Thank you, rfd, for useful information and feeding my curiosity.
Where do you obtain the hex sockets? I take it they must be a little different from one I might use with a breaker bar, since they need a surface for the wrench to get a purchase.
I thought a picture in one of your past posts showed the rcorp wrench on the hook of a breech plug. If that was the wrong impression, I'm glad you provided more information before I messed up a rifle.
I kind of dread taking massive force to my two Investarms/Cabelas Hawkens' because their 15/16", .58 caliber barrels are kind of scarce and I'd hate to bugger them up. But I would like to have the plug threads clean and properly preserved and feed my curiosity by a closer inspection of the plugs.