Personally own an M4-2000. Leaning towards adding the SOCOM 556 as well down the road. SF cans are durable, reliable, the repeatable POI shift makes it a very nice prospect and SF comps/hiders are incredibly good. Gotten to run a couple SF cans at various events so my experience is only good for around 150 rounds.
Haven't run the KAC QD I'm afraid. Can tell you running an AAC tuning fork gets a bit annoying when I don't have the can on...so an SF comp would be a welcome addition.
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