[HKneo]

Can anybody tell me why my old g21 mags malfunction after I put the Kriss super V mag extension and does not on the new generation g21 mags?. Is
it due to the changes in their mag follower or the mag extension were designed to work only with the new gen g21 mags?.

[JR]

Thats what I would go with.
You might want to contact Kriss direct and get the whole story. BTW: Be sure to keep us in the loop!