Finally got a way to test hardness and went through some of my stash with the tester. A few things "known", and a few unknown.
One of the "known" things was supposed to be some linotype that I helped smelt down from actual printing letter blocks 35 years ago, 500 pounds worth at the time.
According to the chart I'm referencing, linotype is 22 BHN. This stuff tests at 28, so monotype BHN. Question is, would linotype age harden over 35 years like that? Or do I actually have monotype?
I'm mainly going to cast 50:50 WW/Pb for my purposes, just would like to know what this stuff is.
Here's a wealth of casting info.........
http://www.lasc.us/CastBulletNotes.htm
In a word yes, it's monotype. Especially if it was in "block" form initially. Linotype is either in strip form, as it was used in the linotype machine, pig form (typically in a long triangular cross section shape with a handling loop at one end), or ingot form of course if somebody previously melted it into ingots in which case you're on your own as to veracity of content).
Does the stuff have a purplish hue to it? Another tell-tale of monotype.
I have a couple Springfields that dote on a certain 170 grain spitzer-shaped bullet but only if it's hard as woodpecker lips and kept under 1700fps. The alloy of choice: 5 parts monotype/4 parts lead. A recent batch of them made of 5/4 lino/lead shot good too but not quite as well as the mono-alloy ones do. (When I say they dote on the bullet I'm saying 3/4MOA five shots/100 yards - not bad for a couple 90 year old Army rifles.) Would that this bullet performed as well with softer alloys that I prefer in general. I chalk it up to such bullet types propensity to slump in the rifling as they start their trip down the barrel - harder alloy and slower speeds mitigate that more often than not.
Purple hue, maybe in the right light, and freshly cast. Has a light haze of oxidation on it now from sitting so long.
I'm just gonna say it's monotype.
I shot some shortly after I got it in a .270 and with PB powder had phenomenal results. Haven't really fooled with it since.
I'm after hunting bullets so this stuff is too hard anyway straight up as it is.
Slumping can also be battled by casting full form bullets , RN nose that rides the bore sort of thing. Probably not telling you anything you don’t already know. Happy shooting!
F01
Yeah, I originally got the mold to concoct M1 Garand ammo, wanting the dead nuts reliability of feeding with spitzer bullets and lessened nose boo-boo's on bore riding RN and FN designs. Found that velocity/pressure sufficient to cycle the action was a bit too much for this particular bullet. Further experimentation in the bolt guns proved its worth.
Since then with the current M1 I've just stuck with jacketed 155 BT Palma's. One of only two rifles in my stash that I don't bother with at least messing around a little bit with cast.
Being in the printing industry over the past 45+ years, I used to handle both Linotype and Monotype. Linotype stands for Line of Type, while Monotype is usually found in the form of single characters. Linotype slugs are generally remelted, unless it's a job that is going to be reprinted several times. Eventually the casting and remelting process will deplete some of the tin and antimony and the alloy become softer, and it has to be rejuvenated using a tin/antimony pig. It's usually remelted in large batches and repoured into new pigs. In case anyone doesn't know what the hole at the end of the pig is for, it's to suspend the pig via a hook and chain that is mechanically lowered into the melting pot of the Linotype machine as the slugs are cast.
Monotype is much harder as it has a higher antimony content, monotype character are generally used on print jobs that would be used over a longer period of time when say just a date or time on the printed piece is going to change say from month to month. Being much harder, the type holds up to repeated use and stay sharp on the edges, whereas over time the Linotype character will deteriorate.
I was lucky enough to get my hands on a couple of hundred lbs. of lino back in the day when the other form of typesetting took over, I'm just setting on mine for a rainy day as I have plenty of COWW's and pure lead to cast all the bullets I'll need for some time to come.