Great work (as usual) oragus.
Some comments:
1)For the 251/21 I think you could make the protruding part of the 3 barrels the same length because the left and the right ones are equipped with longer cut-out flash hiders. Not sure this is the case for all versions tough.
2)I would lengthen the 75 Pak 40(L46?) a bit on the 251/22.
If you want to make other versions you still have the Czech OT-810s.
We wait for the 250s now
