I say this in general, o/u are typically heavier in weight. Alot also depends upon the wood, and barrel length, etc. If you take a look at weight ranges, a sxs in 12ga will range anywhere from 6lbs to 7lbs. The o/u will run from 6.5lbs to 7.5lbs. Regarding titanium, the Franchi Titanium o/u weighs 5.9lbs to 6lbs. These are the only modelsin production but I expect to see moretitanium shotguns in the future.