I have shot a couple loads with the 210g uld and my 300 RUM. Results have been satisfactory. I am using Retumbo and Fed 215 primers. Have been trying anywhere from 88.5g-92g. Have found my dads rifle likes the lesser charges. Shoots 89g at 3000fps. Groups right at 2" at 200 yards. Not the best group in the world, but its better then the rest. Also trying berger 210g vld's, same powder and weights. 89g is also shooting the best with the bergers, again right at 3000fps. I will shoot the ULD's at 500 yards and try to come up with a rough estimate of a BC based on drops. The bergers have a BC of .640, and are pretty spot on at least from my standpoint. The ULD is the same length, the ogive is a tad different, but ill start at .625 and see where that puts me.