I have a problem with my model 27. I have only had it about 6 months and run about 800 rounds through it. with about 500 rounds through it the recoil spring jumped the lip on the guide rod and locked the weapon up completely. I took it to a gunsmith at a gunshow and he sold me an uncaptured rod and spring assembly( all steel) with a 20 lb spring which he said would be better for a 40 cal. before then I had no issues with it whatsoever. after replacing the spring assembly however I am now having a few failure to feeds with cheap wal-mart ammo ( federal fmj fn 180 grain ). I use 165 grain speer gold dots for my carry ammo and have had no problems with them but I have only run about 30 rounds of them through it. I also believe it is only one of the magazines I use that has this failure to feed issue. Is this a magazine problem? A too stiff recoil spring problem? A cheap flat nose ammo problem? Or something else? I love this gun but I am a little dissappointed and am a little concerned it is not functioning 100 percent if I have to trust my life to it.