Lead Shrinkage?

[korny351]

I've been reloading off and on for nearly 40 years. Decided to try and clean up some of my old stock. I found some old (30 years) Hornady 158gr. 38 cal. RNL bullets that I used to buy in bulk. Figured I'd just load them up for plinking ammo. As I was loading I noticed that some of them seemed to seat with almost no pressure whatsoever. Went back through what I had loaded and found some that would push back into the case with just finger pressure. Using my calipers I measured diameters from .3535 to .3575 with the bulk of them coming in at around .3550. I double checked the weight, just in case I had found some 9mm in error, but they came in at 158gr. Broke down the bad ammo I had found and just tossed the rest of the bullets.

Is it possible that over the years the lead has shrunk? Maybe due to cycles of heating and cooling? They had been stored either in an unheated basement in Chicago or in the garage or reloading shed in northern Ca.

I just don't remember having this issue when I was loading them back in the day. Or was Hornady's QC that bad and I was just oblivious?

[superdude]

don't throw them out! they're decaying into GOLD!

on a more serious note, i doubt they would shrink, but i can't base that on experience. it just seems unlikely. still, a good question.

[Wrightturn]

Have never seen cast bullets shrink. They do harden a bit with age but not that much. Soft alloy will shrink a bit more than high antimony but this happens when the bullets cool not with age.

Has anything else changed since the last time you loaded these bullets ?
Different brass or dies ? Most 9mm bullets will drop from the mold around .357-.358 and are sized down to .355-.356

[mikeg1005]

Did you measure them 30 years ago? Those exact bullets?

Maybe they were just off from the start.

MIke.

[sechott]

Throw them out? You can melt and recast them or give to someone who casts.

[korny351]

I'm pretty sure these are swaged lead bullets not cast. They appear to be the cheapest of the cheap. I'm using different dies now. The last time I used these bullets was probably 25 years ago using RCBS steel dies. I now have Lee carbide dies. Haven't had any problems with the Lee dies using other properly sized bullets. The problem is with the bullets. As I said, I'm measuring bullet diameters as low as .3535. It's not even like they've been crushed as the diameters are consistent when measured from different angles. Not really a big deal as I'm more than willing to toss them (less than 100 pieces). It just struck me as odd and I had never heard of this before.

[korny351]

Did you measure them 30 years ago? Those exact bullets?

Maybe they were just off from the start.

No I didn't measure them. I don't even think I had a caliper back then. My reloading practices were fairly primitive in those days.

Throw them out? You can melt and recast them or give to someone who casts.

Don't know any local casters.

[stillwater]

Over time, the moisture content of the lead decreases due to evaporation, causing the lead slug to shrink.

Methinks they didn't.

[supervel]

The problem I have found with old lead bullets is the lubricant drys out. Also brass cases become brittle. I would use them for tin can practice and throw away any cases that split. If you have to single load them in the gun so be it, it might improve your aim going slow like that and will improve your markmans ship whether they are accurate or not, because you will concentrate on you aim and trigger release. It worked for my bullet hoseing kid when I gave him one 22 shell at a time anyway.