I worry about that front sight too, but I've run >250 rounds through my sub2000 in a session and it only needed the feed-ramp wiped off (finger, nothing fancy) a few times, it runs dirty just fine with cheap steel-case ammo and Glock mags (the Korean mags were another story, I should tear them down and de-burr them before pointing the finger of accusation, though)
I don't know, while I'd grab my M1 carbine for a real SHTF type event, I'd probably toss the sub2000 in the bag with some mags and some ammo too ... it doesn't weigh anything and I think having a PCC is a good thing.
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Girodin, got a source for that better front sight?