[Thor]

Try the 36 pound one first. If you are shooting standard pressure ammo, that one might even be too strong. Artillery Lugers have more mass to move during recoil and many of the ones I have worked on have had the spring pressure weakened intentionally to fire mild ammo. The trick here is to watch the ejection pattern. If the casings come dribbling out, then the set up for that ammo is maybe too strong a spring and you might even have failures to feed and eject. Have some one watch the empties and if they are rising 4-8 feet in the air during firing you are probably about right, Also check that each round is pushing the breechblock back far enough to lock it back. Once you have the casing ejecting right and the breech locking, you are there FOR THAT AMMO. Change power of ammunition and you might be starting over. If the ejection is too hard, you are over hammering the rear toggle, the frame cam ramps and the ejector so you dont want to go to that extreme.