If you want a fun, accurate and easy to reload and shoot 600 yard gun, then look at the 6mm BR in the straight, Dasher or BRX version. This and the 22 BR (1-8 twist with 80-90 JLKs) are the guns to beat in the 500 yard egg shoots, 500 yard groundhog events and such. Several .5 inch (yes that is on half inch) 500 yard groups have been shot with them in these shoots. Also the BR with 1-8 twist is more than excellant at 1000 with 105-107s except in higher winds. The Dasher and BRX are improved versions that are really making marks in the F class 600-1000 yard competitions. 105-107s are running 2950-3000 fps with 28-30" barrels.
I am building a 6 BR improved now for egg shoots and formal comp in 600 and 1000 yard matches. IBS is probably going to open 600 yard matches for BR this fall.
Build it with custom match grade barrel and at least min neck for Lapua brass (think .271), mine is .267. Short action sendaro with custom barrel.
Thanks for the feedback. If all that's needed is a 6mm BR and a 1-8 then I need to think it out on what I have now.
My 40X in 6mm Rem International was made for up to 300 meter position competition and has both a free rifle stock and the orginal 40 X target stock. It's new 1-10 barrel shoots 100 gr bullets a 3100 fps. I need to try this one out at 600 yds before I jump ship.
I have an adversion to wildcats and improved cartridges now that I have been around the block more than a few times. The 6mm BR as is seems like a path of least resistance however most here are going with the 6mm 250.