Stumbled across this thread as I was having similar problems myself.
TM P226 (getting on a bit) barely able to shoot half a mag and failing to lock back when empty.
Followed the advice above stripped and cleaned it to within an inch of its life. Still not cycling properly.
What I then...
I recently purchased a second hand RIF via this forum, the initial discussions went fine and despite the fact that the vendor wanted paid via bank transfer I felt confident enough to go ahead with the transaction.
I promptly received the gun as promised (poorly packaged) only to discover there...