I will make a confession, its me who is the guilty one who actually make these gains and the plastic type gain for the 17 clockwork bomb fuze. The original ones are very expensive and i notice that originals are sectioned for display, which is a shame. So i made these so collectors can either section them or fill the gap in their collection until originals turn up. The bottoms which i have seen on originals do vary from a slight concave to a flat bottom. As these are cast from an original they are very difficult to do to get a neat finish on the bottom as this is the end i pour the plastic in. I then finish them off in a lathe, i suppose they could be polished a bit but not sure how to get good results, but this would be best to leave it in this finish so collectors can at least tell the difference to an original, which new collectors could get ripped off paying for a replica at original prices. The colour i eventually mastered, the one Skull181 has are near exact the Bakelite colour to the originals i have, the originals do vary slightly in colour to each other.
By the way i also make other replica bits that help fill the gaps of hard to come by originals until the original turns up, which i see no harm in doing as that certain piece could take years to find. Ben Fjordhouse was looking for a sticky bomb leaver. An original in good non relic condition will eventually turn up but it could take some time, even years to find a mint one but a good quality replica made to exact standards would fill the gap until an mint original is found, this all depends on the ethics of a collector.
I also make other things.
RM43 charges.
S-MiZ 44 igniters.
Keeper rings for the Pazerknacker.
rare 10kg charge.
ES.MiZ40 bracket and other plastic related bits
S-Mine bits top screw sets, late war, early war, Smine 35 and 44.
Shu mines and 200gm charges.
Pot mines and buckigniters etc.
As you see most items are really hard to find or are in a delicate state in their original condition ie Buck igniters etc. Reenactors or Living historians who display such items would rather get a replica damaged than the rare original. How many mine collectors who have original S-MiZ44 igniters screwed in the top of their original S-mine44, I only know of one person.
Personally i have no problem with copy parts, as originals get harder to come by but saying that 5000 MP44 assault rifles turn up in Syria not that long ago. To cap it all i hope i am doing a bit of a service to help collectors out like myself and many thanks for the comments on my wares.