Check this little 25 caliber out.
The three in the middle are 257 Allen Magnums loaded with the 130 gr Wildcat Bullet to +3600 fps. The two little guys on each side are 25-06 rounds loaded with the 115 gr ballistic Silvertip.
This is the APS Extreme Sporter. This rifle is chambered for the 257 AM and weights in at 9.75 lbs with this stock.
I am building a light weight version of this same rifle with a heavy fluted 30" Lilja #6 contour barrel and a McMillan stock. This rifle should weigh in between 8 1/4 and 8 1/2 lbs.
Groups with these rifles average in the .3" range at 100 yards and in the 1.5" range at 500 yards with taylored loads.
This may be more rifle then your looking for but for the ultimate in flat shooting and accuracy in a relatively light rifle they are nearly impossible to beat.
As far as a perfect yote load, if you don't care about pelt damage, the 100 gr Wildcat bullet will average 4100 fps in this rifle.
So far I have only tested out to 350 yards but with a 100 yard impact of +2.3" the 4100 fps, 100 gr pills land +3" high at 350 yards. I suspect at 500 they may well be only a couple inches low!!!
With a Holland QD brake fitted you will see the bullet land at any range with a solid shooting position. Almost more fun then should be legal.
Imagine a 257 Wby, only with another 400 fps added to its top loads and true long range varmint accuracy.
There is also a 6.5mm and 270 version.
Again, probably a bit heavier and larger case then your looking for but for 500 yard shooting, there really is no hold adjustment needed, especially on deer size game.