The administration has been touting a requirement that private gun owners selling a few guns at shows be subject to the same background check requirements as commercial vendors, but has been unable to get the requirement through Congress. Glock has since rejected the idea since the company would have lost much of its autonomy. Dropping one ot two big gun lines wouldn't be as tough as it sounds, since handgun sales have been stagnant for years, with the market saturated and the best business done by small makers of either cheap or high-quality guns. Shops that sell a lot of new big-name handguns will likely sign on to the new restrictions, while shops that specialize in used merchandise and boutique manufacturers will take a pass. The biggest effect may well be on gun shows.
Private sales make up a small percentage of gun show business and so are, frankly, expendable.
Large-capacity magazine sales probably won't be seriously affected. Dealers who've never carried the things could readily knuckle-under without ticking off their customers. Well, it's an assault rifle in its fully automatic form, but those are strictly regulated already. I suspect that this provision was thrown in just so Justice Department geeks could drop the issue themselves. In response, some dealers will likely stop peddling suspect rifles, but others will use a strict definition of the term and remain unaffected.