AR-15 7.62x39mm block fits C-Products and ASC 30 round AR-15 magazines and will convert them to 10 rounds. The new design features a spring catch which will allow an easy attachment point to the spring. This prevents the block making noise and epoxy can be added at this point to make it permanent. Still allows opening the magazine for cleaning and parts replacement. (This is a modified AK block so it will have AK markings)