Reading Mold Numbers

[Pitmaster]

I've been trying to figure out how to read and understand mold numbers on molds. Can anyone link me to a source that explains what the numbers mean? I think I've figured out that the diamter of the bullet is what is important. I keep looking for caliber #'s and then get lost.

Thanks,

[floodgate]

Pitmaster:

Just about every mould maker has a different "code". Lyman/Ideal moulds are marked with three digits indicating the "size-to" diameter followed by three more that are just a more-or-less chronological sequence number (though these have in some cases been re-used from discontinued moulds); another group of numbers appearing on both blocks are a "match number" to keep the pair together. Some makers use a pretty logical diameter + weight number; some others, like Hensley & Gibbs just use a sequence number, and you have to have a chart to decode them - some of these are posted on CASTPICS. One weird one was used on the old Modern-Bond moulds (which originated the separate blocks and interchangeable handles back in the '20's, soon copied by Lyman). They used, for example, "D-311-955", meaning the fourth (A, B, C, D, ..get it? ) design in 0.311" diameter (with a new sequence for each caliber), 0.955" long (150 grs.); a double-cavity mould I have with two different weights/lengths of the same bullet is stamped "D-311-955-1145", with 150- and 180-gr. bullets, the latter 1.145"long.

It would be nice if they were all the same and logical, but.....

Floodgate

EDIT - PS: Lee's code is perhaps the most useful, as it gives diameter, weight and an indication of the nose profile, with a prefix indcating a tumble-lube ("TL...") or gas-check ("C...") design. (No prefix indicates a plain base bullet with standard grease grooves.)