Cartridge weight variances

[kazzaerexys]

Those are non-jacketed rounds? Maybe it is a matter of some lead wearing off the bullets in routine administrative handling...

[DefensiveCarry.com]

[sideKahr]

Yes, they are lead semi wadcutter hollow points.

They are new, just out of the box. Appear identical.

[sideKahr]

I was passing a very accurate balance at work today, and on a whim I unloaded my .38 snubbie and weighed my cartridges ( I open in the morning, and no one was around).

I got the following weights in grams on 158 g LSWHP loads: 14.9977, 15.0425, 15.0527, 15.1541, 15.1632. This is a max weight difference of 0.1655 grams, or 1.1%. It's more than I expected.

Assuming the primers and cases are held to very close tolerances, the difference would have to be due to powder charge or bullet weight, either or which seems to me to be significant.

Has anyone else ever looked at this? Should I get my ammo from someone else?

[Shizzlemah]

That's about 2.5 grain variance I'd bet there was under 1 grain variance in the projectile, 0.1 variance in the powder charge, and possibly as much as 2 grain variance in the brass.

The brass will be the biggest contributor.

[HK Dan]

Oh, lead bullets can have huge variances in weight. I've cast bullets that looked fine and wound up over 7 grains apart (that was on a 275 grain bullet with a .30 caliber HP).

Casting alloys have 'eddies' and you can wind up with a heavier mix of lighter alloys in some than in others--you do get voids and folds from cold molds too. I weigh my hunting bullets and load them in similar weight groups, re-melting the outlyers.

Dan

[FallenPhoenix]

I would assume that the brass isn't held to extremely exacting tolerances, at least on the interior, so that's where the most variance could be found. That's just my extremely uninformed supposition though.