This is prompted by Saeed's marvelous work, but not wanting to distract, my comment comes in a separate topic.

For 2 years, I have been testing 22 Shorts for accuracy, fired from rest using an old-time (but nearly new) Stevens-Pope target rifle (made in 1904). The rifle is chambered and rifled specifically for Shorts. My goal is to see if modern Shorts are as accurate as those of the 1897-1914 period. The standard of that period was that all shots (at 25 yards) had to hit completely inside a circle 0.700" (17.8 mm) in diameter. That is the diameter of the American 10 cent coin. The goal is easily achieved with many types of 22 Long Rifle target ammunition, but how about Shorts?

I fire at a range of 25 yards, outdoors but in a sheltered spot next to a wall. I fire 2 shots at each bull, measuring the outside-to-outside distance between the lubricant smudges and the score of each shot.

When testing Lapua Rapid Fire Shorts, I measured velocities and at the same time, recorded the point of impact of each shot, shot after shot, for 74 consecutive shots.

The first thing I observed was the obvious. All the higher velocity shots impacted the target at points higher than any of the lower velocity shots. That is gravity at work. Higher velocity = shorter time of flight.

The second thing was that velocities varied greatly with the first 30 shots and then settled down. Velocities from a clean barrel were higher than those fired later. After 30 shots, the standard deviation of velocities decreased, 2-shot group measurement sizes decreased and target scores increased.

Serious smallbore target shooters have long held that it takes 1 shot per inch (or per 25 mm) of barrel length before a rifle will hit center after center, shot after shot. My test with Lapua Rapid Fire Shorts verified this belief.

I have somewhat verified this with Eley Match... but used just 15 shots to get the barrel to "settle in." The 1st 15 had a SD of 7 (which is good) but a variation of 31 from min to max. the second 30 had a sd of 5 and a variation of 25. More data need be taken, but this is a start on 22LR. As to accuracy, can't tell yet. On the box the stated velocity is 1054 and the average with the 30 shot sample was 1055, so not far off. Used a somewhat maligned Magnetospeed on a 1970 Anschutz 1407. HTH