alloy advice needed

[oldroger]

I need advice on alloys. I am about to restart casting after a 40 year layoff. I will be casting .45acp (452630 &460) & 10mm (no molds yet) to be shot in M1911 and S&W pistols at 950-1000 fps.
I have been doing some research, reading posts here, obviously very knowledgeable people here. Special thanks to grumpy one for his work!
When I last cast we were using Lyman #2, diluted with two parts of MOL pure lead, usually lead pipe. This mix resulted in about 1.7/1.7 - Sb/Sn alloy. We had the mix tested a couple of times (I had a friend who worked in the wet lab) and there was usually a trace of As doubtless from the pipe and other scrap. We always dropped the boolits from the mold into ambient water. I have no idea how hard the boolits were even though I had access to all sorts of elaborate hardness testing equipment. IMO there is no way to do a conventional Brinell test on anything as small as most cast boolits.
I have linotype and MOL pure lead, I propose to dilute the lino to below 2% Sb and add enough Sn to get up to about a 1.5/1.5 alloy or a bit less. I mix on a Coleman Stove and am limited to about a 30# batch at which point my comfort level is exceeded due to the flimsy nature of the stove. I know that this isn’t the cheapest way to go. But, it should give me high quality!
Anyone see any loopholes in this plan?

[randyrat]

I'm thinking out loud...... If you cut your linotype that much you will still have about 1% tin left and you may be OK for casting. I can't see any problem with the 45 acp and pressure,but your 10mm may need a different alloy being 35,000 psi or a little more.Unless you can load it with mouse fart loads.Those high pressure rounds ie...9mm,40 cal,10mm can be a real challange, they will give you a new respect for the good Ol 45 acp and cast. Although not impossible,don't get me wrong. I shot a lot of 40 cal with cast bullets, accurately and no leading.

[454PB]

Welcome to the forum!

If you still plan to harden by water quenching, you could use 2 parts lead to 1 part linotype. You'll end up with a hardness around 27 BHN, which should stand up well for any of the calibers and pressures you mentioned, and won't require the addition of any Sn. Arsenic is not required for heat treating.

[Cherokee]

The only negative to a soft alloy in 45 ACP is feeding - the soft lead may not slide up the ramp of a 1911 like it should. For the 10mm, I am using 1% tin and WW air cooled, but not pushig to top pressures. No feeding issues in that 1911. Try it first, then go a little harder if need be for reliable feeding.

[oldroger]

Thanks to all for your observations. I have seen a bit of failure to feed problems w/1911 in commercially cast H&G 68 style rounds. This is in one of my pistols with a ramped barrel. It looks exactly as if had hit the brakes and stopped on the feed ramp.
These boolets are said to be "hard cast" but almost all commercial casters say hard cast. They certainly seem hard enough to the scratch test.
Is it the hardness or the presence of Sn or Sb which makes the boolet more slippery?

[leftiye]

Could be the Lee mule snot on the boolit nose! Harder would make it not "grab" as much. But there might be more going on than lead boolits with that failure to feed, IMHO.

[oldroger]

Could be other problems I suppose, but it feeds 200 gr HAP jackeded rounds nearly the same shape like a champ.

[runfiverun]

i have to seat h&g's right flush in my 1911 for them to feed well.
i would use the mix you propose and just water-drop it.
not for my 45 but for yours.