I think 2 things are going to happen. First, we aren't going to see MANY high cap mags on the market right away except maybe the ones marked for LE only. I say that because the ATF isn't going to approve any import permits until after it expires, so it'll be at least a month probably before any made out of the US get approval to even come in. Ones made in the US will be seen sooner. HOWEVER, new guns with 10-rd mags will either have the guns replaced, discounted a lot for quick sell, or the ones with full cap mags won't be out until the ones with 10-rds are mostly gone. I say that because those guys aren't gonna beat down the door to make their own product "unsaleable" at the first opportunity.
The second thing that is going to happen, I think, is that we are going to see 10-rd mages in guns that would normmy hold ~15rds go fgor sale for dirt cheap. I don't know HOW cheap, but if I see Sig 228 10-rd mags, for example only, for less than $10 each somewhere, I promise you that I'll buy a couple dozen. I like full capacity mags, but CHEAP factory mags that only hold 10-rds still have a lot of uses and ius MUCH better than a sharp stick in the eye.
KJ