The other day I ran across an older 870 magnum. It has a 28" full choke barrel that a previous owner has had threaded to accept screw in chokes.
I tried a rem choke but it won't even come close to working. I was wondering if there is a way to figure out what threads were cut?
It being an older factory barrel I'm sure it's probably a little thinner at the end and g the barrel, so that makes me wonder about thin wall chokes
Likely Tru-Choke...
99% of them will be tru choke threads. Looks like a Win/Inv choke