"Standard" distance for measuring mechanical accuracy of the gun is 25 yards. That's done with a Ransom Rest, if you have one, or more commonly, sitting at a bench, with your hands resting on a sandbag, trying to eliminate the human factor. (Resting the gun on the sandbag can affect the point of impact as the gun bounces off the rest, and muzzle and cylinder gases can tear up the rest.)
If you are trying to measure marksmanship, instead of mechanical accuracy, then it depends on what you intend to shoot. If you are going to shoot rabbits, you need to be able to determine at what distance you can hit the kill zone of a rabbit. For self-defense, you need to know at what distance you can consistently hit a ten-inch circle (that being a rough estimate of the "stop zone" for a person). Many "combat shooters" can hold 10" at 100 yards, especially using braced positions like kneeling and prone.
If you intend to compete in the sport of Bullseye shooting, those guys work at 50 yards, and try to hit a 3.3" 10-ring, and a 1.7" X-ring. Gulp! Don't get too discouraged. Most people don't shoot all 10's and X's, do they? If you can keep all your shots in 10", then you can go out and have a good time participating in the competitions.
Well, my thought is this. I shoot srchery for fun as well as hunt. 30 yards is pushing the upper limit for energy for my equipment. For that reason, I seldom put alot of concentration on good groups past 30 yards. I have found that practicing at 30 yards makes 20 yards alot easier. I'm looking for a general range to practice from. Since I am new to handguns, I didn't know what the practical range would be. I shake alot using just one hand, so two hands or a rest are almost a must. I would like to try competition shooting, but I have been trying to get there with my bow for over a year and always seen to be too busy.
For "practical" shooting (the politically correct term for "combat" shooting), the standard distance is 7 yards. That's not for shooting "groups," though. The object there is to see how fast you can shoot a 10" group. The theory is that, in a gunfight, a fast 10" group is more likely to save your life than a slow 2" group.
There are some fun slow-fire accuracy drills that you can do at 7 yards, though. At 7 yards, you should be able to keep all your shots in one hole. Put one round into a blank piece of paper, and then use that first bullet hole as your target for the rest of your shots. You can also try dot shooting, which is a fun friendly competition for when you go shooting with your buddies, while building trigger control skills.
You can get lots of good targets at mytargets.com. Here's their dot shooting target, which I find to be a real challenge at 7 yards.
25 yards with a pistol is a good challenge, though. Except for stylized contests, there is not much practical reason to shoot one-handed. If you intend to go hunting, the braced kneeling position is useful to know (support-side elbow braced on support-side knee).
Hey Ruger! It sounds like we have a lot in common. I do most of my shooting at 50 yards with my .357 and out to 100 yards just to try to get my shooting form better. I know that I will never take a 100 yard shot in a hunting siutation, but it is still good practice in my opinion. I do the same with the .22 only at 25 and 50yards. Even 25 yards is a stretch for me when squirrel hunting with a handgun. For archery most of my groups are shot at 80 yards. My average group is now about 5 inches at 80 yards. Once again, I would never take this shot in the field, but it does help me with the close up shots. When I first started my groups were measured in lost arrows. I no longer shoot groups at 20 yards due to arrow damage. Anyway, I think you are on the right track as the main point of trying to shoot a good group at a long range is to improve your shooting form no matter what it is that you are shooting. Also, I tried a shooting stick for squirrels this season. It made a huge difference in my success rates. I was able to quickly get on target and make a clean shot. The one I bought is a cheap 3 section collapsible made by Allen. It was on sale for about $4. It can be adjusted to almost any height. I also use it with my .22 rifle when I'm hunting. It's just a thought to help you steady your shot in the field. These are just my opinions, and I hope they can help you.