Jerry can play with "barrel specs" to his heart's content, a tuner is something that has an immediate and dramatic effect. Yes, my friends, do not underestimate the effect a naked, whippy barrel has on your target results. You all would have eliminated this SK RM from your testing based on the first 50 yard groups, right? But lo and behold, the ammo was just fine for use... It simply didn't suit the naked barrel, but we can
make it work, with a tuner. When you go naked,

, not only do you have to find a good lot of ammo, you have to find one that suits your barrel. The odds are stacked against you, and you'll be passing over plenty of suitable lots.
Jerry's "barrel specs" and your tuner are addressing two separate issues and shouldn't be confused.
To make a comparison to the center fire world that people may be more familiar with:
A tuner is the rimfire equivalent of playing with seating depths and charge weights to find the most accurate node for your rifle/barrel. Center fire, we tune the ammo to our rifles. Since we're not (yet) loading custom RF ammo for our rifles, the tuner is instead tuning the barrel to fit the factory ammo you're feeding through it.
Not to speak for Jerry, and I don't know what is specified differently than a typical RF barrel that he's been working on, but different barrel specs would be handy in stabilizing the bullet more effectively, and getting the most out of published ballistic coefficient's for the bullet's we're already using. His barrel specs for RF would be the centerfire equivalent of shooting the recommended barrel twist for a given bullet weight/profile.
While a tuner does a great job of fine tuning ammo to the right 'node' and will improve accuracy at 50y, it's not going to do anything to improve the BC and ultimately the efficiency that it cuts through the air and bucks wind. There's testing currently being done that is suggesting that changes to typical barrel specs are providing substantial down range benefits without a downside at 50y.
Will these specs make a bit of different to 50m benchrest guys? Very unlikely - that game is well researched and has ammo mass produced that is capable of out shooting the shooter in most cases.
Will it help a PRS/ELR shooter? Absolutely. If we're able to take advantage of published BCs in the .172 range (Lapua), instead of the .120 - .130 we're actually seeing in the field, it will be significant. The ballistic calculators show it to be in the neighborhood of 20-30% less wind drift and and 10% less elevation required (using the same match grade ammo we're using now). Those are pretty big numbers.
Now, (and sorry), to derail the thread a bit further because this stuff is neat to explore.
If I was a betting man, I'd wager on two things:
1) No changes are going to be made to the RF world if you're shooting RF BR 50m-100m.
2) Long range rimfire is going to look a lot different within 2 years at "higher" levels of competition (ELR/National Level Matches). The first step, you're going to see slightly longer barrels with much faster twist rates. That alone is going to be significant even with the factory ammo we're shooting. The second step we're going to see is a heavier bullet pushed to standard velocity speeds - if I had to guess, I'd think it'd be about a 48-50gr lead bullet - think Lapua CX, elongated by about .140" split evenly between the bearing surface and start of the ogive. Slight bearing surface increase should add some stability/consistency while in the bore, and a slightly more tapered round nose should increase the published BC ever so slightly.
Despite the claims and concerns, I think reloading 22LR is on it's way. I've been contemplating this quite heavily since the Cutting Edge/Shot Show announcement. While I've come to agreement that a solid copper/light weight bullet @ high velocity is unlikely, heavier bullets with an even slight improvement to BC are the next logical step.
How I'd do it?
Take apart high quality factory ammo (Eley or Lapua, whichever has the harder brass but consistent primers)
Trim brass back .140" (match elongated length of new bullet)
Re-use powder pulled from factory ammo.
Have custom swage die made up for new bullet and form the same way the airgun guys are making their slugs (awesome video from the other thread, thanks!)
Crimp them with a custom crimper (similar to the "plier" type crimpers in the 22lrreloader.com kit, but sized for the shortened brass and made to better standards).
Figure out lube
I'd charge the loads to shoot somewhere between 1040-1080 through a 22" 1:8 or 1:9 barrel.
I'd anticipate a 50gr bullet at 1040fps in a 1:9 barrel to be pushing a G1 BC of around .200. It's absolutely a guesstimate, but with Lapua publishing 0.172 G1 BC for a 40gr shorter Center X round, I'm thinking it would be close. I have little doubt that maintaining a 30-40 ES out of rebuilt factory ammo is possible if a case with quality primer is used.
I'd guess that by ShotShow 2022, Lapua is offering a factory round similar to what I've described above. Vudoo has already been openly discussing the faster twist/longer barrels and their work with both Cutting Edge and Lapua.
And after all that?
Throw a tuner on the end of your barrel to make it even better.
This is going to be a great couple years ahead.