Can you ID these .401 Slugs

[SW CQB 45]

they were my dads and he passed in 05.

I found them in a whip cream tub marked Win 155 grain TC 10mm .401

I have 249 of them and was going to try and push them but I cannot find any data on the net.

Did Winchester once make a 155 gr TC jacketed slug?

the back or bottom of the slug is open or exposed lead but these are copper jacketed. they would have been purchased prior to 05.

I guess I need to weigh one to confirm but my dad was a stickler on accuracy, so these have to be marked correct but I will double check on the scale this week.

[Ivan the Butcher]

Hornady's reloading manual has loads for 155's in both 10mm and 40 S&W.