I have an old Turkish Mauser that I shoot 50's Yugoslavian 8mm ammo in, with quite a few misfires. The headspace is good; I'm pretty sure it's the ammo. I was told to get a Wolff extra power spring, but I don't know what weight is necessary. The heaviest they make is 30lbs. I'm tempted to get it just to make sure, but didn't know if there is any drawback to the spring being too heavy.