There is no way to tell what size groups you will get. To many variables, gun, sights, shooter, loads ect. Sounds like you have a good bit of experiance with handgun though and I would guess you`ll have pleanty of accuracy to take deer at 100 yrds., with a good rest, and maybe farther. I`ve only taken 1 deer so far this year and it was with a .357 max. on an Encore frame. Over the years I`ve killed more deer with the .44 mag. than anyother round, and like you I`m always looking for another gun. Next year I`ll be hunting with 2 handguns. A .500 S&W, scoped, for stands and a Ruger SRH in .454 for walking and driveing.