I wouldn't mind upgrading the trigger on my B&T P26. From what I gather, Geissele doesn't work for some reason. Any recommendations?

One of the Geisselle works (other than the ACT and QMS) but one fellow on arf had to remove a small metal plate that keeps the hammer from striking plastic when the lower is removed and trigger pulled on a cocked hammer.

Found this info on a long B&T thread on AR15. Not my info but thought it might be helpful to you.

(KAC trigger in APC45 and Geissele SD-3G trigger in APC9)
Just have to remove a small metal plate in the lower that prevents the hammer from striking the polymer housing. This would only happen IF you let the hammer fall when the lower is seperated from the upper. This small piece of metal just slides right out.