The original AZShooter here, since 2005 .... I like using the 230 gr match target in my 300 RUM. It always exits and is quite devastating to the elk it has hit. Largest was a 6 x 6 that staggered a few feet and was DRT.
I shot one of my 300 RUMs this week a few times in CO. Load is 200 AB with 91 gr 8133 at 3150. Yesterday the wind was gentle from the left; held 1 MOA left and hit my 2" aiming circle at 715 yards. The day before I shot it in a stronger wind with a 2.5 MOA hold and just missed the 2" circle. Yesterday the winds started to blow at 15-20. I was shooting an Edge at 910 and zapped my target with the 300 RUM profile in my SIG2400ABS and immediately noticed my elevation was wrong (not enough elevation) but also noticed my wind drift was 5.8 MOA. I switched to the Edge profile which showed more elevation but significantly less drift. I ended up holding 4 MOA; actual drift was 4.5 MOA. Edge load is a 300 Berger at 2865. So while the RUM with a 200 AB is flatter shooting, it does drift more. I also shoot a 220/225 ELD in my other RUM but left that in AZ. But the 200 AB load is what I am using for elk this fall.