List of Lyman / Ideal Undersize "U" Molds

[ohland]

I pulled this list from the '59 Belding and Mull Hand Book.

There is a much more detailed list in the Lyman '58 Handbook of Cast Bullets. My ultimate intent is to get the normal cast diameter and undersize diameters added to my list.

From my dim memories, the U molds are .001 over nominal. Remember that manufacturing tolerances may make any mould to be something you don't expect...

From the Belding and Mull Handbook #38, 1959, page 48.

“Generally, bullet moulds are made to cast bullets larger than standard to permit sizing to the diameter most commonly used in a given arm. While there are exceptions, most cast bullets are sized .002” to .003” larger than groove diameter. Some shooters prefer to use cast bullets sized to groove diameter and some designs are furnished to permit this. They are designated as “U” moulds. The following are available as “U” Moulds:”


U225450 U311316 U321297 U358242
U225438 U311334 U356402 U358246
U225415 U311359 U357446 U358250
U257418 U311329 U358345 U375449
U257388 U311291 U358425 U42798
U257312 U311299 U358416 U429215
U280412 U311278 U358432 U429244
U280468 U311241 U358429 U452423
U287346 U311413 U358311 U452460
U3118 U311466 U358495 U452374
U311467 U311284 U358271 U454190
U457124



:coffeecom

[Le Loup Solitaire]

Thanx for the leg work and compilation of the U molds that Lyman once made. Lists like that save folks a lot of time and burrowing to gather information. The U marked molds were issued at a time when Lyman was already trying to figure out how to make cherry cutters last. Only instead of simply running cherries to the point of creating undersize molds, as they do now, they started with oversize cherries which of course produced oversize molds and ran them until they reached a point where they could be termed U or undersized....compared to what they were to start with. As a result Lyman earned the temporary nickname of "King of the Oversize". It was still preferable to the current situation where you have bullets that hop and skip down the bore and shoot like poop. Nevertheless that era in Lyman's history gave us a wide and more prolific selection of cast bullets most of which has been sadly discontinued. The "U's" were an asset to many shooters. Thanx again for the list. LLS

[Freischütz]

These days the "U" designation appears to automatically apply to many Lyman moulds.

[Bret4207]

It was my understanding that any Lyman mould could be ordered undersized. I'm also a little confused as to why B+M would have a list of Lymans moulds. I'm further confused because IME both the "U" and "S" moulds could be undersized. Maybe you could expand on this a little and help me understand what it is you think they did?

[ohland]

It was my understanding that any Lyman mould could be ordered undersized. I'm also a little confused as to why B+M would have a list of Lymans moulds. I'm further confused because IME both the "U" and "S" moulds could be undersized. Maybe you could expand on this a little and help me understand what it is you think they did?

If you have a U marked mould that is not in the list, post it and I'll add it.

The list was quoted from the "Belding and Mull Hand Book" subtitled "Hand Loading Ammunition", it is not a B+M catalog. Think of the Lyman Cast Bullet Handbook, 4th ed. where Lyman lists Lyman, SAECO, and RCBS moulds.

At this point, U means to me to be .001" over nominal. Due to tolerances, I'd say it depends.

S does mean Short. Supposedly. Not seen anything yet which also includes a diameter as well.

I'm just standing on the shoulders of giants.

[Bret4207]

It has been stated in some material that the "S" moulds were "Special" which would cover short, long, skinny and extra fat! Have you contacted Floodgate or someone like that over the Antique Reloading Tools site? I thought most of this work had been done already.

ETA- huh. Seems like the ARTCA forum is gone. I'll try contacting Floodgate.

[ohland]

Here it is.

[floodgate]

"U" meant "undersize" (NOT 0.001" oversize!); in many cases the "U" bullets used a specially-cut cherry, but no doubt worn, re-sharpened cherries were als put to use for this purpose. One bullet - I believe it was the Squibb 169-gr. gas-check spitzer #311413 was also available at one time in the '50's as #311413 ES (for "extra small"). The "S" designation could be used for many purposes: "small" - to indicate a .357" / .358" .38 Spl. version of a bullet normally sized .361" for the old .38 S&W; "short", for a shortened version of a standard bullet (I once saw an "S" version of the Squibb bullet, "short-cherried" to eliminate the gas check and one grease groove); and - probably for "special" - to indicate a custom modification to a standard mould. And yes, the size variations are quite overwhelmed by the effects we see from new vs. worn cherries, cherries made by outside contractors (indicated by a two-lwetter code following the mould number), and by the individual user's casting techniques, alloy mixes, casting temperatures, etc., etc.

floodgate

[Bret4207]

Thanks Doug, that's about the way I remembered it.

Ohland- I think you hit the problem in post #5- tolerances. Lymans "nominal" diameter appears to have been something of a krap shoot, even back in the good old days. I'm not sure you're going to be able to say definitively what diameter they dropped.

[ohland]

It has been stated in some material that the "S" moulds were "Special" which would cover short, long, skinny and extra fat!

As I was walking to and fro in the internet (thanxs, Al Gore!) I found the Lyman Mold Number FAQ on Cast Pics.
http://www.castpics.net/subsite2/Classics/Lyman%20Mold%20Number%20FAQ.pdf

"Other letters preceding or following the bullet number can be an identifier for a particular cherry of several for a specific bullet (like #311291AV), or can indicate "undersized": U- or -ES: "extra-small"; or, sometimes -S for "small"; "S" is also occasionally used for "short", where a shorter version of a particular bullet is made by inserting the cherry less deeply) ."

So in the specific case of the 280468, it has been seen with S or L. My S has one less driving band than the L.

Hmm, so a U280468S would be a .281=ish diameter short bullet. Numbers hurt! Need alcohol! Must... stop... thinking... gaah!!!

:veryconfu

[Bret4207]

I think that's supposed to be www.antiquereloadingtools.com

[scrapcan]

oops fat fingered that one. fixed it above. Thanks Bret.