My barrels have numbers stamped underneath at the breech end. Don't know if Tex's barrels are marked underneath too, but might help with picking a different card, if size is the problem.
the bores (muzzle end) on my Ped. 12 ga. measured .725" and .711". Factory info calls them cylinder (no choke), and improved. Noticed the numbers stamped on bottom of barrels at breech end, 4, and 0. The 0 (zero) I figured right away as zero choke, it's on the 'cylinder bore' side. The 4 took me a minute, but I'm assuming it means .4mm constriction. Pedersoli IS Italian, and therefore metric. .4mm is about .0157", or .725"-.0157"=.7093". close enuff fer me. Can definitely feel the choke when I run tight patches down the 'improved' bore too. The .725" over-shot cards I have won't be big enuff.
Smokin', if I wait till I get my limit to drink a Silver Bullet, that case will last me all season, and then some!! The adult beverages never come out till the guns and game are cleaned and put away. And good to know HF might have a punch. Neat.