Haven't used them myself, but those I have talked to that use the Barnes TTSX reckon they are the business. They now do a line called LRX (basically a slippery TTSX) and have a 127gr 6.5mm, BC 0.468. Might be worth a try.
Half tempted to try the 7mm and 338 variants (168gr and 280gr).
Must say though, I'm surprised about the amax blowup at 500m. Might have expected something like that at really close range, although I have never experienced that either...
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