By design, or accident, the .22LR cartridge and bullet seem to max out for consistent accuracy at about 50m/yards. Beyond that, there appear to be random effects on bullet flight that open up groups very wide. Add wind that is variable and groups are very big, which is just the reality of light slow projectiles being pushed around by swirling wind.
At 50m/yards, matches are won and lost on ammo inconsistency within the same lot. We have all experienced the rounds that drop like a stone down into the 8 or 7 ring when the recoil in the reticle recoil indicated it should have been a 10 ring hit. And we see the screamer round that shoots high into the upper 8 or 7 ring, again with the recoil of the reticle indicating that was impossible, but yet it happened. This round to round inconsistency and the geometry of angles just magnifies the spread with distance beyond 50m.
But I hypothesize that the target spread we see at longer ranges is more than just trajectory from angles from the muzzle. I hypothesize that the .22 LR bullet suffers from poor aerodynamics and therefore what we see at distance is a sort of knuckle ball effect at increasing distance - there are random erratic movements of the bullet in flight because of the crudeness of its design, with its huge cannelure rings and blunt stubby shape, soft nose sometimes with micro nicks and dents, gobs of lube, heeled end, and the concave rear end.
Hypothesis: Basically the .22LR bullet aerodynamically sucks beyond 50m, and the cartridge design by accident prevents factory manufacturing consistency for tight ES and SD.
This is one of the most thoughtful posts on this forum in a while. There are very real limits on .22LR
accuracy, to use the term generically.
It has been reliably estimated that in testing facility conditions ten-shot groups at 50 m increase
on average by a factor of about 2.8 times at 100 m. In other words, on average ten-shot group size at 50m are 2.8 times the size at 100. Of course some rifle/ammo combinations will be a little better, some a little worse.
What that means is that .22LR accuracy is not linear. That is to say, group size doesn't simply double as distance doubles. Instead it gets worse as distance increases. If a minimum average group size increase is a factor of 2.8 (on average) as distance doubles from 50 to 100, if that factor remained valid for 100 to 200 then a 0.5" ten shot groups at 50 becomes, on average, 1.4" at 100 and 3.9" at 200 meters.
What makes .22LR even more challenging as distance increases, there's no reason to expect the factor would remain as low as 2.8 beyond 100 meters. All the factors that conspire to make ten-shot groups increase in size by a factor of 2.8 between 50 and 100, are still at work and would very likely produce results that see an increase
on average over a factor of 2.8.
Since .22LR performance is not linear, but only gets worse as distance increases, long distance shooters have been more than receptive to possible solutions to the long distance accuracy dilemma.
One of these have been offered in the form of faster twist barrels discussed briefly earlier.
Another has been novel ammo, such as the user-reloaded Cutting Edge bullets, about which posters on this forum were quite enthusiastic when their existence was publicized almost two years ago. Unfortunately, the Cutting Edge bullets, using CCI supplied pre-primed casings, don't appear to have produced affordable or significant practical benefit. Even "regular" ammo makers such as SK have introduced within the last few years ammo marketed as for "long range" --
e.g. SK Long Rang Match. This ammo still retains all the shortcomings of previous varieties of SK .22LR ammo in terms of quality and MV and other variation, but is different only in its initial higher MV.
Biologist's hypothesizes 50 meters as the maximum distance for consistent accuracy.
Without a good rifle and suitable ammo consistent, sub-MOA accuracy at 50 meters is a challenge. But as the 50 yard "1/2 inch challenge" on this forum shows it's doable with relatively modest rifles and non-lot tested ammo -- at least from time to time. Of course, it's often difficult to produce consistent performance.
Neverteless, and here I disagree somewhat with the hypothesis of Biologist, it
is possible at 100 yards/meters to have consistent sub-MOA accuracy with .22LR. At least three things are required. One is a very capable rifle. Another is excellent ammo, usually not randomly selected. A third is either an absence of wind or effective accounting for wind by the superlative use of wind flags.
Beyond 100 yards, consistent accuracy is too much subject to the vagaries of ammo consistency -- both in MV variation and otherwise -- and the unavoidable problems of winds when shooting outdoors, where even the slightest movement of air masses between muzzle and target make itself sorely obvious on target.
