He probably doesn't know exactly what tunes work best yet??? Until a few months ago I didn't realize that 900-ish fps is a sweet spot as far as wind drift is concerned, that thanks to BallisticBoy.
Barrel harmonics come into play so finding the compromise between ES, the barrel harmonics, and a more efficient tune, might make that Panthera shoot twice as good??? And I think there are superior slug choices as well.
SK SP ammo is a touch above the mid quality ammo's. I shoot Wolf Match extra which is the same quality level as SK SP. Fortunately this shoots decent in my Anschutz and I paid $9 a box last year.
22rf ammo is funny stuff. One lot can shoot awesome in a gun or not so well.
My best personal example is having Lapua 22rf ammo tested at the Lapua test facility.
I found one lot number of Polar Biathlon, which is two tiers lower that their best which is X-act, and it shot "almost" as good as the best lot of X-act. Back then like 9 years ago the PB was $12.50 a box and the X-act was $19 a box so very high quality ammo.
We also found lot numbers of both those ammo's that didn't shoot the best in my gun. It's an odd thing because one would think that spending that much on ammo would produce consistent results in the higher quality rifles, nope??!!
The caveat is one has more chance of the ammo shooting well as the price goes up. In my example the worst lot of X-act shot better than the worst lot of PB. My gun didn't like any of the CenterX which is odd?? Back then it was $10 a box.
The big box store bulk ammo often doesn't shoot well. The worst I've seen 175 fps ES with it, 2.75" groups at 50Y, and about every 20 rounds the cartridge wouldn't even fire.
30-ish fps ES is about the best one can hope for with the best 22rf ammo and it can put down sub 1/4 groups at 50Y often. Though the ES becomes more apparent as the distance increases and can get pretty bad by 300Y.
I have a feeling that the 22rf with better ammo tested in his gun would still be similar if the Panthera was tuned in well. That's why I thought it would be interesting to see.