What are the dimensions of the rifle magazine pouches? i am curious if they are big enough to accommodate m1a/m14 7.62x51mm magazines.

I thought the same question. They are not big enough to fit 20rd or larger M1A, G3, FAL mags. The AK mag pouches fit them fine.

I know it’s intended for 7.62x39 but will 5.56 magazines fit well in it?

The Svd Dragunov takes a 10 rd magazine chambered in 7.62×54R. These mag pouches are too small to accommodate the 30 rd. AR mags. I also bought the Ak rig, and it came with 4 mag pouches. ..2 for ak 30 rd mags, and 2 that are the right size for ar 30 rd. mags. They hold 5 mags apiece, and are plastic lined, with no dividers.