HI GUYS.
I can confirm that today based on these reports, i fitted an extended Bertta / Mobil 12G choke to my Armsan A Challenge - firing slug for PSG diciplines. I wanted an open choke, so ordered cylinder.
Ordered from GMK who sent it that day, received next day. less than 24hrs later!. So thanks for the heads up info
https://www.gmk.co.uk/shop/12ga-+-50mm-hunting-mobilchoke-(ext)/11 ...excellent service. 01489 579999