Aged bullets

[Mainiac]

I cant really test this,because it would be a real bear to organize,but i swear older made cast bullets,shoot tighter then just poured.
Ive read of others seeing this as well.Can anybody explain this?

 

[Brad]

Age hardening. I like to give them a month or so to settle down.
They may change dimensions a little as well, as in grow in diameter a little.

 

[Tomme boy]

yep, my 223 bullets have to sit at least 2-3 months. My 350 legend bullets if i am just loading lite plinking loads it doesn't matter. but full jacketed speeds it needs at least 2 months to settle down.

 

[RicinYakima]

Like Brad said, stability. When I was match shooting, I cast bullets in December and January. Sized in May and first matches in June. FWIW

 

[richhodg66]

Has anyone ever done a systematic test to see if/how much bullets harden or expand over time? Does it vary a lot based on alloy?

 

[Rick]

It varies depending on the percentage of antimony. They will age harden for a little while then age soften over time.

 

[Winelover]

Sure alloy matters with regards to hardness.

Freshly, cast (air cooled) bullets don't change much, after three weeks. They've reached their hardness potential, for all practical purposes.

I have lubed and sized bullets that are 25-30 years old, sitting on shelves. Size only increased by .001, on average. Had no way to test hardness, way back then. However, testing them now with an LBT tester, they are still pretty much in the expected range of the current similar alloy.

 

[Rick]

Tin also plays a role, the higher the percentage of tin the less hardening will be achieved by quenching. Tin also effects the time curve in age softening. But it's still antimony that plays the important role in hardening and in growing over time in lead alloys.

 

[Rick]

As for age softening a heat treated Pb/Sb alloy it does occur but it is much slower than many people think. I discovered a box of RCBS 35 200 convection oven heat treated to 30 BHN under the bench, 10 years old, CWW+ 2% Sn. In 10 years they tested 26 BHN so yes, they age softened but not much and very slowly.

 

[RBHarter]

Copper ......boy howdy , there's a ride . While not systematic and only as accurate as my pencils fresh WQ were about 16 and over 2-6months crept up to the soft side of 18 . 5 yr out I had 22 and .002 . That was just incidental copper from lead tamper seals but I've had the same results with sorted plated range lead .

 

[CWLONGSHOT]

Yup learned long ago like wine and cheese... old bullets shoot better!

 

[Snakeoil]

If nothing else, it confirms how to pronounce his name.