Water quenching and hardness

[mefunkymxw]

Hey all, I just got my lee lead hardness tester in the mail the other day and I tested both my WW ingots and my water quenched boolits (240 gr SWC .430"), and the hardness is pretty different.

the straight WW ingots which were air cooled have a hardness of about 15-16, and my water quenched .44s seem to be reading between 22-23... this is almost a 50% increase in hardness after water quenching. Do these numbers historically agree with any of yours??? it seems to me like that is a pretty huge fluctuation given water quenching is the only difference (same alloy).

[sqlbullet]

That is pretty common. My son and I did a number of quenching tests together a few years back for the science fair. The base alloy would air cool to around 11-12. Cast from a 750° pot and quenched right on the edge of a sprue smear we were seeing above 30 BHN. This was an average of 10 slugs.

Chart can be seen here: http://fellingfamily.net/isolead/. See entries 13 and 14 for a straight air-cooled vs quenched comparison with no other variables (that are within our control). Entries 1&2 and 7&8 are similar comparisons at lower casting temps.

[mefunkymxw]

Thanks for the reply... good info in your table. Im loading some 44s with gas checks but am still testing hardness and trying to stay under the max pressures recommended in the testing kit since these are my first lot of ww cast boolits.

[Bigslug]

I had my air-cooled range scrap ingots test at 9.75 and water quench boolits from the same stuff end up at about (IIRC) 14-16.

You've pretty obviously got a higher tin or antimony content, which will have a greater effect. I'd say you're OK just air cooling that alloy for a .44.

Now if I only had a water-cooled firearm to go with the water-cooled boolits. . .

[GabbyM]

Your hardness is more than likely reading to high.
AC WW don't generally come in over 12 BHN. But then you may have a really hard batch of WW.
Water dropped from the mold WW boolits will be very hard. 22 BHN would be about right there. I prefer 50/50 blend with ww - pure Pb with a littel tin. Bullets won't shatter on bone and they are plenty hard still. plus I seam to always have more pure than ww.

In my experience. If you water drop those big 44's. You better get them though a size die the same day or you'll never get them pushed through if they have much diameter to swag down. After they harden up. Also gas check shanks may swell up with the rest of the boolit so at least push on the checks while you still can. It's a case by case study but a hard lesson if you have a pile of boolits you can't finish. Been there.

[mefunkymxw]

gabby, yes im sizing generally within a few hours of dropping them... i seat the gas checks at the same time in the sizer. i have some pics of the lead through the process, i will try to post them next.

[mefunkymxw]

[mefunkymxw]

this is my first lot of any self-cast boolits... i did 100, i put 22.0 grains of H110 under the 240 grain cast WW boolits you see above... winchester large pistol primers, generally winchester cases though i did have a few federal in there as well. I will have to find a place to test these out of my S&W 629 classic and my winchester miroku 1892 repro.

the ingot is obviously straight WW alloy, came in at a 15-16 BHN, the next is a water dropped unsized boolit, came in at 22-23 BHN, next is just an unsized boolit, next is a sized/lubed/gas checked boolit, finally we have the finished product.

[454PB]

15 BHN is very hard for ACWW.

Don't get too hung up on those recommended pressure limits. I've used gas checked ACWW boolits in my .454 Casulls at 50K psi and they work just fine.

[mefunkymxw]

good to know 454, i didnt think it would be a big issue with the gas checks, but wanted to hear that from the horses' mouths as it were.

[Calamity Jake]

Your test points are to close together there needs to be at least ¼" between test points to have any real accuracy.

Jest letting you know.

[mefunkymxw]

good call calamity, i should have realized that the deflection from one might affect the reading on another... the test points on the ingots were somewhat spread so i think those are ok... and the ones on the WD boolit were pretty consistent from first to last so I am not very worried, I will actually file down the opposite side tonight and test that though, just to make double dog sure.

I did test the very top of the nose on that one as well and got the same reading.

[williamwaco]

NOW.

Let's extend you education.

Set a half dozen of those bullets aside 6 of each WC and AC and test them again in six weeks.

[mefunkymxw]

the ingot may have been sitting around for about 4 weeks in my cold garage... i let them heat up to room temp before i tested.

[huntinlever]

Your hardness is more than likely reading to high.
AC WW don't generally come in over 12 BHN. But then you may have a really hard batch of WW.
Water dropped from the mold WW boolits will be very hard. 22 BHN would be about right there. I prefer 50/50 blend with ww - pure Pb with a littel tin. Bullets won't shatter on bone and they are plenty hard still. plus I seam to always have more pure than ww.

Sorry to resurrect, just trying to nail down what to generally expect as a one-month aged 50:50 w/ 1% added Sn and water dropped - not heat treated (and I know this adds inconsistency, so a general figure if possible) should be in BHN.

Edit: Runfive, if you're around, I see from here you project about 15 BHN with a water drop. How about the above, with this little Sn sweetener?

One more wrinkle - varying opinions on sizing after dropping. My working premise is that doing it within a day mitigates against the work-softening effect; that the hardening continues for days and weeks afterwards so the softening impact is minimal. On target?

[454PB]

The quicker they are sized, the better. I do mine within hours of casting.

[huntinlever]

Thanks 454Pb. Makes sense.

[GabbyM]

The quicker they are sized, the better. I do mine within hours of casting.

DITTO:

If you will be sizing more than .001' or so you'd better size them before they get hard or you'll be in for a tough time. I've had to place bullets back in an oven to soften them because I couldn't' get .002" sized on a .30 caliber rifle bullet. Most desirable situation is a mold that drops nice round bullets within a few ten thousandths of an inch of your final size. Then you don’t have to worry much about softening the bands or getting them pushed through the size die. But life isn’t always simple. I like enough size action to get the gas check the same size as the bullet body. I have had 30--30 bullets sized with a .310" die. Where the check was larger than bullet. Case neck was expanded by the check leaving loose a bullet. So I set up a .309" die in a Lyman 4500 to just size only deep enough to reduce the check and a bit of the bottom band. 30-30 necks are thin so even if you annealed your gas checks the necks probably would expand before you sized checks with necks. I'd never intentionally load rounds depending upon sizing checks with the cases anyway. Annealing gas checks is usually done if you are getting spring back after bullet sizing causing checks to spring back larger than bullet body.

My last mold from just a couple weeks ago. 30 caliber 220 grain flat nose specked at .310" from Accurate Molds. For my 30-06 I can size these either .310" or .311". Whichever is closer to dropped bullet size. Alloy plan for these is to have between .003 to .008% (Cu) copper, 1.5 to 2% (Sn) tin and about 3% (Sb) antimony. Heat treated or dropped from the mold. In my limited past experience. Copper makes bullets far more difficult to push through a sizing press. So I ordered this mold planning to size them close to as cast diameter. My belief is it's easier to get a bullet started straight down the die also. You don't deform your nose or base either.

I’ve tried sizing gas check rifle bullets before oven heat treating. Trick there is to not deform the gas check shank. Nose first in a Star always mushroomed the ones I tried. So I used a Lyman with nose punch. Some people go ahead and seat the gas check. Suppose that should work as the check should be totally water tight. Process you chose will be dependent upon your equipment and several variables. Just have to figure out a process that works.

While it's nice to have everything fitting just the way we like it. Also sort of silly to frustrate yourself searching for nirvana.

[fredj338]

Pretty much what I get on my CabinTree.