Jock, as you know, i spent a good bit of time evaluating the accuracy required to win Field Target matches, which are perhaps the most difficult competitions currently being conducted using airguns. After lots of mostly firsthand observations of the (relative) capabilities of various air rifle models that have been popular for FT use, as well as careful observations of the conditions and target sizes/placements in the matches, i came to the following conclusions:
a. The most demanding shots with regard to intrinsic accuracy are the longer shots. I thus perform most testing at over 50 yards. That said, i have observed over and over that pellets fired from HIGH powered airguns are typically not very stable at close distances such as 10-15yds, and have noted on many occasions the groups fired at 10yds are often as large, or larger than those fired at 20-25yds. This condition exists with firearms as well, but the distances are normally 50-100yds or more when the bullets stabiliize. I reckon the reason is the same tho ... the projectiles often yaw, and take a bit of time (distance too stabilize. The effect is oppisite with LOW powered airguns, where groups can be VERY tight at 10yds, yet fall appart and widen beyond predictions at beyond 45yds, presumable due to destabilization resulting from being overspun for the remaining velocity. Nonetheless, folks that try to extrapolate group sizes using the normal means usually get it wrong at the real close distances.
b. Although i'm aware that there is a difference between ACCURACY and GROUP size, i have found the distinction is not all that large when evaluating gun performance under best conditions. Thus, while accuracy strictly means the ability to put a shot into an exact location, while grouping means to put shots close to one another, without regard to the exact location, i have found the ability to group tightly is a strong indicator (for most good airguns) that one can also place a shot closer to the desired point with a gun that groups well. Of course some guns DO vary in the ability to put the first few shots where the next will go ... especially springers, and some guns vary from day to day, or with temp, etc., but all in all, the ability to group well is STILL a good indicator of accuracy potential.
b. Its more appropriate to discuss the intrinsic accuracy capability of the rifle/sight combination as used under ideal conditions (benched, wiindless, good light, competant shooter). Once this is established, it can then be assumed the field conditions, mental errors, etc. will play to slightly or greatly reduce obtained acccuracy too a greater or lesse degree, depending on the individual shooter's capabilities and efforts.
d. There is considerable difference in the general performance of winning OPEN CLASS rigs compared to SPRING CLASS rigs. It appears that spring guns capable of delivering 2moa can often win FT matches in the SPRING division, while it seems to require around 1.5moa or better for the open class win.
c. At a certain level, the very finest shooting individual guns of a type all seem to shoot at nearly the same level under ideal conditions, with pellet quality and compatibility seeming to be the largest controlling factor. The best grouping for exemplars of a type seems to be around .8moa using the best available pellets. I feel a minimal standard for evaluating group capability is to average the ctc results of five consecutive five shot groups.
d. A good test of intrinsic ACCURACY is to fire one shot each at the bull center of five individual targets in the afternoon, then wait til the next morning and fire five more at the same target bulls, noting any and all shifts, then fire five more at mid-day, wait an hour, and fire the rest of the 25 total shots. Thoigh this test also introduces a strong ewlement of shooter ability into the test, its still worthwhile, and the "shooter element" can be smoothed by first taking a number of warmup shots using a different rifle from the same distance and at a simlar target until one feels comfortably steady.
e. In the end, i feel ANY airgun that can consistantly put most (49/50) of its shots inside a a 7/8" target circle at 50yds is capable of winning any OPEN CLASS airgun match i've seen or heard of, assuming the shooter is highly skilled and motivated. I estimate the target circle size could be opened to 1 1/16" for the SPRINGER class.
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