So our neighbor loaned us his really nice varmint rifle complete with (not yet illegal) folding bipod. The rifle is chambered for "HMR .17" cartridges - Hornady Magnum Rimfire .17 caliber. They look like teeny little baby rifle bullets. I'd never heard of HMR .17 before I saw this rifle, but it's a heck of a good little cartridge.
Trying to sight the rifle in has been tough. The scope has 1/4 MOA click dials for adjustment. (1 MOA = 1 "minute of arc" = 1" deflection at 100 yards) So to adjust it any real amount you have to sit there for like two minutes clicking the little dials around. And at first the scope was so far out of whack that we couldn't hit anything at all.
But by sheer trial and error we're getting it sighted in. In my most recent target that I did this afternoon about 6, I managed to land all nine shots from a single magazine within the "9" circle on a target. Here's the picture:
The pen is five inches long. The "9" circle is 4 inches in diameter. There was a light leftward wind when I was shooting, which may explain the leftward deflection of most of the shots. The distance from the target was regulation 100 yards. (We actually went and measured out 10 thirty-foot segments with a tape measure to get the distance just right.) And yes, I know there are 13 holes in the target - the extras are the tail end of the previous magazine.
Inside a 4" diameter circle at 100 yards is not that great. I'm essentially shooting 2 MOA at 100 yards. At 300 yards, 2 MOA would be a circle a foot in diameter and at 600 yards (not even really long range by rifle standards) I'm just barely keeping inside a 2 foot circle. And I'm at the current limits of my ability.
As you can see on the target, when I get lucky the rifle can put bullets almost through the same hole. This from 300 feet away. It's obvious that I'm quite a bit less precise than the machinery I am using. A person who's a good shot using could probably shoot 1/2 MOA accuracy or even a bit better, which would mean putting all the holes inside the "X" section of the target, which is the 1" diameter circle centered inside the "10" circle.
Really good snipers shoot 1/2 MOA or less. The most famous sniper ever, US Marine Carlos Hathcock, actually made a confirmed kill from 2500 yards using a .50 cal BMG machine gun set up to fire single shots - though he claimed it was luck. 2500 yards is 7500 feet, or just more than one point four miles!
Still, a 4" diameter spread at 300 feet may be enough for prarie dogs. Though in the end it doesn't matter much to me, as I refuse to shoot them. It's amusing paradoxical that I'm happy to waste several hours sighting in a rifle, but then I won't use it for its intended purpose. That's me, your typical gun-loving pacifist...