Reinforced section on the bottom of the front pocket when you clip your folder to.(your knife) I know they have a dedicated pocket to use to hold your knife or whatever, but it's positioned a little behind the front pants pocket and the rear wallet pocket. Also, the front outer cellphone/magazine pocket needs to be a little deeper to better secure larger capacity magazines.
My 10 rd mags fit perfectly, but my 17 rd mags not so well. It will hold them, but you have to really pull the pocket flap over to secure the Velcro and it just barely secures. The mag pockets located inside the side cargo pockets do hold the 17 rd mags and also 19 rd mags. The outer phone/magazine pocket will hold two 10 rd mags easily, as do the inner pockets - holding 9 mm mags.
There are two inner pockets inside each side cargo pocket. They will each hold a standard 30 rd mag (Magpul or regular mil-spec metal) for an AR platform. I cannot speak for larger calibers. This goes for the pistol mag pockets as well, I carry 9 mm mags in them. These shorts seem to be very well made, they are comfortable. My rigger belts which are pretty wide, fit very nicely.
The only thing I will say is that I haven't really put these shorts through the paces with all the pockets loaded with mags. That's not a normal configuration for me. Depending on where I am going I may carry up to 2 pistol mags, but if I need to carry 4 AR magazines, I will kit up. and use a vest. I just say this because adding the extra weight of 4 AR mags and a couple pistol mags could stress the seams and stitching. These shorts would probably hold up to that kind of abuse, but I cant address that specifically. It's probably convenient for range use, but I wouldn't really want magazines slapping me on my outer knees when I'm running around.
My bottom line is that for the money I saved buying these vs. 5.11's which I own several of the taclite pants, these are a great buy. The 5.11 have the reinforced pockets that I like, but I don't like them so much to pay $10 more bucks. So for what I paid, I am completely satisfied and in fact bought another pair. One piece of advice: Be sure to turn your shorts inside out before washing them. Don't wash in hot water, do dry on high heat. Wash them in cold water, and dry on low. (same if you have waterproof/rip stop pants) Oh and don't use fabric softeners on them. Besides the obvious fact that they make your clothes smell, I think it can foul up the waterproofing qualities. Because if you've been in the field before, you know that "spring time fresh Downy" doesn't smell like any springtime I've ever deployed to.