Re: Anybody have any ideas?
"one will be under a quarter inch and then 4 groups in a row will be close to and inch and a half."
Actually, it isn't "magic" working against you. The close shooting groups are just the laws of chance or, as the math gurus call it, "a statistical anomally." Meaning your "great groups" are likely just the result of chance and is NOT representitive of the grouping qualities of that load.
Toss a handfull of rocks at a wall. Note that somewhere on the wall the you can easily find several impacts quite close together but that means nothing to do with the overall pattern.
Some of your groups will show that same kind of random chance as well. By pure chance, any 3 or 5 rounds may cluster together but the real accuracy is displayed by the widest shots in the total number fired. Thus, larger groups are usually showing what our rifle is doing with that load, not an occasional small group.
This is especially true if we are test firing a sequence of loads for groups. If the charge (or seating) steps are small, large groups are unlikely to suddenly shrink tremendously and then get much larger immediatly after any one test load. Only groups tending to shrink as we approach a good point and then tapering back out as the charge is increases is likely to "prove" anything. I prefer to test 3 shot groups in no more than .3 gr. steps to show the group progression better. Even then, I'm not surprised to later find some small groups aren't repeatable.
I consider the size target I can hit - everytime - is my true accruacy. Averaging serves to smooth out the effects of the wider shots and merge them into a smaller mathmatical composite. IMHO, that's not a really good thing to do, I can't hit anything with math, I have to use my rifle. So, for me, averaging becomes a means of happy-side self delusion.
Last edited by boomtube; 07-09-2009 at 09:23 AM.