Some of the later Jones type actions were snap actions. That is to say, the action snaps to the locked position as the barrels are closed. The lever and bolts are spring loaded like a toplever rifle.

My Purdey is such an animal.

Mac, another interesting feature is the third grip on the Jones action. My Purdey also has this feature. There is a sliding Purdey type bolt that engages a bite in the rear of the rear lump. I assume this H&H has the same arrangement.

You can see the third bolt in the above photo.

Curl