Cast bullet size difference

[Hawks Feather]

I had done some favors for a friend who also does some bullet casting. As a way of saying thanks he gave me a couple hundred 172 grain bullets for my .40. I had a pretty decent supply of 'factory' cast and have been using them, but today I was cleaning some things out and found them. I have just purchased a Lee .401 sizing die for when I cast my own .40 and thought I would see how it worked. It worked fine, but I had some bullets that it really sized and some that it didn’t even touch. Now I know that it is the problem with the bullets (not the sizer) and possibly the way they were made. To try to avoid doing something like this myself, does anyone know what could cause this much variation?

Thanks,

Jerry

[Yodogsandman]

Casting temperature wasn't maintained. The temperature of the alloy while casting was allowed to vary quite a bit.

[MT Chambers]

It could also be that they were cast from diff. alloys for some reason, maybe cast on diff. days?

[bedbugbilly]

I'm not a "high tech" caster. I've been casting for 50 + years in a 10# pot with a Lyman bottom pour ladle over a single propane gas burner. So . . . obviously I can get temperature variations. I also don't fool with alloying, etc. I cast pure lead for muzzle loading and "range lead" for my cartridges. I'm explaining this just so you know that I'm not a high tech with electric pot, PID, etc.

That said . . . I have the same issues from time to time. I don't cast or reload the 40 but do cast and load a lot of 38s. I use a Lee push through sizer when I do size. I usually purchase m "range lead" from members on here so as "range lead", who really knows just what the alloy is?

Anyway . . . I attribute the difference in size of mine to several things. Make up of the "range lead", temperature of the pot and even the quantity of metal in the pot. After using my "hot plate" for so many years, I pretty much know the adjustment of the valve (gas) but I'm sure there are temperature variations. When casting, and we all do this I'm sure, as the pot gets lower, you add some. I'm sure that I don't always wait until it is "up to temperature" if I'm casting and add more . . . it melts, my mold is hot so I start to pour and if they fill out fine, I keep going.

Luckily, most of my molds I can load "as cast". Yes, there may be a variation of as much as + or - .0005 and sometimes a bit more . . . but since they are lead and as long as they are oversize of the bore and work with the neck tension, I load 'em and shoot 'em. I do have several old Ideal molds that are .360 that I do size down but that's about it.

I'm not a competitive shooter - just a "plinker". If I did shoot competition, I might be a little more fussy about the sizing, I don't know. I do respect those who are really into the casting and have the equipment where they can control temps, alloys, etc. better but at my age, I'm too old to change things and add all those things.

On the straight walled 38s, I think you can get away with more "variations" than with a tapered case like a 9mm, etc. Again, I don't load the 40 so I'm not sure how a variation would affect the finished cartridge as far as head spacing on the shoulder or how well a minor variation wold work in a particular hand gun? I'd like to know as I'm just not familiar with the 40.

When you do start your casting . . you at least have a decent sizer and if oversize, you can take care of the problem to keep them all consistent. If they are undersize . . if not by much, you can always cull them out and either re-melt or set them aside for plinking.

[Wayne Smith]

Just out of curiosity, if you segregated the tight and fitting boolits, try weighing them and see if there is a difference that goes beyond, say, 10% of total weight. I doubt there will be.

[243winxb]

High antimony % = Larger bullet diameters .