Wow! A great photo, and a truly wonderful shot. I would like to comment however on the cartridge, in the spirit of ebate and discussion:
the .284 didn't make too much of a splash back when it first came out (196XX??), probably because of the existing and ballistically hotter 7 Rem Mag, and also the Winchester 88 and 100s it was initially chambered in.
Nice combos, but not exactly the best for long-range shooting. Horrible triggers, for instance! I remember buying my dad a new Win 88 and I chose the (bohh-rinngggg......) .308. Still, a v. nice deer rifle, and it still shoots into <1" @ 100 yds so...
Meantime, the benchy-boyz decided to neck that .284 up and down, creating the .338-284, the .35-284, even a .375-284!, and then the .223, 243, 257, & 264-(6.5)-284 versions. Of all of them, the 6.5-284 proved the most impressive down-range ballistics and accuracy.
It now holds many many world-class 1000 m target records. And whyzhatt? Well, of course you can always make up a bullet in literally any calibre (sorry: I used to be a Canuck...) to meet some Ballistic Coefficient goal, but the readily available off-the-shelf bulletry comes best equipped in 6.5 and .338 calibres. Not that you couldn't make up a, say, 135 gr .243 bullet, but they are a bit hard to find, right?
As well, the reason the boyz out there case their 6BRs and 6.5-284s when out on those windswept plains is that the sidewind issue is reduced by going to a mucho-heavier slug. Hence, the .338 Lapua (or my .340 Weatherby for that matter) tied onto a railroad-tie gunstock and firing a 300 gr Berger for those 1500 yd matches. But then your shoulder gets to be the loving recipient, and 150 - 200 rounds through your prized Lapua can get a bit tiresomw indeed!
So, your 6-284 must be impressively soft to shoot, which improves your accuracy potential (no flinching), but in the ever-present gusty and highly variable cross winds in antelope valley, I'd bet the 6.5, in a 140 or 150 gr bullet would deliver better performance @ longer ranges (less windage correction) and of course, about 15% or so more energy. Not that you seem to have needed it, huh?
I hope to personally get out there next year with my own long-ragne wonder, a 6.5-06 Ackley, which launches the .264 cal.140 gr pill at about 3230 fps, conservatively. The rifle is one of my own, a modded REM 700 (accurized receiver, Sako extractor, Timney Trigger, 26" stainless [& very smooth!] Douglas medium wt bbl with a QUE adjustable muzzle brake;, NP3 finish, and a Leupold Mk4 with TMR reticle and thumbhole B&C stock: sub -.7" MoA 5 shot groups).
The much bigger question is: is antelope even edible? I hear either 1) it's totally inedible, stinky and tough, or 2) it's wonderful.
Oh-oh: basic disagreement there!
Again, great shooting and photo!