I’ve seen many old barrels where the tang broke right there. If you have 1/8” at each side of the countersink you might get away with a cold bend. I hold the end of the tang in a vise with the barrel pointed skyward. Then move the muzzle till it bends some. Check, replace in the vise with maybe more clamped in. Rinse and repeat.
If there’s not much metal beside the countersink, heat to orange and lay it on an anvil bottom flat facing up. Tappety tap.