Casting lite

[Nikkisdad]

My Lee over sized mold should be dropping a 478 grain bullet but consistently will drop only 455 plus or minus 5 grain bullets - how come? The lead is pure and no additives added to the recipe such as tin. I need very soft bullets for black powder (.58cal Zouve). Am I doing something wrong here, please advise..thanks Manny

[MtGun44]

Most likely your lead is not pure. Tin is 36% lighter than lead, so if you have
a bit of tin, the alloy will cast much lighter. Tin hardens only moderately by
itself, so it may be soft, but not pure.

You are casting about 5% light, so your alloy density is 95% of the density
used by Lee to calibrate the design. IF they used pure Pb, which seems
fairly reasonable for a BP mold, and IF you ONLY have Pb and Sn in your
alloy (if it is really soft, then this might be true) you would have about
10% Sn, which is a lot of Sn. Typically 2% or so Sn is used to improve
fill out, and most alloys used for boolits use antimony and arsenic to
harden them.

Bill

[Nikkisdad]

Should I skim off the grey tin that floats on top to increase the weight of the bullet? Or will this effect the fill out of the bullet while casting?

[captaint]

If it were me, I would leave the tin right there. The twenty odd grains less weight shouldn't be that big a deal. You'll get better filled out boolits with the tin in the mix. enjoy Mike

[Nikkisdad]

Good idea Capt, I'll see how they shoot when it warms up in Up State NY. Just hope they are soft enough to catch/expand the rifling on my Zouave musket.

[MtGun44]

Yes, leave it alone. The weight is not critical. NOTE that I said "IF"
a bunch in the previous post.

Bill

[cbrick]

Since you didn't mention in your first post how they are casting I'll assume the fill out is good and they are just lighter than you expected.

If it is tin and it probably is it will add only a very little hardness to the alloy, tin does add hardness just not very much. Most of the front stuffers I've talked to say they add a bit of tin to their alloy just for the castability. I suggest shooting them and see, the gun will tell you if it's happy.

Rick

[Nikkisdad]

They appear to be casting pretty good, I will do as suggested and give them a go when I get a chance, the weather here is and will be crappy for quite some time will wait for spring. Thank you for your reply's.......Manny

[MtGun44]

Good luck!

Bill