Ive got one on my 270 WSM featherweight SS and it does as advertised-groups tightened up about 1/2" at 100 yds. I'd put one on my 99F, but don't want to fudge with the factory sight.
If you use it make sure you have enough oil between it and the barrel. I didn't and mine is so tight where it is it won't go any further up the barrel and I'm afraid to use any more force less I damage the rifle. Any more rifles I get with no front sight will get one too.
