Not all 30" O/U's are created equal either....its the little things...
a. like the style of the forend...Schnabel, beavertail, etc...
b. some guns in the grip or throat area...are narrow ( Beretta ) / or thicker ( Browning ) ...and some have palm swells like Browning has had for the last 10 years or so on many models.
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I can adapt to a different forend style ( if I had to )...but I have a hard time getting comfortable with a gun that has a narrow throat or grip area..vs a throat or grip area that fills my hand...
I also like ported barrels ...( and some folks don't )...
I like a moderate height rib... and a parallel comb ( so comb is parallel to rib )...
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My general purpose O/U's are all Browning XS Skeet models in 30" ( one in 12ga, one in 20ga, a 28ga and a .410 )....but that model is no longer in the catalog ....so if I needed a new gun, I'd probably be forced to look at one of the 725 series...which I'm not crazy about.
Brownings Cynergy line of guns....tends, to me, to feel more like a Beretta...than the traditional "blockier" feeling of the Browning Citori XS Skeet, XT Trap models that I like.....
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Browning Citori 725 Skeet, with adjustable comb ...is the closest gun they have today to the XS Skeet model they made for the last 15 yrs or so...that I prefer. 725 Skeet with adj comb lists now for about $ 3,500 ...but there is one in a shop in my area for about $3,300 I think...