Do lead alloy bullets harden as they age?

Tasmanian Rebel · Post by **Tasmanian Rebel** » Wed Jul 14, 2004 8:06 pm

I have seen references occasionally that lead bullets harden as they age. Is it something to this or hogwash? I recently saw a post by a shooter who I have in the past thought knew what he was talking about say that a 30:1 alloy bullet will harden to a 20:1 if left on the shelf long enough. I can see maybe that the extreme outer layer may oxidize over time but this should be easy to wipe off. This hardening doesn't seem possible to me from a scientific standpoint- can anyone out there clear this up?

Trigger Dr · Post by **Trigger Dr** » Wed Jul 14, 2004 11:17 pm

Gee, I wish that I could give you a good answer, but..... My bulletts don't have the time to "AGE" as they go down the tube within5-6 days after being cast.
HOWEVER, I do have a box of internal primed, copper case 45/70 with 1882 dated head stamp, and they are just as soft as one of my fresh cast 30:1 slugs. Let's see....... Hmmmmm.... that would make them 124 years old. I don't think they hardened very much.
Trigger Dr Jim Milner
Time to brag a little. I shot in the West Sound Senior Games this last Saturday. took the bronze medal for third out of 34 . Just wish I could shoot BPCR as well as I play BILLIARDS.
Jim

loophole · Post by **loophole** » Thu Jul 15, 2004 7:52 am

I don't remember the details, but this phenomenon is discussed in the NRA cast bullet book. If memory serves, it occures with alloys containing antimony (and perhaps arsenic)--I think it is a characteristic of alloys containing wheelweights, and does not occur in lead/tin alloys.

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If at first you don't secede, try, try again.

Harlan Sage · Post by **Harlan Sage** » Thu Jul 15, 2004 8:00 am

If you want to know anything about lead/tin alloys contact the gentleman which I cannot remember his name right now, at Antimony Man at www.theantimonyman.com If he doesn't have the answer no one will. He explained to me that the alloy gets softer as it sets on the shelf and there will be very little difference from 20:1 to 30:1 after a few weeks on the shelf. The man is about 90 years young and full of knowledge.

Harlan

JAGG · Post by **JAGG** » Thu Jul 15, 2004 10:31 am

I think it takes about 2 weeks or there abouts for lead/ tin alloys and maybe a little longer for antimony alloys ! They also will age soften in time ! Like fruit you have to pick them to your likens ! JAGG

ironramrod · Post by **ironramrod** » Thu Jul 15, 2004 7:53 pm

Tas R.

I can't speak for lead:tin alloys, but the point of stability for wheel weight bullets appears to be about BHN=12-14 or so. Thus, wheel weight bullets that have been annealed to BHN=8 will gradually harden, but those that are heat treated to BHN=20-35 (depends on the method of heat treating) will gradually soften to approach stability in time. Storing wheel weight bullets at about 0 deg. F appears to stop the hardening/softening process completely until they are removed from the freezer and loaded. Generally speaking the higher the temperature where wheel weight bullets are stored the faster the change in BHN to approach stability.

The changes in softening/hardening may not have much impact on black powder rifles given the internal pressures that are produced. However, age softening can create some ugly pressure problems when smokeless powders are used, especially the faster burning powders (e.g. H4198, IMR 3031 and others).

Regards