They work pretty good in my 7.62 rifles. Never had any malfunctions with mine. I use them as range mags to save the wear and tear on my steelies.
I don't think I would want to depend on them in a serious situation since they don't have any steel reinforcements like the circle tens and military poly mags but they are quality mags for what they are.
In fact I wish tapco would make 5.56 mags to work in the SLR bulgy rifles