I have two 24" 12g Remingtons, i think they are called special fields. One has an english stock which i prefer
I would never hunt grouse with a longer barrel, which would get caught up more often in the thick stuff
Having to swing faster is not an issue, it is a necessity. A member of my duck club was known, and chuckled about behind his back, for being an incredibly poor shot. He would go thru a box of shells and only get 1-2 ducks, or none. Then one year he limited on both days of the opener, went 4/5. We were blown away, asked him what he was doing differently. He held up his 24" barrel. So, when i get in a slump duck hunting, i take out my 24" grouse gun and it gets me back on track
Besides, there is a wide pattern using 7 1/2s