thumbstall

Drag was provided by the angler's thumb, with or without a leather thumbstall.

The Hindus used instead a thumbstall of leather.

A bagged charge slid down the muzzle while the captain stopped the vent with a leather thumbstall.

Hickson was sewing up the frayed edge of his leather thumbstall which protected his hand when a cannon was swabbed out.

The gunner had to stop the touchhole so that the rammer could not drive a jet of fresh air down the barrel and so ignite any scraps of remaining powder, and Hickson's old and blackened thumbstall betrayed how long he had been an artilleryman.