My lightweight operator was good for about 300 as well....no matter how hard I tightened the op rod, it would always start to back off around 300 and malfunctions would start. Stovepipe's and ftc.
But up to that point it was a swiss watch.....and since I'm out of .45 for the time being, I've been eyeballing the armscor 2011 Hi cap in 9mm. 600 bucks and either some TLC or now there are some shops offering specific tune-up packages for guys building race guns out of em. Bout 200/bucks will get the trigger tightened up, ramp polished, barrel fit and 3 mags tuned....and reports are that they're workable before hand but after that they're incredible.