I have a small problem

[TX Jack]

I have casted a few pistol bullets but have now started on rifle bullets casting with a Lyman 457193 mould. This mould casts a 410 gr bullet with wheel weights but I am currently using some harder lead for a 395 gr bullet.
I just dropped about 100 bullets and noticed that part of one side of the bullets looked a little frosty. I thought is was just a little overheating but odd that only part of the bullet was frosted.
When I went to lube/size them I noticed the frosty part was coated with excess lube. I got the dial caliper out and found that this part of the bullet was undersized. Some as much as .010" undersize. The bullets are not round in the middle. The base and nose look good but the frosty part is in the middle on one side and it is like the mould did not fill out here. The bullets look good but the dial caliper tells the story. No way will these bullets shoot good.
I sprayed the mould with "drop out" from Midway before I started casting. Could this have clogged the vent grooves? Might that be the problem? Any advice is greatly appreciated.

[HammerMTB]

I've tried the Drop-out product. It has a drawback-just what you describe, that it takes up space.
I recommend you clean that gunk out, melt those boos, and try again. You don't need a release compound to get boolits to drop. You DO need good filled out boolits for accuracy and to prevent leading.

[canyon-ghost]

Whenever you start with a new mold, it's best to make sure that it's clean and dry. I use an ordinary bore brush, and some Hoppes #9 and give it a good brushing, inside and out. I dry it with a rag, then pour alcohol or acetone over it. Using Rubbing Alcohol means that a certain percent will be water, dry it with a rag again. Wipe them down really good. I haven't used drop-out, have smoked the cavities with a match (or several). Smoked, sooted, either term applies.
If one side is drawing away from the mold, it sounds a whole lot like contaminants. You may want to turn up the heat and burn it out, if you cast that much, or preheat the mold and pour hot.
Hope that helps some,
Ron

[geargnasher]

Welcome from the other side of Central! You enjoying the humidity as much as we are?

Lyman moulds cast best when the cavities are ABOSOLUTELY CLEAN. If you have to smoke them or use mould release you have other problems with the mould that need to be addressed. Hot, soapy water and a toothbrush, or boil the blocks in a saucepan with dawn and distilled water is a good way to clean them. Brake cleaner and a nylon bristle toothbrush works well too. Get the cavities spotless and totally degreased and they will cast great.

Now for my stab at what is actually your problem: If part of the mould is too hot, the lead will "shy" away from that area just like it will from a cold spot, causting uneven fillout. Difference is that cold "shying" areas with wheel weight metal or anything containing antimony show up as very shiny, whereas hot "shying" is very dull and has a sandblasted look. I think you had a hot spot in the blocks, not uncommon with very high antimonial alloys like you're using and the large cavities in undersized blocks.

I feel that the Lyman double cavity mould blocks are too thin in the girth for .45 Caliber boolits. Not sure if yours is single or not, I kind of get the impression it is, but there could be a hot spot there for any number of technique-related reasons.

Try casting with a cooler alloy and possibly a cooler mould (turn down the pot and slow your casting rhythm a few seconds each pour).

Gear

[lwknight]

The harder alloy probably has more tin in it and is more susceptible to the shrunken band syndrome caused by the molds getting too hot. The mold getting too hot is easy to diagnose. First and most prominent tell tale in the nose always looks good while there are frosty bands near the base.

[44man]

Hot spot is correct. Harder lead needs less heat and large cavity Lyman molds need a slower pace.
Most guys cast way too fast for quantity and wind up tossing most back in the pot.

[w30wcf]

If the base band is aok you may find those bullets may shoot aok at lower velocities if they are indexed into the chamber. Just mark the nose of the bullet in relation to the low spot and chamber the cartridges with the mark at 12 o'clock.

As far as the problem goes our fellow bullet casters have given great advice.

w30wcf

[jmsj]

TX Jack,
Welcome the site,
I use a similar Midway product but not in my bullet molds. If I have a ingot mold (homemade) that stick a little, I find that it helps. But like others have posted, I keep the inside of my molds as clean as possible.
Adjusting your melt tempature and casting pace is another important factor. I find a thermometer in the melt useful for dialing in what tempature works best for a paticular mold.
jmsj