Ah Ha!
Seeing those 3 protrusions from the long rear of the action I thought that it had coil springs powered being so much in line.
The safety mechanism got me though - certainly blocks ANY potential primer from being hit!
Simple but very effective!
Thanks kuduae - love your explanations of these marvellous old creations, still going now over 100 years young with tender loving care.
Always appreciate your timing mate, when we're all stumped, your spot on as always to help!