AR2201

"I'm trying to figure out what this backthrust could be that is DR
specific (the pivot action?) and referred to as both distinct from
pressure and seems to be able to be calculated."

Why is it DR Specific ?

Shotguns are made on the same actions so
why doesn't it or wouldn't it apply to them as well ?

While you are at it, do you think different actions
and thrid bites have an affec on this calculable force ?

ie Does a Webley Screw Grip action which used a Spade shaped
3rd bite have a different backthrust to a Webley PHV1 Action
which used a Club Shaped 3rd bite. Or is a Greener Cross
Bolt better ?

What about Self Opening actions. Does the Self Opening feature
affect the amount backthrust ? An example would be the Lancaster
"Wrist Breaker" action.

500 Nitro