Variable speeds don't start to increase the frequency of "flyers" until you start shooting past 50 yards with 22rf rifles/ammo.
IMHO, the biggest issues for accuracy show up with "sloppy" chambers and too much headspace.
22rf shooters can be extremely serious about accuracy, and some will chronograph their loads at different ambient temperatures and elevations, then record the deviations and extreme spread differences. I understand this reasoning and used it myself when shooting CF matches.
Most 22rf shooters understand the importance of "tight, properly aligned to the axis of the bore chambers"
When I had my 22rf match reamer made up, I sent a blueprint to the company making up the reamer. The dimensions are a few thou tighter, bordering on minimum SAAMI specs for all dimensions, including rim/body/throat diameters and lengths.
When I seat a cartridge, I can feel the bullet engaging the leade and being pressed into full battery when the block on my Martini comes to full battery position. The tight chamber dimensions allow this to happen without safety issues, just like it does in some CF match rifles, where a similar practice is followed.
"FREEBORE" is not necessary and extremely detrimental to accuracy, IMHO, with lead bullets, especially when there is no control over the priming/propellants.
I find that engraving the bullet, by slightly forcing it into the leade, is one of the best ways to ensure consistent accuracy with a broader range of manufacturers ammunition, than to allow the bullet to jump before engraving.
Back in the day, when black powder was the common propellant, free-bore was necessary. The manufacturers and shooters compensated for the free-bore by using cartridges with very long necks to hold long bullets until they engaged the leade. This isn't necessary today, so shorter throats are OK, IMHO.
Harry Pope figured this out, along with others, during the late eighties when BP cartridges, including the 22rf, were becoming the norm over muzzle stuffers.
They were curious as to why they could often get "rifled muzzle loading rifles, using patched bullets" to shoot more accurately than cartridge-type firearms. It was also in this period when they were finding their tech often wasn't up to consistent bullet to bore fit and a myriad of other issues created by priming, propellants, metallurgy of cases/bullets, and methods of lubrication came into play, when extreme or even good accuracy was demanded.
22rf has come a long way since those days, especially when it comes to standardization procedures, metallurgy, priming, propellants, lubrication.
It still has a lot of variables, as do the rifles themselves.
It's the main reason I never got "seriously" into 22rf match shooting.
There just wasn't enough shooter ability to control consistency from firearms, if you bought them, and especially ammunition.
22rf ammo from the same manufacturer, but different lots, can be as different as night and day, but often, very consistent, as long as nothing else has changed.
My most accurate 22rf rifles had tight chambers and tight bores.
