I reassembled it a few times but still no luck. It has a ball bearing, not sure if correct but I like the idea of the TnT kit so definitely on the cards.
Had the hammer out earlier and can’t see any issues. I made an effort of taking every piece out, cleaned, regreased and reassembled. Gave it a test and it got through about 25 bb’s, but didn’t get the chance to further check yet