find it my reloading room again: anyone ever seeing 1,5" Minie lead bullets before?

there is a guy with a muzzle loader canon made from a german WW 2 3,7cm Flak barrel.
the flak barrel served 45 years as a fencepost when the war ended. it was found good enough to go back in service again and because it was allready rifled a big Minie Bullet mould was made.
in the end the target was disapointing and most of the smooth bore muzzle loader with wrapped lead balls shot much better. the Minie bullet is sometimes very tricky, dont like high powder loads.

37x94R Hotchkiss "Pom- Pom" shell, 35 Rem for comparison, 3,7cm Minie bullet, 50mm lead round Ball

when the 2 bore is not enough such a 3,7cm flak barrel chambered for the 37x94R Pom-Pom case may be the next step

I know another rifled muzzle loading canon but with a 76,2mm or 3" barrel in a napolenic reeanactor battery. very funny story: when the russian leave germany in 1994 they put all the stuff on trains. one full loaded train was standing on a railway area over nigth to go back to russia next morning. they also had load an WW 2 T 34 tank on the train that was standing as a memorial before.
one of the railway mechanic's take his welding torch this night and cut the barrel from the T 34 standing on the waggon. next morning the train leave germany and this man is a member of the battery today.