Did you try different bullet weights? I asked Massoud about jamming in two G-43s we had and he told me to go to a heavier, slower bullet. The lighter, faster bullets cycled the action too fast. No problems thereafter. Granted, my experience with the G26 is limited (I moved up to a G27 soon after and then barreled it to 357 Sig and never looked back). The friend who bought it reports no problems.
Maybe try another recoil spring?
Maybe try another recoil spring?
