Most serious smallbore shooters spend a significant amount of their resources - time and money - in testing batches of rimfire ammunition to find out what suits their rifle. Given that handloading rimfire ammo is not a practical proposition, it is not possible to tune the ammunition to suit the rifle as centrefire shooters can do, so the hunt is on to find a batch of ammo that seems to suit the rifle.
Fifty years ago, when Tenex ammuntion first set the benchmark standard for smallbore accuracy, it was an almost unbelievable ten shots into one inch at 100 yards - which was quite acceptable as the standard for a centrefire rifle in those days. Not today however. With the current state of ammunition components and the availability of rifle barrels and, particularly, rifle actions made to increasingly exact engineering standards, half an inch at 100 yards is a minimum expectation for any centrefire rifle with pretentions to accuracy. Quarter inch accuracy is increasingly the definition of "accurate". But the standard of quality for Tenex ammunition - still considered the best available .22 rimfire ammunition - is still ten shots into one inch at 100 yards.
Eley, and other smallbore ammo makers, have invested heavily over the past 50 years to improve their ammunition. The main effort of these manufacturers has been to tighten up the tolerances in their manufacturing process in the hope that tighter tolerances will lead to better accuracy. The result has been better consistancy, with Eley's pre-emininance being challanged by the likes of Lapua and RWS, but significant improvements in accuracy have been hard to win. In fact, there is a large body of opinion that rimfire ammo quality - Tenex in particular - has gone backwards over the past 30 years. Ah, the good old days of the paper boxed Tenex, I remember it well.
Whilst rimfire ammo manufacturers have strived to improve the accuracy of their product over the past 50 years, it can be argued that rimfire rifle makers have not. The barrels are still six or eight grooves with bore diameter .217", groove diameter .222", a 16" twist and a chamber dimensions which have settled on those developed by Winchester for their 52D rifle over half a century ago. "Improvements" in .22 rifles have been largely cosmetic, focussing on the adjustability and availability of colours of their stocks. Why? because it has been generally acknowledged that "the problem" is with the ammo, not the rifle.
Some may argue that barrel tuners have been a great recent innovation in rimfire shooting. It should be remembered that Art Cook was using a barrel tuner when he won Olympic gold in 1948. Barrel tuners have been around a long, long time. But if barrel tuners were "the answer" then why do we still have "the problem"? While they do work, they seem to need adjusting if the ammo batch is changed, or the temperature changes, or the pressure changes, or there is an 'R' in the month. Spending your life testing ammo to find a good batch is one thing - spending even more time fiddling with your barrel tuner, hunting the elusive accuracy node, is quite another. Our time on this earth is limited. The problem is that barrel tuners are poorly understood, with very little good theoretical or hard experimental evidence to give us the broad picture of what is going on when we add weight to the barrel. Without that broad picture, barrel tuners are at best a triumph of hope over necessity, with ignorance slumbering undisturbed.
So, as things presently stand, there are some people with some strong opinions about what makes a rimfire rifle shoot. Most people don't have a clue about what makes a rimfire rifle shoot - and when they ask the guys with the strong opinions for the facts to back up their notions, the "facts" either do not stand up to scrutiny or there is a sudden vagueness regarding their provenance.