Sam, here are some 6mm load comments from Richard Franklin and Gun of the Week 42. If you call Richard, he'd probably share his starting 87gr load:
Load Development and Accuracy
Working up a load for this rifle was simple. Richard tells us: "I've been shooting the 6mm Rem AI for over 15 years. Whenever I build a new one I start with the 75gr Hornady V-Max, seated pretty far into the lands, pushed by 51 grains of Vihtavuori N160, working up to about 52 grains. N160 seems to be perfect for the case, yielding great velocity,about 3860 fps) and excellent accuracy. This gun is a 14-twist, and I normally shoot the 75gr V-Max. As far as I'm concerned, the 75gr V-Max is the best factory bullet you can shoot. It's the most consistent, with a better BC than other brands in the same weight range. But to get a 75 to stabilize in a 14-twist, you have to really boot 'em out there fast--you need to smoke 'em out at 3750 fps or better. The faster you push a 75 the better it's going to shoot.
I've also tried the 65gr V-Max. It gives great velocity, but it doesn't have the BC of the 75-grainer. With the 65, I recommend 47.5 grains of Varget or 47.5 grains of IMR 4064. Both of those loads will push a 65gr V-Max about 4,100 fps. Some 6mm Rem AI shooters prefer to shoot the 87gr V-Max from a 10-twist barrel. The 6mm Rem AI set up with a 10-twist barrel to shoot the 87gr V-Max is about the ultimate long-range varmint caliber one could ever want. With a BC of about .400, the 87gr V-Max is a great performer out past 600 yards where it will surpass the 65gr and 75gr V-Max. It cannot be launched as fast as a 75-grainer. The 87 starts out a little slower but at 1000 yards it is going faster, hits harder and is flatter shooting than the lighter V-Maxes.,Note: the loads mentioned here are all fairly stout; they may be too hot for your rifle and your conditions. ALWAYS START 10% LOW and work up.)
But overall, I prefer the 75-grain V-Max over its heavier and lighter breathren. The 75 offers the best balance between velocity and BC. We varmint hunters like very high velocity for a flat trajectory and explosiveness,the "red mist" effect) on the target. With the 75 you can use a slower twist, and that means less drag in the barrel. So the slower the twist, the faster you can shoot. Keep in mind, however, that not all 14-twist barrels will stabilize the 75s. I've found that some 14s just won't shoot them fast enough to stabilize. I can't really tell you why--it could be that the twist rate is slightly slower than claimed, or it could be the bore diameter is a little tight. Every barrel is different. If you want to be safe, go with a 13-twist. My 14-twist works great with the 75s though, and I feel I get more speed with a 14 versus a 13-twist.
One last thing about bullets. I've tried the Noslers and I'll stick with the Hornadys--they're much more consistent, and they're more accurate for me. Some folks have tested Noslers and V-Maxs with a Juneke machine and they found a higher defect rate with the Noslers. You'll have more bad Ballistic Tips in one box than in several boxes of V-Maxs. You can't beat the V-Max for accuracy. As far as primers go, I use Federal match primers, with the exception of using CCIs in hot loads in small cases such as the BR and PPC families of cartridges. The CCIs will not pierce as easily as the Federals."
