Prpblem with a Lee mould

[Down South]

I recently bought several new Lee moulds. I broke in the last one yesterday afternoon. The Mould is a 401-175-TC. After a good cleaning and prepping the mould was casting good boolits or so I thought. After measuring the boolits I found a problem. The boolits measure .4005” in the area that would be across the blocks and .405 with the blocks. The mould halves are not matching up perfectly when they are closed.
I am not an expert by any means and am new to casting. My question is. Is the mould too far out of spec or not? I’ll be sizing the boolits to .401

[44man]

I would say it is. Lee should replace it for you, call them.

[Ranch Dog]

After the work of casting, I think I would size them (look at them again) and then shoot them to see how they do.

An aluminum mold is going to expand with the heat, and it will expand along the seam. In other words, you will always find a difference in the two diameters measured across and along the seam. I really don't know how much a difference is acceptable, that might be a personal preference based on performance.

I'm going through a lot of trouble to understand how it can be controlled by recording the results of each of my casting sessions (see the image from my casting database). Alloy temperature is what causes the stretch but there has to be some point in temperature that the stretch is controlled and all the other aspects of casting that are effected by temperature (fill, weight, etc.) are fulfilled. I've found that I can make a mold do just about anything I want with either alloy or temperature or both. As an example, I use one mold to cast for two very different 444 Marlin rifles. One needs a .431" bullet and the other a .433" bullet. To get that big bullet, I'm simply cast at 950° vs. 750°. That difference in temperature makes the difference in diameter as the aluminum blocks are going to respond through expansion. The bullets are out of round, but they size up very nice and round with a .433" sizer if they are pushed through within about 24 hours.

If you are going to size the bullets, I've found them to be quite malleable for the first 24 hour period and they tend to round out very well. I kind of view each new bullet sitting on the bench as a little living beast with a life span of about 7 days. Changes are taking place but I'm still trying to figure them out. That's about all I have to offer. I think I would shoot them and make sure its not something I would miss if I sent it back (done that too).

[Ranch Dog]

I'm not disagreeing with 44man's suggestion as I value his opinion and the outcome might end up being the same for the mold but after the work of casting, I think I would size them (look at them again) and then shoot them to see how they do.

An aluminum mold is going to expand with the heat, and it will expand along the seam. In other words, you will always find a difference in the two diameters measured across and along the seam. I really don't know how much a difference is acceptable, that might be a personal preference based on performance.

I'm going through a lot of trouble to understand how it can be controlled by recording the results of each of my casting sessions (see the image from my casting database). Alloy temperature is what causes the stretch but there has to be some point in temperature that the stretch is controlled and all the other aspects of casting that are effected by temperature (fill, weight, etc.) are fulfilled. I've found that I can make a mold do just about anything I want with either alloy or temperature or both. As an example, I use one mold to cast for two very different 444 Marlin rifles. One needs a .431" bullet and the other a .433" bullet. To get that big bullet, I'm simply cast at 950° vs. 750°. That difference in temperature makes the difference in diameter as the aluminum blocks are going to respond through expansion. The bullets are out of round, but they size up very nice and round with a .433" sizer if they are pushed through within about 24 hours.

If you are going to size the bullets, I've found them to be quite malleable for the first 24 hour period and they tend to round out very well. I kind of view each new bullet sitting on the bench as a little living beast with a life span of about 7 days. Changes are taking place but I'm still trying to figure them out. That's about all I have to offer. I think I would shoot them and make sure its not something I would miss if I sent it back (done that too).

[Down South]

I did size several of them last night and they did come out well. At least that is my opinion of them so far. Hopefully I will have time to load some of them up in the next day or so and try them. I hope they work well. This was the first time that I have used the mould and I cast a full pot of them from my RCBS Pro pot. I’d hate to have to melt them all back down.
Thanks for the info.

[GabbyM]

Were the bullets frosted? Like when the mould is very hot.
When I'm running a six cavity Lee all by itself I use the wet cloth method to cool the spur plate. My 200 grain 44's come out very round. My preferred method is to use two moulds so one can be air cooling.

[Down South]

Yes, the Boolits were frosted a little. I was running around 825-850 Deg. I was using a wet sponge to cool the sprue plate and quickly cool the bottom of the mould before refill. I need to cast a few more at lower temps and check the boolit measurements again. I'm working on my boat at the moment but maybe I'll try later this evening.
I got some of the boolits out in the sunlight today. You can actually see the offset in the boolits. It's easy to hang the offset with a thumb nail.
I'm going to try casting at 750 W/no cooling and see what happens. I sized 20 or so more of the Boolits this morning and some of them are still .001" out of round after sizing.

[TAWILDCATT]

I wonder if it makes any difference how out of round as the bullet will be sized in the barrel.and cast are supposed to be couple thos over bore.my 45 acp has never been checked for size,I just lube and load.I used them in compitition for 30yrs.not saying I was top shooter,not with my eyes but I have my share of trophys. and I guess I am well over the hill as they say.[smilie=f: