Different weights of different alloys?

[JeepsAndGuns]

Curious how much the different alloys of lead can effect bullet weight.
I have a bunch of lead ingots from various sources. Some was from some melted down bird shot, some was wheel weights, some was ingots bought online that had pure lead and some linotype.
Some were mixed together and some are specific type. (I had to re melt and re cast all of it because of dirt and corrosion). So some may be a mix, some may be all birdshot, some might be a mix of them (cast at different times). All the ingots are just mixed together.
All I am using it for is about 90% 12ga slugs and the rest would be buckshot (which I have not started casting yet).
Some times I can cast some slugs and they weighed 520 grains. Another time I cast some and they weighed 518 grains. So it would seem the majority type of lead alloy that happens to be in the pot is effecting the slug weights.
So it got me curious how much a bullets weight can be effected by the other metals in the lead.
Lets just say for example, you have a bullet mold that will make a 200 grain bullet using pure lead. How much will that bullet weigh with the main/most common different alloys? What about wheel weights, etc..
Anyone ever tested this?

Just to clarify, it is not a issue for me, as the loads I am using are made for the weight of the slug for pure lead, so the slug coming out a little light is of no issue. I am just using them for range fun. I do not hunt or use them for anything but smacking hanging steel plates or water jugs.
I am mainly just curious about what effects the weight and by how much.

I have been meaning to get a pot large enough to melt everything I have down and mix it all together and make it a uniform mix. I just have not got around to finding/buying one yet.

[JimB..]

Alloy matters, but the minor variance you’re seeing could easily be explained by pot temp as well.

You could figure out estimated weights by calculating the percentage of each element times the density of each element in the alloy. The less lead, the lighter the bullet.

[243winxb]

Pure lead/heaviest. High percent of antimony/lighter/harder/less shrinkage. My test- https://www.thehighroad.org/index.php?media/weights-diameters-test.4081/full

Harder alloys spring back more after sizing.

[Winger Ed.]

To have the weight come out right, you need to use the same alloy they did when they designed the mold.
Lyman #2 is a favorite.

I cast a bunch with a common .45 cal. 405 grain mold.
Using Lyman #2 alloy, it comes out right.

The softer alloy I use, and load to trap door speeds with it come out around 420 gr.

[OS OK]

https://i.imgur.com/KUVGPNE.jpg

[zarrinvz24]

Thanks for sharing that chart OS_OK. That is a nice quick reference.

[JeepsAndGuns]

Thanks for the info/charts 243winxb and OS OK. That really help answer my questions!
I am very surprised at the weight difference between pure lead and the others. I was not expecting that much of a difference.

[FLINTNFIRE]

Most slugs like most black powder bullet molds are cut for pure lead as size is a difference in alloyed lead compared to pure , shrinkage or no shrinkage , softness for loading or expansion at speed also enters into play .

Since most muzzle loader and shotgun slugs are not sized spring back was not a consideration , size after cooling is .

Pure lead is the heavy , alloyed is lighter and harder , as to buckshot it was usually harder the pure , deformation being a consideration .

2 grain variation on a 520 grain slug out of a shotgun at the ranges one would be using it does not seem to be as important as shooting rifle at long range .