Help with 9mm mag catch

[Great-Kazoo]

I built a 9mm AR with Spikes Tactical mag block and I am having trouble with the mags staying in the magwell, one good pull and out they come. Spikes website says to use one of their extended 9mm mag catches but I cannot find it on their web page, or any place else for that matter. Any other suggestion? The mags I am using are C-product.

I've opened up the mag catch area on c-products, synthetic mags , like pmags to get them to stay. The mag catch area of the mag, gets cut out allowing better seating. However before doing that ,put a piece of tape in the mag catch recess, then press the mag catch. If it indents the tape relieve the area. if not longer catch is needed.