I have a Remington Lee Model 1899 Sporting rifle in .30-30 with a rough bore, and was thinking of having it rebored to .35 Winchester, one of the original chamberings for this rifle. Love to hear thoughts on this cartridge from actual users.

The 35 Win (NOT self-loading) is slightly less powerful than the 358 Win. As such, there would be little difference in effectiveness on game. A good friend of mine, bullet maker Jack deRosier and virtually his entire family uses the .35" bullet for all of their big game hunting and with very good results. for deer or elk they use the 358 Win if distances are short and the 358 Norma for open country. Provided you don't shoot beyond the cartridges range limitations, I'd expect you'd be very satisfied with the results of the .35 Win.