I suppose the thread title says it all. In looking at a gun (on line) with said action, all I see is an English gun with a straight grip boxlock, top lever, side clips, and third fastener (not real clear how), all fairly ordinary looking. I suspect it has something to do with the 3rd fastener but perhaps there is more to it.

Hallowell's doesn't list it in their dictionary. Perhaps someone here can clearly articulate what makes a gun a screw grip?

Just looking to improve my vocabulary.

Thanks

The extension rib is the "third fastener", and the part that constitutes the screw grip. As the top lever rotates toward the closed position, a large screw rotates with the top lever and pushes down on the rib extension as it rotates to insure a tight lockup. Of course the two underlugs are the basis of the locking mechanism, but the Webley screw grip adds a bit of class to an otherwise simple action. Several makers used the Webley patent on some of their guns. I won't try to list them all. Some were top of the line full sidelocks, stocked to the fences, like my Evans pair. Some were simple, unadorned boxlocks, like my old W&C Scott 16 gauge.

http://www.wrleeson.co.uk/design2.htm

Thanks to both of you. I think I understand now.

Thanks for the great references, Bushveld.

I have an Evans boxlock, #2 of a pair, which was made by Webley & Scott based on a Webley patent. The book on WC Scott has a photo of the receiver. It's the most expensive boxlock they produced after the merger with Webley. It's a screw grip.

The simple way to tell if a gun is a screw grip is to look in the slot in the breech face into which the rib extension fits. You can see the threads.