I have fired about 1000 rounds through a CZ82 so far. When I first got it, it failed to feed about every third/fourth round. Eventually, I wound up with an education on CZ82 mags. There are many counterfeits out there, that fire the first 2-3 loads just fine, then begin to deteriorate. They average $15-$25 each, and are junk; it is difficult to determine just where they are made, but they are clearly inferior. The ads are misleading; they are sold as, "un-issued", "Czeck", "surplus", etc.
I discovered the $45 mags, at CZ-USA, are far superior to the counterfeits. They are equaled only by true surplus mags, which are distinguishable by an 'X' at the bottom side. Problem is, many of the 'X' mags are worn out; its luck of the draw, when you can find them.
Long story short, I now have three good mags: one surplus, and two CZ-USA, and cannot recall the last malfunction of any kind. I have not noticed any difference, wet with lube, or drier and dirty; I am not meticulous on keeling it clean, either. It eats JHPs all day, and loves Hornady CDs (when I can afford them), but has never liked JHPs.
I too, run an 18# spring, and agree, spring strength, within the available strengths' range, does not affect reliability. Stronger springs are a trade off: more muscle to rack the slide, but results in reduced recoil. If anything, heavier springs are easier on the gun, since the slide does not slam to the rear as hard.
