I'd take the heavier bullet but there is a best of both worlds, the 168eldm superformance. I don't remember what velocity they run at, but it's fast!
I use the 168 eld in my 308 and imo it's one of the best deer hunting bullets available
Not sure what else you're wanting, I think the amax/eldm are top notch deer killing bullets.
This is an excerpt from Nathan foster's terminal ballisitcis website. I'll provide the link below>
Hornady's A-Max bullets are simply outstanding when used for hunting. The 155 grain Amax is best suited to smaller deer/ light bodied game, effective out to and beyond 800 yards. The 168 grain A-Max produces excellent results on a wide range of body weights, though best suited to game weighing no more than 80kg. Wounding performance is interesting in that following a cross body chest shot (down to 1400fps impact velocity), fragments of the A-Max can be found in other vital organs including the liver and kidneys and the arterial system of the spine. Perforated bowels can also be expected from time to time. The Amax is very forgiving with shot placement though - it should never be expected to produce fast killing with poor shots as it is not 100% reliable in its ability to produce fragmentary wounding throughout. Carcass inspection is very important prior to meat retrieval.
The 168 grain A-Max is a reliable, wide wounding, fast killing bullet, down to velocities of 1400fps. From an MV of 2670fps at minimum, this equates to 800 yards. Nevertheless, generally speaking, it is difficult to ensure fast clean killing on game past 650 yards due to the effects of wind drift on the .308 Winchester cartridge. Using the .308 and A-Max past 650 yards requires great skill<
>The 168 grain A-Max bullet with its higher SD, has a light advantage over the 155 grain bullet with fragmentation occurring over a longer distance during the course of penetration. Ballistics gelatin is completely hopeless as a means of understanding the terminal performance of these loads. While the 155 grain bullet will occasionally suffer surface bullet blow up when used on tough animals, the 168 grain A-Max handles a wide range of body weights and densities, producing better performance on larger animals at longer ranges where velocity is down towards 2000fps. Hornady have done very well with the SF version of the 168 grain A-Max load and it is impossible to duplicate these velocities in most 20-22" barreled rifles.<
I pulled it from this page:
https://www.ballisticstudies.com/Knowledgebase/.308+Winchester+7.62+NATO.html