Cost would be the driving factor.....weight being a byproduct. Injection molding is very cost effective. Trouble is, so is powdered metal....why they didn't go that route is beyond me. Aside from the stock the switch from plastic to metal would only ad a few ounces to the weight. The plastic is what kept me from buying one a few years back....mostly the magazine.Harrysigafoo said:I suspect cost and the desire to shave a few ounces off the advertized weight is the reason.