Length of Mainspring
 

I have a "shooter" (DWM on toggle) that probably is an East German rework, perhaps early 20s. It is caliber 9mm.

I have completely stripped the piece, so I can remove all the old "brown" crud and relube it with a modern gun lubricant.

I'm curious if the mainspring is original, and the proper one for the 9mm caliber. When removed from the gun, and in a completely relaxed mode the mainspring measures 3.5 inches in length, and has approximately 22 coils.

Does this appear to be the proper mainspring for this gun?

You have a recoil spring appropriate to a later Luger (like those made by Mauser).

The earlier coiled springs associated with the .30 Luger and the 9mm Imperial / Weimar era Lugers had fewer coils.

This relates somewhat to the ballistic characteristics of the ammunition of the eras.

Get some 115gn standard velocity 9mm ammo (Winchester white box, etc...) and give it a try. Use a firm handhold and observe how it cycles. Watch the area on the receiver right at the back where the rear toggle impacts it.

Marc