Mountain Molds

When you drop WW bullets out of the mold, they air-cool fast enough to harden slightly. Small bullets will air-cool faster than big bullets. If you have a fan blowing on your casting area, it will speed cooling and increase hardness. One caster was getting 16+ BHN on his air-cooled bullets while using a cooling fan, but if he turned the fan off, the BHN dropped several points.

I used BaBore's hardness tester to measure a few wheelweight bullets. These slugs were air-cooled and had been sitting on my desk for a couple of weeks.

280 gr air-cooled WW -- 13 BHN

418 gr. air-cooled WW -- 12 BHN

Then some of these same slugs were baked in the oven at 430°. After one hour, the oven was shut off, but the slugs were left in the oven so they would cool very slowly. The idea was to anneal the metal, undoing any heat treatment.

oven-annealed WW -- 9 BHN

9 BHN is exactly what the Lyman handbook lists for WW.

Inevitably, I heat treat all my wheelweight bullets whether they need it or not, but if you did want a soft wheelweight bullet for reliable obturation -- like for BPCR or for CAS -- oven-annealing may be worthwhile.

I'm new at this site and what do I find the first time I look, this info. I've got a large supply of wheel weights and a source that gets me a 5 gal pails worth every month or so (mtngun: "I am way jealous"). I had been wondering if you can soften wheel weights without mixing with lead, I want to get a BPCR rifle but I didn't want to go through the hassel or expense of getting pure lead or a mix. If they soften to around 9 BHN that should be just about right for the BPCR shooting I'm going to start doing. Thanks a million for the info. I tried getting an answer on the Greybeard site but the guys went off on some tangent and never did give me a clue as to if you could soften wheel weights or not. Thanks again.

-- Peter aka pistolfan


pistol fan, another source of soft alloy that you probably already know about -- the tape-on wheelweights are usually quite a bit softer than clip-on wheelweight. At least that's been my experience. I'll try to do some BHN tests on tape-on weights in the next few days and post the results.

FWIW,

Here are some BHN numbers for the different types of Tape-on-WW I have on hand.These were checked with a Cabintree Tester
#1-Tape-A-Weight stamped on lead,BHN -avg- 8.5
#2-1/4 oz-7gm stamped on lead, BHN- avg 10.0
#3-1/2 oz-14gm stamped on lead,BHN-avg 8.5
#4-1/4 oz TAW.7gm stamped on lead,BHN-avg 9.25

I assume TAW stands for Tape-A-Weight.

I have about 50 lbs of tape weights on hand ,they come with all the WW I get .I have never used the tape on weights,generally to soft for my application OR thats what I think.The WW around here BHN at 14 after I melt down a 40-60 LB batch and pour into ingots.

Sean

My tape-on wheelweights seem to be the same as Sean's.

It looks like air-cooled tape-on would be an acceptable substitute for 20:1 alloy, and the price is right.

I didn't try annealing the tape-on slugs. I don't know if it age hardens or not, but it may. If I had to guess, I'd say it is alloyed with around 1/2% antimony and maybe a little arsenic. This was tested about 6 hours after casting.

[table]
[mrow] alloy [col] density (grain/in[sup]3)[/sup] [col]BHN
[row] air-cooled clip-on WW [col] 2794 [col] 12 - 14
[row] 20:1 [col] 2775 [col] 9
[row] air-cooled tape-on WW [col] 2841 [col] 9
[row] 30:1 [col] 2838 [col] 4
[row] pure lead [col] 2854 [col] 4
[/table]