—would your data from your 10/22 be approximately the same for all 10/22s, or do the characteristics of an individual rifle have an effect?
—would accuracy data from 10/22s translate across well-made .22s in general, or do such details as a longer barrel or different firing mechanism matter?
I have one operable .22 (the other one was my grandfather's and Dad taught me to shoot with it when I was 8, but it's not functioning and hasn't done since 1979), a cheap little Cooey that I rescued, painted, from a pawnshop in 1989 and repaired the finish; I have never tested it for group size on a range, but can reliably hit a pop can “a ways away” :)
The answer is, yes. :)
Seriesly, everything you mentioned has an influence, including shooter skills. There are plenty more variables involved, too. The trick is to start with some arbitrarily-fixed reference points, and then figure out ways to test some variable to see how much of an influence it has on overall accuracy. In most cases, the single biggest detriment to accuracy is the shooter himself.
In my case, I'm using my Ruger 10/22 target model because it has proven itself accurate enough to overlook any remaining flaws that still might reside in it. I'm starting with Federal Champion ammo because it's relatively cheap, highly rated by other .22 shooters, and I've seen its inherent accuracy in a number of my own weapons.
Now I'm working with gauges and gadgets to see what my rifle likes best about that particular brand. Tune in tonight for more details on progress so far. And the one thing that goes without saying, that I must say, is that everything can vary from gun to gun, brand to brand, round to round. But good data can help reduce those variables to below the statistical background noise.
After shooting a nice group, you need a way to measure it precisely. Then the size can be entered into a spreadsheet for later analysis, and the paper targets thrown away. Unless I shoot a once-in-a-lifetime group, and then I'll have it framed.
The first gadget is a .22 rim thickness gauge from Brownells. It's a simple, but highly precise, gauge that attaches to the jaws of a caliper, and measures the thickness of the rim.
I couldn't figure out why it included a neck lanyard until I started using it, and then realized I would not want to drop an $80 gauge and a $200 set of mid-grade Mitotoyu calibers on the floor.
So far, while checking 50 rounds of ammo, I've found that there are four different rim thicknesses present, but all vary less that .0001" from the most-common .0420" thickness. I won't know without testing, but I suspect that rim thickness may not have a noticeable affect on accuracy with this ammunition, and this Ruger.
After the rounds are shot, the groups need precise measurement. Enter another Brownells gauge, which are now permanently attached to my dad's 40-year-old first-generation Mitotoyu digital calipers. They aren't as consistent to the fourth decimal place, so I figured it was easier to just leave the jaws on full time.
Measure the two holes furthest apart, and there's your answer. This particular gauge can also measure 6mm and .30 caliber targets. The data goes into a spreadsheet, and the target can then go into the trash.
I've been spending the weekend making different variations of test ammo for a quick look-see. Starting with .222-sized Federal, I'll see how much that tiny variation in rim thickness matters. I'll also test two boxes of pre-1973 (no bar codes on the boxes) Sears generic ammo. Fifty rounds sized to .222", the other untouched. I have to remember to check the rim thickness for grins, and see how it compares with the Federal.
Pretty soon I'll have the best "pet load" for the Ruger identified. Then I'll start working on the subsonic brands, and see how much things can be improved. A whole lot of work will already be saved because it already appears that the Ruger prefers its ammo sized to .222". If that holds true, all I'll have to do is check rim thickness, and see how much of a role it plays with other brands. With that much data in hand, I should be able to characterize the best fodder for each CZ rifle, and for some of the handguns, too.
Right now, a lot of people are probably rolling their eyes over something so picky. You ain't seen "picky" until you get into benchrest shooting. I like blasting cheap ammo as well as anyone else, but I also enjoy the challenge of using my skill and resources to wring the best accuracy I can with my weapons I know are proven performers.
Evening ExGeeEye - well, an inoperable rifle is an opportunity imho. Check out rimfirecentral.com and you’ll find kindred spirits that truly enjoy resurrecting old .22s the clutches of disrepair. Regardless of the make, model and condition, someone on there has either the parts or the know-how to make the rifle run again, and occasionally you’ll find some withone with both. Good Luck in your quest.
RE: rimfire ammo, I’ll echo Win-Mag’s observation: try different brands at a known distance, from a stable rest or position and record the results. Sometimes you luck out and get appropriate, note: appropriate is what you decide it is, results. A peep sight helps, a scope even more if you have a rifle with a grooved receiver. Again - good shooting.