Aries, did you have another person shoot your P345 and make sure that it is the gun and not you? Not trying to dump on you or disparage your shooting technique, but polymer framed guns are VERY non-forgiving of poor technique and limp wristing.
As an example, at the PD I work for and am a firearms instructor at, we issue the Beretta 92fs (alloy framed) if you want an issued gun or you can carry your own gun, within Dept guidelines. Only 1 guy carries a Beretta and, since the vast majority of our Dept carries privately owned Glocks, he thought about trying out a Glock. He ran the Beretta without any trouble at all, but consistently limp wristed the Glock. Needless to say, he went back to carrying the Beretta. His technique was adequate for the Beretta but bad for the Glock.
Poly framed guns flex during recoil, which is why most poly framed guns recoil less than metal framed guns. The flexing soaks up some of the recoil energy. The downside to poly framed guns is that they flex during firing, which soaks up some of the recoil energy, which makes them more prone to limp wristing than a metal framed gun of similar size and caliber. The flexing soaks up enough recoil energy that the gun needs to function that, with poor technique, you can limp wrist a poly framed gun but run a metal framed gun reasonably well.
If you haven't already done so, try having someone else shoot the P345 with the original recoil spring in place and see if it runs. If it doesn't run, call Ruger to get the P345 repaired. There should be no need to run a heavier recoil spring in the gun just to get it to function. It's either your technique or something is wrong with the gun.
Something else to look at is that sometimes auto pistols need a "break in" period to get them to run right. If the P345 is new, it may just need run some to get broken in. If the gun is used or has ~300+ rds through it, then "break in" shouldn't be an issue.
Bub
