Looking for a few more mags for my GBX.
Not having much like with one specifically for the blaster, seems that another brand may fit…?
Let me know if you’ve had any luck 
SLR Mags. They have been mint in my two JGs (what these are, GBX was Twinnies name to be different to another retailer selling almost identical products, yes there was some animosity between the owners of respective businesses at the time!)