I've been handloading for almost 40 years but, new to casting. I wondered if mixing pure lead and roughly half wheel weights would be ok to use for .45 bullets. The reason I'm asking, is I have several pounds of pure, and wanted to use it. The .45 bullets shouldn't be faster than about 850 fps or so. Thanks.

Sure, I do it. The wheel weights add a bit of tin, which helps mold fillout.

Be careful you don't grab zinc wheel weights.

Stick-on weights are usually (always?) pure lead.

Regards.

That's about it in a nutshell!

Your .45 ACP bullets don't have to be hard as sin. In fact the only time I had a leading problem in a 1911 Colt was when I cast a boat load of 230 RN's out of an ungodly hard alloy consisting of mostly monotype. My young self probably intuited that harder was better to avoid leading, and it took an old friend to disabuse me of that notion.

Yup, works great. I used to have a large supply of ww's but it was been dwindling and I'm stretching out the supply. For 38 specials and 45's I cut them either 50/50 or two parts pure and one part ww's.

I go roughly 50/50 and tip the scales a little bit more in the WW area for range or plinking.

My pure lead runs about 5.5 to 6 on my hardness tester. My old scrap WW's run about a 14 BHN. A 50/50 mix gives me about a 10.5 BHN.10.5 should easily handle 1200fps. A pure lead bullet should be able to handle 850fps .

It works. As stated you can cut it with less as than that. As an aside I casted half and half for an Italian Sharps I have in 40\65 and it worked wonderful.

38's and 45acp you can go to 3 parts pure to 1 part WW and still be perfectly fine. I have run 308win up to 2200fps with 50/50 mix. And if you are powder coating the bullets hardness doesn't matter on low pressure loads one bit.

Agreed all. +2 over groove bullets are key to good cast loads. Off course here are anomalies but it’s the place to start.

50/50 should work fine you can water drop them if you want, won't hurt anything.

50/50 is about a perfect alloy for a 45 ACP. You could add a bit more pure if you want. It's not the velocity that is the limiting factor with cast bullets, it is the pressure. There is a link to some really good reading from LASC (Los Angeles Silhouette Club) on the Castboolits website which explains much better than I can. The pressures at which a 45 operates will not cause issues with the alloy you are speaking about. I use the same in my 45-70, 30-30, and 444 loads.
Good luck, and take care!
Rick

A lot of casters use 50/50 Clip-on/Stick-on weights with 2% tin added. You could try it first without the Tin to see how they fill out.

I used to mix ww with 4% tin to get a good hard easy casting alloy.