12.7x108 ID help please

Headstamps top to bottom (i.e. HE first)
38 41
188 88
3 42

cartridge МДЗ-46 plant number 38, the city of Ulyanovsk 1941
2.cartridge БС
(sample 1972) is equipped with a factory number 188 city of Novosibirsk, 1988.
3.Likely Б-32,cartridge factory №3 of Ulyanovsk in 1942.

Top two bullets most likely,
lower maybe from .50BMG

If you read in Russian, I can give several references to these cartridges.

The bottom one is a duplex 1SL (1СЛ)

In a straight canal, not a notch.

The short projectile has a “V” cavity in it’s base, very much like the duplex 12.7 round.
ETA: Looks just like 12,7 1СЛ (9-А-4012) from this site, but with knurled grooves

I’ll take Russian references. I’ve found the papkin1 livejournal site to be good as well.

source of the cartridges says

N1 - MDZ-46
N2 - BS БC
N3 - BZF yellow brass plated БЗФ BZF-46
N4 - zinc BZF
N5 - BZT yellow brass
N6 - 1SL duplex

Патроны 12.7х108 v.02 (1).pdf (6.1 MB)