[quote=L. Brown]Pooch, I'm thinking more overbored than underbored. I measured the new Ruger Red Label at .739. Discovered that a new Guerini Tempio (20ga) was .625, so also overbored by .010. [/quote

Most continental 20 bores are bored to 15.9mm or.626"as standard not the ,615" that the was used in the UK so it is not "over bored" as a feature just normal size for modern Italian guns.