[Thor]

The Luger will last a long time as long as the ammo and the main spring are balanced. You can go the light route and if you have a light spring the action will not batter the frame/receiver too much, BUT you might have feeding problems or problems with it closing soidly and completely. If you got the hotter ammo route, a stouter mainspring is better, it will protect the action and metal more and close better. The problem is two fold IMO, most guns have shot a lot of ammo already and some have worn springs. You replace the spring and now the gun wont function with a standard loading. I favor the best idea is to find a loading you like and can afford, then adjust a new mainspring to JUST lock the action back everytime. A 36# new Wolff spring just about seems right to me for current loadings. If you are shooting the hotter stuff I would buy a 40# spring and see if it will still lock the toggle back, if it cant push the breech back, clip 1/2 coil and try again, until you reach a balance. But now if you go to standard ammo it will not work right. Find a load with a matching main spring and STICK WITH IT!.