I have had a few Storm Lake 10mm barrels. They were drop in with no fitting required, accuracy was as good as stock.
You can tell if it needs fitting as it won't go into battery when slid into the slide, the barrel hood won't fit in the cut out of the slide. I had to fit one so called drop in KKM barrel, it didn't take much at all to get it locking up cleanly, fine stone stuff.
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