Unfortunately, for me, being a resident of the PRW ( Peoples Republic of Washington ) with our 10 round magazine ban, I can’t purchase one since they come with 20 round magazines ( as described in their promotional card which is posted on the AR-15 website and attached along with a photo ). It’s likely the original Rock magazines would also fit ( I got 5 before the ban went into effect ) but being longer it kind of defeats the whole concept of being compact. 
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