Your'e definitely pushing the threshold and working well beyond my comfort limits, but to each their own. I mean, I grew up thinking a 30-30 was all the deer rifle anyone needed so what do I know.
I am very impressed with my Howa Mini. Yesterday, it put five 120-grain ELD-M's into 3/4" at 100 yards, and four of the five were touching. That's as good as I can hold a 9x scope so I figure the round and rifle is at least as accurate as I am, if not moreso, which is all I need.
So far on game, it has performed well but I need some more test data to really be convinced. The last deer I shot acted pretty weird, walking (not running) about 40-50 yards in my direction before falling over, despite the 1" exit hole in his side and a perfect double-lung shot. Took him a while to die too (he died less than 80 yards from my blind, and I could see him breathing in my 10X binoculars). That might have been the bullet though. Folks are saying the 130 Sierra Gamechanger might be too hard for the Grendel, so I'll give that 120 ELD-M a try and see how they do.
I am slow to have faith in a rifle, but once I do I usually keep it for a long time. My Tikka 7mm-08 has earned my trust (produced a 3/4" group at 200 yards yesterday with my son shooting it) and this Howa Mini is well on it's way. Seems like a perfect deer caliber inside 400 yards to me. It has replaced my interest in the .243, which is saying something considering how highly I regard that caliber for deer hunting.