Feel like a pocket gun after those 8.4" rimfire revolver-rifles! Help empty out your pockets... .22 WMR ammo aint cheap, either! It runs $9-$15 a box of fifty at Wally World.
Of course, don't look to me for help... last fall I 'found' an ANIB 4" 651 I could afford. I still, three months later, have to take a lemon to chew on when I take it to the range. I need something to get the possum-eatting-poop-out-of-a-hairbrush - aka Cheshire cat - grin off my face, lest range folk think I am simple. Probably too late for that.
Seriously... I have no idea why I had to have my J-frame .22 WMR - but I sure am glad I got it!!
m657- Have you held the 6" 648. I find the full lug 6" barrel .22s a little front heavy (have a 4" 17-6 full lug that balances great). Having said that, the more barrel you have for .22wmr the better the round performs. You could get a blued 48 in the 8 3/8" length to match your other two. Try to handle one before you buy.