As far as my action goes, it appears that the radius on the front underlug is ever so slightly worn away. If I look close I can see daylight. In Ellis Brown's 2nd edition which I have, I think the shotgun he re-hooked was very loose. I am just concerned about mine. I'm sure it would be ok but I'm not putting all the money into this project and not doing it right! IMHO if you fit a larger pin into the action, it will theoretically move the barrels back towards the standing breech. I'm assuming you would then need to fit the underlug to the new pin diameter. Brown also states that you don't want to install too large of a pin as it will weaken the action. I am starting to agree with most members regarding the Greener crossbolt. My Sauer has one, but it seems to me if you do have catastrophic failure, what the hell is that little thing gonna do? They do look cool though. I can imagine that if the lugs gave out during firing of the weapon, the barrels would flip forward violently and relieve any pressure right in your face. I don't think that little pin can hold several tons of energy. But then again, I'm far from an engineer.