Lengthening of forcing cones along with overbore will give very uniform patterns. My Kolar SC has no discernible chamber and the patterns are the most uniform I have ever seen.
Conversely, felt recoil is subjective and there is no scientific evidence that supports the claims.
Removing metal from an engineering perspective on an item designed for specific pressures is not something that i would do or recommend. Many believe that the attributes of lengthening a chamber or forcing cone are worth the effort but I don't believe anyone can supply scientific evidence that it accomplishes any quantifiable change to be worth while and the safety considerations far out weigh any possible gains.
In short, I leave my field guns alone and purchase Target guns with overbore barrels and long forcing cones.-Dick
