If your scope is accurate, if your 600 actually matches your rifle, and if your target is bigger than 20 inches and your rifle is a laser... then sure.
A 300 win mag would need 63 clicks to get from 600 to 1000*... 63 clicks is a pretty decent amount of travel. If the specs are right you only have 80 (160 total).You're going to need 16 MOA of travel, the scope has 40 MAX (20 up and 20 down) so you'd be squeezing by there and hoping the adjustments were still true that far out... unless you used a 20 MOA scope rail to add some elevation...
Also, isn't that a sfp scope? So you'd need to know which magnification the bdc is accurate at and either keep it there or know how to adjust with it.
But yeah, if the scope is repeatable and accurate all the way out, if it really has 40MOA of adjustment, and if your ballistics arn't much worse or better than what I put in.... Then a person capable of hitting 1000 yard targets should be able to do it with that set up. **
*ok, this is a very specific formula for a specific rifle at a specific elevation, bullet weight, muzzle velocity etc....so it's not exact for every rifle/bullet/300WM and it was done on a ballistic calculator so even still it is only going to be *close* not exact
**I had to swap some numbers around mid post, so my math may be off.