Grouping Best Recipe at Long Distance

[Triple BB]

Would appreciate some thoughts on grouping loads at longer distances. I have a 300 RUM that I'm shooting 212 grn ELDX's out of. I've loaded a wide variety of bullets and powders to get where I'm at. I have two different recipes using the same bullets. Both are grouping at just under a 1/2" at a 100 yards. This will be my test to see which one provides the best MOA at longer distances. Wondering where I should start. I was thinking either 400 or 500 yards. After I get it dialed in, I'm hoping it'll be an 800 - 1000 yard gun...

Thanks

 

[dok7mm]

Either range will work, but if your load doesn't hold up, I would suggest a ladder test to establish exactly what will work at longer ranges. It will really help if you chronograph your velocities to compare to the ladder results.