#25 probe o-ring is what was mentioned.
Check to see nothing obstructing the end of the barrel stick in a wooden dowel up front to see the end of barrel and LDC if applicable are not blocked. Remove LDC.
You can degass it for safety if you want or not as long as you DONT TOUCH #32x3 valve retaining screws.
Remove the stock. You need completely slide the safety out first by setting the safety middle way and use a tiny screwdriver to pry the spring/wire out you see touching the safety to push the safety detent completely out first while prying the spring. Reverse order after stock is back in when done. That wire goes in the notch of the safety to hold it in place.
Could be your hammer and or hammer spring binding or broken.
Remove #27, 28, 29. Don't strip the screws.
Remove barrel band and front sight screws or LDC threaded adapter screws and remove.
Remove upper barrel/breech assembly.
Remove #26 and 27. Remove endcap, hammer spring and hammer.
Remove trigger housing/ stock point retaining mounting screw #22 remove trigger housing assembly.
Check to see everything's OK run a rag through the rear tube wipe down hammer and spring and endcap then reinstall.
Check #23 and 24 if Transfer port may possibly have an obstruction and o-ring may be squashed and needs replacing.
Check #20 and 15 aren't bent.
Ace Hardware can get you going again with their o-ring drawer and even the hammer spring if that's broken or tired. You can try and stretch it out a little if it's tired. You can first remove the last trigger retaining screw and remove trigger housing assembly (must remove it don't damage the sear) and polish the hammer and the tube with a drill and wooden dowel and cut up old t-shirt rags with polishing compound to smoothen it up if you want just don't ruin the valve pin by going too much inside the tube measure max depth first. Degass for sure first if you are going to polish the inside of the tube with a drill-wooden dowel-rag-polishing compound and run clean rag before reassembly.
