The issue I've been having with the thumb, is due to a thumbs forward grip, and the thumb of my left hand, thats against the frame, hits the underside of the slide stop, forcing it up and locking the slide back. I dont seem to have the problem if I shoot with a different grip or one handed.
I've got about 400 rounds through mine now, and the second 200 (again, FMJ ball) werent as rosy as the first. Had a number of extraction failures, and a few light strike failures. The extraction failures were annoying in that the case was always still part way in the chamber, and its not a quick clear. The light strike failures arent real confidence inspiring either.
The P238 is the first SIG I've ever had troubles with (out of 17 others). I have two P230's in .380 that have been flawless since day one, but they are a basic SIG design. I cant help but wonder, even though SIG's name is on them, if this isnt just another poorly executed 1911 copy, with all the associated problems that come with them. I suppose time will tell, one way or the other. Until I'm comfortable with it working, its just an expensive toy.
I did contact SIG about the spring replacement issue. I was told by the rep that they should be replaced at 1000 round intervals, and thats why they sell them in a three pack, which of course, are currently unavailable and they dont back order.
I'm still trying to figure out the best way to carry this thing too (if that ever becomes a possibility). I dont have a problem with cocked and locked, as the safety is very heavy and secure, but that is also an issue, as its VERY loud when its swept off (as loud or louder than my M1's, M1A's, or AK's!), which I really dont like. Its much quieter and requires about the same effort, to just thumb cock the hammer. Just not to sure if I'm liking that mode.
I'm also wondering why the thumb safety doesnt lock the slide. For an old 1911 person, it adds a little confusion as to the state the gun is in, when the slide will open with the safety on.