I was told by a fellow at the Las Vegas Antique gun show that the small, three digit numbers on Lyman mould blocks indicate the number of cavities that have been cut with that particular cherry. One of the moulds I just checked has the number 980 on it. That seems like a lot of cavities to cut with one cherry. Was the fellow correct or am I being too skeptical?

JS

Would be like trying to cut 800 + plus chambers to the same demensions using the same chambering reamer.

I think the bullet numbers and the small manufacturing codes are getting mixed.

The 6 digit numbers (some early ones have only 4 ie 3118, later 311008) are the nominal diameter (311) followed by the design number (8/008), and are only on one of the blocks. The other numbers are on both blocks and are used to keep track of them as a pair throughout the manufacturing process, with no other known significance. Round balls are usually marked only with the diameter, ie 440.

Per the old Handbooks, the first three numbers were the nominal diameter (it got pretty “nominal” indeed during the late ‘50s-early ‘60s), and the next number (or two or three) was the top punch number for the Ideal/Lyman lubrisizer.

The letter codes following the mould numbers that have shown up in more modern moulds since the ‘70s are codes for the manufacturer of the cherries, which aren’t made in-house any more.

Once in a blue moon, a “U” will be seen after the mould number.  This denotes a special order “undersized” mould otherwise of the same design.  The few I’ve accumulated actually cast at closer to the nominal diameter than some of the unmarked ones.  Some will have a “S” denoting “short,” where the long-bullet cherry with many lube grooves was run in shallower to make a lighter bullet.  And sometimes “GP” or “HARVEY” or some other specialty designation will be stamped in small capitals on the mould.  These last are for the Lyman Great Plains rifle and the Harvey Prot-X-Bore bullet designs.

I have one or two with a large “R” stamped on them.  When the Leisure Group took over Lyman, they dumped a bunch of “Rejected” moulds on the market for cheep, with the letter stamped so they could never be returned under warranty.  Again, the couple I bought back then cast as good as any other mould, and better than some of them.

The smaller three numbers on the bottom of the blocks were assembly numbers, to keep the blocks matched as they went through the manufacturing process.

Vbull, a writeup on those cherries, how you got them, and the descriptions on the cards would make an interesting article for the SSR Journal, or the ARTCA Journal, or both.

This is a handy list: (You need to Login or Register to view media files and links)

Oneatatime, thanks for that= it'll be some time getting thru it all, but glad to have it so I can 'relearn' what I thought I had down pat. 
And, CW, that chart has been useful to me for a long time, it's a good one.

That’s interesting, vbull; about 1-1/2 year service life.  The Marlin flatnose was still a popular number, and still in the catalog, last I looked.  Despite the complaints I hear about Lyman mould diameters On Line, they seemed to have a very tight specification for cast diameters.  I wouldn’t find the final cast diameter unshootable, myself, for a nominal 0.457” diameter.  My Garrett carbine, with its undersized bore, would probably like it.  In the old days, it might be salable as a “U” designation.