My mold is dropping boolits slightly undersized

[jamesp81]

I have a Lee .452 200gr SWC mold. I'm using WW alloy. In my last casting session I ran the pot temp and mold temp as cool as I could. I had my Lee pot's thermostat set on 3.

Boolits tend to come out .452 to .453 at their widest point and .4505 to .451 at the narrowest point. There's not enough there for the sizer to make them .452 all the way around.

I am looking at multiple solutions. I wanted to ask those here way smarter than I what my best choice is here.

1. Alloy in some tin. When I first started using my Lee pot I was running it way too hot. I may have lost a good bit of tin in my alloy when I ran hot. I could alloy in some tin to replace what was lost.

2. Beagle the mold with aluminum tape. They'll drop out of round but the sizer die will work that out.

3. Alloy in some super hard from Rotometals or some Linotype. Raising antimony content is supposed to increase diameter of boolits.

Which is my best course of action?

[Motor]

You know I've complained about this several times before. All of my old Lee moulds drop big and I love em but the newer ones drop on size at best but mostly undersize.

My worst one I used aircraft aluminum tape on to beagle it and it works ok and although the boolits are not perfectly round even after sizing it doesn't seem to have a negative effect.

Now I don't only beagle them but about 2 or so years ago I decided to try shake and bake powder coating. Powder coating adds a little to your boolit diameter which along with all the other great benefits is perfect medicine for slightly undersized boolits.

So now I don't hate my newer Lee moulds as much.

Motor

[JSnover]

The "Lee-Menting" thread has all the answers to your problem. It's easy to do, kind of a fun way to kill some time. I've lapped two molds (a Hoch and Lee). The boolits drop easy, look great and they're right on size.

[toallmy]

Last weakened I lapped a saeco 2 cavity wad cutter mold that dropped at .357-.3575 and I want to size to .358 . Now they drop at .358-.3585 . I spent more time thinking about it then it takes to do it . Just remember to go slow you can take more out later , but you can't put it back . Aluminum will open up really fast really really fast you can open up a lee with Ajax . Honestly powder coating is a good fix for a under size mold , but I make such a mess , and am to lazy to power coat . But be ready to mess up the mold it can happen . Just a thought

[w5pv]

Try increasing the sn in your melt,I use a strip about 10" long 1/8 in dia a 20# Lyman Pot.My 124 grain bullets come out at a 129 grains.The sn I use is 99% pure.

[OS OK]

A page from Lyman 'Reloading and Cast Bullet Guide' circa...10/93


Attachment 191462

[Mk42gunner]

OS OK,

Thanks for posting that chart; I had never seen it, and it looks like some very good information.

Robert

[runfiverun]

right out of Lyman number-3 about page 58 or so.

I'd lap the mold.
you shouldn't open the correct sides too much but should cut the too small sides easily.
and it will be round.
heat the mold first.

[Shiloh]

Adding antimony to your melt will help. Getting where you need to be is the question.

SHilh

[Maven]

I'd also recommend purchasing a casting thermometer since uniform temperatures correlate with more uniform CB diameters.

[Larry Gibson]

No need to lap the mould. Add 2% tin and increase the alloy temp. You actually want it 710 - 725 degrees for good fill out. Also hold the spout not more than 1/2" from the spout and get the hot alloy into the mould as quick as possible by adjusting the spout stop. Leave a good sprue on top of the sprue plate to harden. Adjust your casting tempo so the bullets do not frost. Adjust the casting tempo so the mould does not cool between castings. Too cool an alloy, too little tin in a ternary alloy and not filling the cavity quick enough are the main causes of out of round and/or wrinkled bullets.

Larry Gibson

[Harry Tobin]

Which 200 swc mold you have?

452-200-SWC.............................. TL452-200SWC

I had both styles and the first was the tumble lube type and that went junk pile. Then I got the 1 groove style. The tumble lube had such fine lines when lapping it all went away, the one groove style I got was undersized too, plus out of round. But that one lapped in fine, lapped a bit and dropped a few bullets and then sized to look at the base and if it wasn’t cut all the way around I’d lap it again. That also cleared up my leading issues, hope this helps
And as others said get a casting thermometer and you want to be in that 725 range

[runfiverun]

left one.

tin is the answer to all undersized molds [rolling the hell out of my eyes]
a nice oblong shaped sorta right sized too big boolit is exactly what I want from my molds.

i'll take the time to make nice round ones the correct size.
do what you want.

[GhostHawk]

I have been known to take a handful of undersized boolits, stand them up one at a time on an anvil, and smack them hard one time with a hard rubber mallet. Then they size. Straightens their attitude right out.

Does not appear to change the basic shape at all, just makes them a shade shorter and wider.

Tough to do with tall .30 cal bullets. Pretty darn easy with nice fat .452's.

[jamesp81]

Which 200 swc mold you have?

452-200-SWC.............................. TL452-200SWC

I had both styles and the first was the tumble lube type and that went junk pile. Then I got the 1 groove style. The tumble lube had such fine lines when lapping it all went away, the one groove style I got was undersized too, plus out of round. But that one lapped in fine, lapped a bit and dropped a few bullets and then sized to look at the base and if it wasn’t cut all the way around I’d lap it again. That also cleared up my leading issues, hope this helps
And as others said get a casting thermometer and you want to be in that 725 range

Left hand design is what I have.

[jamesp81]

For those who have lapped their molds, what did you use for compound? The only things I have on hand are 220 grit Wheeler Engineering scope ring lapping compound and Bar Keepers Friend. I refuse to use the scope ring compound. It embeds in metal really easily and does NOT come out.

Will the Bar Keepers friend work or should I get some valve grinding compound, maybe 600 grit or so?

Edit: Just remembered, I also have Mothers Mag aluminum polish.

[Super Sneaky Steve]

You could just powdercoat the boolits. It should add enough to put you in spec.

[jamesp81]

You could just powdercoat the boolits. It should add enough to put you in spec.

I may yet. I want to get some tumble lubed bullets to shoot, just to prove to myself I can do it.

[Motor]

I may yet. I want to get some tumble lubed bullets to shoot, just to prove to myself I can do it.

Many of my moulds are tumble lube (just like the one above that "went junk pile" and I love em but I PC them all now.

I'm still trying to figure out what to do with 8 bottles of A-Lox.

Motor

[Harry Tobin]

For those who have lapped their molds, what did you use for compound? The only things I have on hand are 220 grit Wheeler Engineering scope ring lapping compound and Bar Keepers Friend. I refuse to use the scope ring compound. It embeds in metal really easily and does NOT come out.

Will the Bar Keepers friend work or should I get some valve grinding compound, maybe 600 grit or so?

Edit: Just remembered, I also have Mothers Mag aluminum polish.

The mold I opened were aluminum and I used the finest valve grinding compound I had but still a bit on the coarse, I think around 220. That was a two cavity mold I did, I cast a handful of bullets keeping them separate. That was a 45 SWC mold, and looking back I should have cut the bullet tip off. Don’t need to make the tip any bigger. So did it with valve grinding compound first then what I had on hand was automotive rubbing compound and used that for the final clean up. Cast a few checked the size and did a few times till I got to the size I needed. Just clean the mold with brake clean and still went in with Q-Tips and lacquer thinner. It worked for me, and did a 9mm the same way and both still throw good bullets