Well, it turns out that 338LM isn't that much harder on the target plates themselves (AR500 armor plate), but it is more likely to damage the mounting systems and/or jostle/move some of the A-frame target stands that we used. There is a trade-off between target stand sturdiness/durability vs. how easy it is to transport the target stands and cost. Since virtually all the targets had to be moved in preparation for the match, super-sturdy stands and placements couldn't be used. I do prefer to allow 338LM when possible, but going into this match, we didn't know exactly what type of steel targets we had and how good the stands were.
Knowing the shooters at this match, I think there would have been either zero or only one 338LM shooters had we allowed it. The guy I have in mind has a 308 and a 338LM, and the 338LM would have been an advantage. However, the majority of these guys are shooting moderate 6.5mm cartridges-- if they wanted maximum ballistic advantage, they'd be shooting a hotter round.
I do know, roughly, what the 260 recipes were from data gathered in the survey. The majority of the 260 shooters used R-P brass, with formed Win or Lapua brass following. The two powders used by the 260 shooters (and I include 260 Ackley in there too) were H4350 and H4831SC. Primers were mixed. The most popular bullet was the 142 SMK followed by the 139gr Scenar and the 144gr.
