Mystery bullet found with metal detector

[Pulp]

My wife bought me a metal detector for Christmas. I went out to the 80 today to look for the .45-70 bullet that I killed this years deer with. Didn't find it, but I did find this:

It weighs 134.5 grains, and is .375-.380 across the base, depending on which way your measure.
There are no rifling marks, which makes me think a saboted muzzleloader bullet, but can't think of any in that caliber or weight. I suppose it could be a .40 or .45 that shed it jacket, therefore no rifling.

Any guesses?

 

[TwoForFlinching]

What the microstamp serial read?

 

[Okie4570]

Soft lead? How deep? Doesn't lead turn a whitish powdery gray when it oxidizes? It may not be that old.....................just guessing though.

 

[Pulp]

what the microstamp serial read?

Boooooo! Hissssss!

 

[11b1776]

I thought It was the real magic bullet, dang!

 

[Wiley Shanks]

Sabot?

 

[Pulp]

It wasn't very deep, less than two inches. I don't think it's old at all, because it hasn't oxidized. I just talked to a friend that shoots a .45 caliber muzzle loader, the bullets he uses are .40 caliber inside a sabot.

 

[green_machine2]

.410 slug?.. I dunno just a guess

 

[tntrex]

What the microstamp serial read?

lol