Don't waste much time on 69 MK's at 500 yards. If the wind is blowing, this bullet is all over the place.
If you're are going to shoot the 69's anyway, try 25.0 grains of Re-15. This load will yield about 2850 fps at the muzzle, maybe a little more.
You really need to try 75 grain Hornady's, either the boat tail or the ballistic tip bullet first, then 73 grain Berger's, then 70 grain Berger's (which ain't going to be much better than the 60 gr MK's).
Re-15 will give you good case fill with all of these bullets, and all the speed you are going to get from them without scary loads.
And you don't need to crimp anything (bullets or primers).
By the way, Sierra sells seconds by the pound at their factory store - this is an excellent way to get bullets. You will need to sort out the culls, wrong caliber, and wrong weight bullets, but the number of bad bullets mixed in is small. They won't ship these bullets.