Alf... I've really pimped out the 22/45 MK IV... Striplin thumb rest and TankdeKross grips, just added a Volquartsen adjustable trigger, hammer, sear, which removes the magazine safety and drops the trigger pull down to about that of my SW M41...VQ adjustable recoil spring kit as it occasionally short stroked and didn't re-set the trigger... have had some light firing pin strikes on bulk pack Federal, so stuck a VQ firing pin in it yesterday... I had under cut the extractor so left the factory as it is working well... will try out the new firing pin Tuesday...
I'm running the Holosun 510c "jumbo tron" for a sight... looking forward to the cataract surgery next week... regards
Les