At what point does the 1:8 become too fast? I mean what weight bullet? 55, 50, 45 grain?

There are a few shooters that have reported jacket seperation with sub 55 grain bullets. If I remember correctly is was actually sub 45 grain, but I'm not sure. I don't pay much attention to this because I never use anything lighter than 55 grain ammo, and I don't hunt.

FWIW, Kuleck & Duff ("The AR-15 Complete Owner's Guide") list 62 to 80 gr as the optimum bullet weight range for a 1x8.

I have found their table to be valid for my 1x9 (50 to 69) ... 62 gr FMJ seems to be the most accurate bullet in mine.

I do not believe there is an "optimum" bullet weight.  I have a 1:8 wilson, and I shoot from 45gr to 77gr.

45, 52, 68, 69, 75, and 77 are all sub-MOA in a good load.

Some of the best groups ever out of this barrel are split, between the 45 and the 77's, with the 77's being a bit more consistent.

You are either stabilized, or you arent.... and overstabilization is a myth.... as long as your jacket isnt seperating.  At least, that has been my experience from owning, shooting, and handloading for mine.

I was looking at getting some 45 grain Winchester hollow point varmint loads.

Quoted: I was looking at getting some 45 grain Winchester hollow point varmint loads.

This is what I shoot in mine - sub MOA, and very consistent.  (NOT "3600 fps" tho, as the box says)