I've had my best luck with rebedding 99 forends by checking to see if the rear end of the forend is binding on the front of the action. In a surprising number of rifles there's considerable pressure there, and if it's on one side in particular it can cause horizontal stringing. I just relieve any pressure with a fine file rather than epoxy-bed. This essentially free-floats the barrel AND forend.
I've owned a bunch of 99's and generally expect scoped pre-million serial numbers to group 3 shots in around an inch at 100, and some have done much better.
I'd also roll your ammo over a piece of glass. If you can see the tip of the bullet "wobble" then the bullet is seated pretty crooked, enough to cause definite fliers.
