I had bought a 50pack of Cproducts mags just after the election for AR-15s and 10 LR-308 mags. Ironically I didn't have a AR at the time(A lot of guns just no ARs) as I was waiting for backorders. Have 3 ARs now and sold every one of those, which I came out pretty good on. The C-products ones certainly work (I actually only opened and used one of them), 100% reliable for me. Pmags just look cool and can buy them cheap enough with a C&R/Dealer account ~$12 I just went that route. Dumped the LR-308s while I could, as pmags will be out soon for half price. I think you need 20rd mags for shooting from a bench, and should have what your rifle case will hold or what you can reasonably carry, that number is probably 5-7 magazines for most people. Depending on the gun I only have 2-5 mags each now, so need a buy a few more.