I have been filling out my MG15 set-up.

The ground adapter, carry handle and MG34 bipod, are all still on the hunting list.
AA sites and ground use shoulder stock I have in the spare parts case.
I've been looking for one of the distinctive bellows style canvas shell catchers.
I've not ever seen one for sale, so was prepared to write it off - as impossible.

When this rusted relic part turned up on Ebay - it is the adapter for the Aircraft "steel sphere" type shell catcher.
With a little work I intend to convert it to use as the ground use, shell catcher.
I have looked at the Yugo canvas catchers and even the Polish canvas DTM shell catcher with a view to stealing the canvas and leather upper, but the canvas is not right - it has a modern look, and also they're far too small - the German MG15 canvas unfolded to about two feet in length.
So, I will likely commission a seamstress, that I have used before, to scratch sew one from old canvas. It won't be perfect but, better than nothing.

The adapter needed quite a lot of TLC, and will be getting quite a lot more, but, I think it will turn out OK - will post here as it progresses - they were finished in a really thick arsenal black enamel.
24 hours submerged in oil and the two locking springs came back to life, one may not even need replacing, isn't that fun, lol?
(It will fit in place, I didn't want to push it too hard in the photos as there was still gunk under the lips, offering resistance, that might have scratched the MG15 guide lips, more than they already are.)
I just drilled out the rivets, and have sourced some replacement ones for later, should be straight forward.
The black nastiness in side the adapter makes me think it was burned at some point. I personally like the fact it is being brought back from the dead.
(Apologies to anyone who thinks relics should be left as found, in some cases I agree, not in this one. )
*Posting pre-work, in the event someone has a better idea of how to replicate the bag.