that came with the Lyman sizer. Still don’t know if it’s a keeper, but I do know I can get off at least 10 decent shots. Whoopie, eh?


10 thoughts on “Cast bullets for an auto pistol

  1. I shot IPSC with a Glock 20 for a couple of years, running cast bullets in the stock barrel – didn’t know I wasn’t supposed to. Gun leaded up something fierce, but was accurate enough for competition at my level.

    I didn’t seem to be having that many issues with lead shaving or bullet seating. I was using Lee dies, I believe, in my RCBS press. Did require a bit more flare than a jacketed bullet would. I also used the factory crimp die to assure they’d chamber.

  2. The answer is gas-checks. Another die if you do them yourself, and you have to cast/size them a thousandth smaller, but they eliminate the lead-shaving and most of the barrel leading, too. The standard flare your expander die provides is enough flare for gas-checked boolits.

    I don’t mold my own, but buy Oregon Trail ready-made. They have an up-line of gas-checked boolits called “Laser-cast” that are a very hard lead, for rifles, and those won’t lead barrels below 2,000 fps.

    Happy lead-slinging!

  3. Gas checks are the answer, as stated above.

    Or you can use punched circles of shirt cardboard (same effect as the more expensive copper or aluminum gas checks, at 1/50th the cost). Just put them over the powder and under the bullet.

    Buy a punch at Harbor Freight that is slightly larger than your case mouth. This has the advantage of holding your powder tight to the base of the cartridge.

    • I wanted to keep things simple. I use gas checks in the 30-30 for velocity up to about 2K fps from a 16″ barrel. There are people using plain-base bullets in 44 magnum and getting good results. I think if things are tweaked properly one should be able to use plain based bullets in the 10 mm without too much trouble.

  4. Better yet get a sizing die that is ~.001 smaller then the one you are using. In the old days Lyman sold sizing dies in about three sizes for every caliber that they made a mold for, dunno about now.. That should size the cast bullet down just enough to let it slide into a “normal” case-mouth bell.

    And putting the gas check on will let you pump up the load as well, as the who;e point of the check is to keep the projectile base from distorting due to the powder flash.

  5. You DID slug the barrel and bought a sizing die .001 larger than barrel size, right?

    • The bore slugs to .400″ groove dia. The sizer is spec’d at .401″, which for the moment I consider to be the minimum diameter bullet in a .400″ groove bore. The sized bullets are measuring at .4008″ to .4009″ as best I can measure them. Some people us bullets up to around three thou over the groove dia. Also the bore itself can make a big difference. The finish, any taper or diameter variances can cause complications. Some say the ideal bore for naked lead is one that tapers gradually smaller toward the muzzle, and of course has a mirror finish.

      I have some more playing around with loads to do before I think about putting the sizing die on the lathe to open it up. Same velocity, with a different powder, has been known ot help or hurt a lot, or so people claim. Assuming a nice bore and a good fit, some people say it’s all about peak pressure, and that actual velocity has practically nothing to do with it per se. I can certainly see the logic there. And of course there is the idea that one lube will give zero leading and some other lube will result in lots of leading, all else being equal.

      So there are a lot of variables that all need to come together. That’s why I giggle when people state their cast bullet loads by giving only the bullet mold number, the powder and the charge weight (no alloy or lube identified, and no mention of bore to bullet size, etc.).

      Load manuals of course normally don’t address cast bullets, and when they do it’s often just reduced “cowboy” loads but I do have the Lyman Cast Bullet Handbook, which is not terrible, but it still does not address lubes in the data, nor does it use different primers for different powder like Speer does, so you may have a Lyman load for an ass ton of powder using a regular primer, but Speer lists the same powder with a much smaller max charge, but a magnum primer.

      There’s still a lot of Voodoo involved, so I must put on my loin cloth, don my face paint, my bear claw necklace, ankle bracelets and my rattle, and dance around the fire, chanting, so to speak.

  6. The harder lubes that need to be warmed up will help with that, and leave less gunk in the mechanism. I made a gizmo with a clothes iron element running at reduced power, but a hair dryer will get you started.

  7. I use gas-checks on all rifle bullets. And any pistol above target .38 Special loads; no matter what lube and such, always get some lead fouling.

    B, never heard of using the cardboard that way, will have to give it a try.

    Yeah, for some bullets I have to flare the case mouth more than others, depending on the bullet; sometimes enough that starting it into the seating die you can feel it.

  8. I have the Lyman 4500 with the heater. It’s fairly common to use wool felt wads in a percussion black powder pistol, up to or even exceeding 40 S&W energies, and I’ve used cards to segregate the powder from the black powder lube, so using cardboard in the 10 mm doesn not sound crazy. I’d just rather not need to. We’ll see. This bullet is not designed for gas checks, and so I’d have to get another mold to use them. I read about a 100K words on this 200 grain RCBS mold, on the fora, before I bought it.

    Another thing I will try is the alloy RCBS says the mold is designed for, which is 10 to one (ten parts lead to one part tin, by weight). You never know, or rather, I don’t know.

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