Sorry, did not notice this post, been some long hours in the shop.
Go with the Accubond. The A-Max is a great bullet but its not a good match for the 7mm AM. It would expand like a varmint bullet even out to the 500-600 yard range. Believe me I have tested this!!! For lighter big game its acceptable if yoru not worried about extreme tissue damage.
The 160 gr Accubond can be loaded to the full potential of the 7mm Allen Magnum where it shoots accurately and shoots suprisingly flat out to the range your looking to use it at.
Terminal performance is second to none, will survive close range impacts yet expand well at ranges out to a bit over 900 yards.
This year I used Ol Green, my old lightweight 7mm AM to take a good pronghorn at 823 yards and bullet performance was excellent even on that lighter game, full expansion was obvious with the tissue damage caused.
I also took a good mature 5x5 whitetail just last week at relatively close range, around 250 yards at a full running whitetail. At this relatively close range the bullet entered near the back of the chest cavity, drilled a whole through the heart and broke the offside shoulder with the bullet found just under the hide on the offside.
Considering this bullet was launched at 3450 fps (mild for the AM) it showed plenty of penetration performance even at closer ranges.
Its really a very good ALL AROUND bullet choice for the 7mm AM. In my Rem based 7mm AM, I load it to a good but moderate 3450 fps. In my Raptor Stalker or LRSS rifles, you can realize the full potential of the 7mm AM and load it up to the 3550 fps range in most rifles. Most other custom receivers designed for the Lapua will also support this class of velocity depending on specific barrel lengths and specific barrel speeds.
Retumbo has proven the best powder for the 160 gr Accubonds in my testing. Another good one may be Ramshots Magnum powder but I have not tested it enough yet to fully endorse it.