molds casting undersize boolits

[Captain Capsize]

I have two Lee molds that are casting out of round and undersize boolits. One is .309 casting .306 the other is .311 casting .308. Both cast out of round boolits. I have found that I need to use the .311 boolits in my Marlin 30-30. sized them through my .308 sizer to make them round. But I don't like the 3" groups at 50 yds.

I am wondering if I can increase the size of the mold cavities by reaming out the cavity by using a boolit and polishing compound if I drill a hole in a boolit and put a screw in it and spin it with a drill press. I am not sure this will work since the lead is so much softer than the aluminum mold blocks. has anybody tried this?

[462]

Captain Capsize,

That's how I do it, except with a cordless drill.

P.S. With a name like that, I'm glad your boat is in Flordia and mine is in California. ;)

[HeavyMetal]

Lapping a mold is pretty easy to do and should be covered in one or more posts in the Stickies section of this site.

Before you do that I'd like to ask a few questions pertaining to the boolits you have been casting so far.

Please bear with me as I see you only have two posts and I'm not certain how much experience you have. Please do not take this as a critique but as a search for an easy answer.

What alloy are you using? straight wheel weight metal can be very hard to get good fillout with if your casting on the cool side.

Have you examined the boolits you've already cast under a strong magnifiying glass before you sized them? What I'm looking for here is completely filled out boolits with sharply defined bands and no rounded edges any place!

If these conditions exist I will suggest you turn the heat up a little, dip a corner of the mold in your alloy until the metal will not stick to it and add a little Tin, from 95 5 lead free solder.

2% is the suggested addition of tin and in a ten pound pot this will be about 3 ounces of solder. Tin will help fillout and is not a hardening agent but rather a "serfactant' that will help the alloy flow into all the nooks and crannies of your mold.

If you have done all this and you still have undersized and out of round boolits then go to lapping the mold.

[SciFiJim]

Captain, Do a search for "Leementing". There is a ton of stuff to help you out on this forum. But, if it was me with molds that far out of spec, I would return them as defective.

[RayinNH]

Try beagling first it won't alter the mould like lapping will do...Ray

[243winxb]

Adding antimony or linotype will made the boolits larger in diameter. From lees website >
Increasing mold diameter

If you need the mold diameter of your cast bullets to be increased just slightly, there is a way to accomplish this with negligible ballistic results.

With the mold open, be sure you liberally lube the mold blocks in front of and behind the bullet cavity. Place a small section of cigarette paper or writing paper to the lubed block . This prevents it from burning.

When casting the bullet, the diameter of the bullet will be increased by the paper width. You can actually go up to about .010 before you begin to see lead flashing appear. While the bullet will be slightly "out of round", this very minimum amount will not effect accuracy or the manner in which the bullet travels through the forcing cone and barrel of your gun.

[WHITETAIL]

:castmine:Cap, Welcome to the forum!
Call Lee, and then send them back.
The worst that could happen is they
send you a new mold with the same
problem.:coffee:

[MtGun44]

Also, sizing .308 is unlikely to provide best accy in .30-30. Try at least .309. I normally
use .310 or .311 for all nominal .308 calibers like .30-30, .308, .30-06, .30-40. I don't do a huge
amount of cast in rifles, tho.

Bill

[Captain Capsize]

Thanks for your replys, I am somewhat new to casting and have much to learn any advice will be appreciated. I am a long time shooter and reloader but am learning a new art.

As to the handle "Captain Capsize" a sailing buddy pinned that on me 25 years ago when I capsized my home built 28' catamaran the first time I sailed it. I haven't turned one over since but it stuck.