Home Forums Hunting & Shooting Ask The Gunwriters Do bullet jackets get brittle with age?

When I played with the 257 Ackley Improved, mid eighties, I used the Hornady 120 HP. It was a killer on crows (as one would imagine) and the small Texas deer. Hornady discontinued it, but I saw some other day online. After all this time, would the bullet jackets have become brittle? Maybe 40yrs isn't long enough...?

Believe it's actually the lead that breaks down and becomes brittle.

Would shoot a few into stuff and see how they perform before puttin'em into game.




GR

They haven't been discontinued all that long. I have a few boxes that I bought within the last 5-6 years or so.

I found some on GB, but they want $150 for 200. I like them ( as I "think" they also have a higher BC than the Corlokt 120) for all around stuff. I am trying to find out if they are still "good" after all this time ( I can handle 5-6 yrs, I have components from 32 yrs ago, ha.

Copper work hardens with age. A pliable roll of copper pipe will harden hanging in the shop. I’ve never thought about bullet jackets or solid copper bullets getting harder with age.

Thanks hanco- I should have said "bullet jackets" instead of implying "pure copper". But I moved on from the 120HP.. I am going to try the Hammer Bullets 97gr "Power Hammer" in this 25-06.

Pure copper and gilding metal (which is a solid solution of zinc in copper) don't become harder or more brittle simply as a result of age.

Age-hardening is a well-studied phenomenon. It occurs when a second phase is dissolved (by heating) and then, with time (and usually temperature) precipitates out of solution to pin dislocations in the crystal lattice, thereby reducing the ability of molecules to slip, which is seen on the macro level as increased hardness.

Work hardening is where cold working increases the density of dislocations, which again reduces the ability of molecules in the crystal lattice to slip.

Age hardening doesn't occur in pure copper or gilding metal because there's no metastable solution of a second phase to precipitate.

What can cause changes in physical properties with time is degradation, such as corrosion, but if your bullets have been well stored and show no obvious signs of corrosion they should be fine.

Just a guess, but I would think problems with jacket hardness/brittleness would show up in the trip down the barrel before terminal ballistics was an issue

These two are from a cow moose. These bullets are 200 grain Western Lubaloy bullets from an 8x56 Mannlicher Schoennauer. From what I can determine from the boxes the ammo is 75+ years old.

Two bullets doesn’t make an empirical test but it does give the impression they weren’t brittle.

Dang! A picture is worth....lol! Thats awesome mart. thanks for the comment and pics.