[Eugen]

OP, you got great advice from the replies above.

I'd also warn you not to try to replace the springs in your original mag. Unless you are very skilled or lucky, you are likely to cosmetically damage or perhaps ruin your original mag in the process. These mags are not your typical vintage mag that are generally friendly for mag spring replacement. There's a member on the forum named "G.T." that can replace the spring for you. He has fixed many for folks and he did a fine job on a mag for me.

So, just get a Mec-Gar mag and store your non-period correct, original mag. Lastly, I trust you properly cleaned and lubed your Erfurt before taking it to the range.