Mystery Slug?

[Slugster]

While changing targets at Knob Creek Range a few weeks after the machinegun shoot... 30 years ago, I picked up a fired bullet that ended up in my junk drawer. Pulled it out yesterday and find it to be a real oddity.
Description:
1.852" in length
Spitzer Boat tail
.428 diameter
Looks to be solid steel
Hard enough that I have used it as a punch

Anybody know what this is?

[kerplode]

It's likely the hardened tool-steel core of an M2 AP 50-cal projectile

[gwpercle]

It's likely the hardened tool-steel core of an M2 AP 50-cal projectile

The hardened steel AP core will totally separate from the rest of the projectile , which looks like a normal ball round of ammo . The lead - jacket outer covering gives the rifling something to grip into ... the hard tungsten steel "inner bullet" looks just like a boat tail projectile only undersized .

30 cal AP 30-06 have (had) the same kind of hardened steel inner projectiles , I discovered this when cutting off the tips of some US GI AP rounds , I was making flat points to hunt deer with and found these inner steel bullets ... my file wouldn't cut it ... so that's why these rounds had black painted tips ...black = armor piercing ammo ... it would shoot right through a deer and three pine trees ... lotsa penetration !!!
Gary