I don't know about downloading the .222 to match Hornet ballistics and decibels.
They are totally different animals !
To my mind, the Hornet was meant to shoot lighter bullets, and quieter, and does it well, although there is a bit of overlap between them.
Fortunately, I have both calibers, and they both shoot good with the 40gr Nosler BT and the Savage M40 Hornet the 50gr Hornady SPSX, (14" twist),
although I generally stop at 45grs with the Hornet, (as the Anschutz 1730D has a 15.7" twist) and just 50 and 52grs with the 14.2" twist Anschutz 1742D .222 .
I shoot both calibers at around 3,000fps,
(the Hornady factory 35gr V-Max Hornet round does 3,000+),
so the Hornet is just about up there with the .222 using the modern powder and projectiles available.
I generally get tighter groups with the Hornets at 100, and the low pressure Lil'Gun loads prolong case life.
I once loaded down the Hornet with lead cast 40gr, and around 5 grs of flake powder, just for fun,
and it shot horrible !!!
So won't go there again.
I'm no benchrester, and neither are the rifles.
They are all unmodified, out the box.
I shoot with RP, Win, S&B, Hornady and Highland brass, so nothing special there either.
I would guess that the best brass would be Norma, Sako, RWS or Lapua (if available !)
Good case preparation, loads, and projectiles is part of the answer, as is perseverance,
but I guess, as with everything, there are some rifles out there that just won't shoot.
I just neck size the Hornet when I can and use a Lee crimp die to get consistent neck tension on the projectile.
It all seems to work well as I am happy with groups from .25" up and within MOA unless I cock them up.
Killing power ?
I don't know if I'd want to shoot Coyote size animals with a Hornet though.
.222 would be better,.... but my choice would be a .243 ! (and lots of noise !!!)
cheers,
SS