lol, any title with 'ultimate deer rifle' is gonna see some action, well played
assuming some 21st century options are allowed??? wink wink nudge nudge
all of you got it wrong, I built the ultimate deer rifle, hear me out
adjusts from about 34" to 36" to fit anyone or any amount of clothing or positions you may shoot from, pretty hard to build the ultimate deer rifle if you don't have that adjustability imo, it's short and handy anytime, good for all situations, bush, blinds, or open country off a bipod or over a pack etc.
next, short and long range capable as deer live in the bush and in the open country, the three...optic, rifle, and cartridge, need to be capable, we need 3-9x on scope, moa or less on the rifle, and a cartridge spitting bullets above .2 SD and landing with about 1700 fps to 500 yards on the far end, most people can't shoot well enough at that distance to stay in the pie plate anyway and extra horsepower is inefficient on recoil and staying in scope
scope, 3-9x40 Trijicon accupoint green dot duplex with a Kenton industries speed dial turret matching the load, lets you do bush, low light, to dial em up to 500, weighs only 13.4 oz, no fat and rides nice in 1" low rings, still clears the barrel, maintains cheek height without any risers required, oh and no batteries, can't express how wonderful that illuminated green dot is for intuitive placement for the kids or myself (myself with aging eyes), my kid can explain how nice it was on a black bear at 10 yards also

(lot of black in the scope on that one)
rifle, something known for moa or less accuracy, in my case chose the Ruger American Ranch, 16.1" barrel, maintains 3/4 moa in field conditions with factory ammo to 500 yards, reliable easy to clean bolt action, and just fancy enough to beat the shat out of
cartridge and ammo, 6.5 Grendel with 123gr Hornady Black ELD-M ammo .252 SD and .5 BC, more than enough SD for class 2 game (deer & sheep) and actually gets into class 3 class game SD recommendations of .25 and higher, it launches at 2386 fps but nice BC keeps it humming along and fighting wind and still holds 1700 fps to 500 yards from my short barrel 'deer rifle', I just dumped a fat whitetail doe at 420 yards DRT with it and 1800 fps impact and my kids took a mature buck at 300 and another doe at 355, it was a dial up season across the valley this year, dry, warm and windy, the blind on the bush edge wasn't producing so had to focus on the treed quiet shaded out of the wind side of a valley from a distance which meant dial up sniper action
weight not super important as more of it only eats recoil and keeps more happening inside the scope or help for follow ups or make easier for the whole family to shoot well, my rig currently maxes out all these checkboxes being at 8 1/4 lb bare scoped rifle and only 6.5 ft/lbs recoil energy, so watching the impacts a thing, keeping them in the scope a thing, and follow ups, as well as anyone shooting it well are also things, shoot ability goes up with weight, carry goes down, we're at the upper end of this typical range, I choose shootability now over ultralight sheep rigs as I'd rather pack the extra couple lbs and have even more to pack out at the end of the hunt
bonus on the cartridge is the game doesn't seem to hear it, so keeping things in the scope and follow ups all the more possible, we even had a coyote give a second chance this year, weird
so ya, I believe we have put together the ultimate deer rifle, not sure it could be topped or I would have built it
we've put it to the test over 4 seasons now and 3 shooters, 1 dad, 2 kids, 1 experienced, 2 rookies, and the freezer is full, batting 1000 with 10 head of big game, 5 from the old man, 5 from the kiddos (ages 12-14), from 10 yards (black bear) to 420 yards (deer) and one moose thrown in there for good measure, also one bighorn sheep, but 7 of the 10 are deer, 5 of those bucks
oh, the critical thing we did to make the system work was put that rifle in a chassis and use AR butt stock on a multi-position buffer tube, so it's quick fit to anyone, regular stocks won't do anymore, even for me, being able to quickly adjust to prone, or lots of clothes or whatever is too handy to give up, never mind fit any shooter quickly