So I'm new to all this precision/competition stuff but in my world 30 sec (1/2 min) at 1078 yards is
sin 0.008333(1078*3)
=0.47'
If you can shoot at 1/2 min thats 0.5' at 1078yards right or am I off track?
3" at 1078yards would be around 15 sec or (1/4 min) right?
Just trying to get this all straight.
Treebutcher you have got the math straight. 60 minutes of angle in a degree, etc. Half a minute of angle is 0.47 feet at 1078 yards, or 5.64 inches.
The math is made much easier using the approximation that "one minute of angle is one inch per hundred yards of range" (not exactly correct, it's actually 1.047", but "an inch" is oftentimes the right approximation to use). Sometimes this is called a "shooters minute", or sometime "IPHY" (an awkward abbrev. for "inch per hundred yards")
So ten inches at a thousand yards is (about) a minute. Half a minute at a thousand is five inches. Three inches at a thousand yards is less that a third of a minute.
At 1078 yards (not a standard shooting distance either in yards or in meters), three inches is less than 0.3 MOA
It so happens that the standard US "Long Range" target, which is used at 800, 900 and 1000 yards, uses a 10" diameter X-ring and a 20" diameter ten-ring. It is a fairly challenging target to shoot at using iron sights. A good shooter on a day with easy conditions can expect to get a majority of his shots in the ten-ring, with about half his shots going into the "X". Getting a "clean" score (15 shots into the ten, scoring 150 out of 150) is not certainly unheard of, but you can be pretty proud of yourself when you do it. I've never done it.
For F-Class, which in many ways is "prone benchrest", there is an F-Class version of the target - basically every scoring ring value is moved "one in". So on the "LR-FC" target, the 20" diameter circle scores nine points, the 10" diameter circle scores ten points, and an added 5" diameter ring scores an "X". This target has been in use in the USA for several years now, you can check out what sorts of scores are being fired in US F-Class matches, and you can see what sorts of records are being set (see the US NRA web site). Generally it seems that the F-Class target for an F-Class shooter is a little bit more difficult (score-wise) than the iron sights target for an irons shooter. At a match where the top iron sight shooter might score say a 150-9X, the winning F-Class score might be 148-7X (to give you an idea of the relative difficult level).
While "clean" scores (all tens) in 1000 yard F-Class are doable, they too are pretty worthwhile. And while you sometimes see impressively high "X" counts, I don't think anybody has ever shot 150-15X at 1000 yards (that would be fifteen out of fifteen shots into a 5" circle).
The F Class World Championship was fired in July 2009 in Bisley. The results can be found on the
NRA-UK web site, they shot on the same target mentioned above except that it was a five-point target system, i.e. the ten inch ring scored five points and the five inch ring scored a "V-bull". (Americans and Europeans like targets with tens and Xs. Brits Canadians etc like targets with fives and Vs. Same general idea though!)
Have a look at the scores fired by the best F-Class shooters in the world, you will see that very few shooters managed to get half of their shots into the 5" V-ring.
