on the part of the shooter to remain focused and consistent can result in a bad shot. It's common to use a benchrest or a vise when evaluating ammunition or a weapon for accuracy in order to eliminate human error. Measurements Since adjusting the point of impact to match the point of aim is relatively simple with any type of adjustable sights, the primary goal of accurizing is to increase the precision of the firearm, which is generally measured by looking at the dispersion of a number of shots fired at the same point of aim. An ideal group would be one where all shots land in a hole no larger than the diameter of a single bullet; this would indicate zero dispersion. The most common way of measuring groups then is to measure the edge to edge distance of the farthest holes, and subtract the bullet diameter, which gives the center to center or c-c measurement of the group. This can be expressed in linear measures (a 30 mm group at 100 m, or a one inch group at 100 yards) or in angular measures (a milliradian or MOA group). Groups for rifles are traditionally shot at either 100 meters or . At 100 yd a minute of arc equals , and the one MOA group (approximately 1/3 or 0.3 mil) is a traditional benchmark of accuracy. Handguns are generally used at closer ranges, and are tested for accuracy at their intended range of use. Also of importance is the number of shots fired. Statistical likelihood says the fewer shots that are fired, the smaller the dispersion will be. 3 or 5-shot groups are acceptable for zeroing the sights and rough accuracy estimates, but most shooters consider 10-shot groups to be the minimum for accuracy comparisons. Defining accuracy Even defining accuracy can be problematic. An example of this can be shown by the following tests, run by Performance Shooter magazine in December, 1996. The magazine was testing seven brands of .38 Special wadcutter rounds in three different revolvers, a Smith & Wesson Model 686 and Model 52, and a Colt Python Target model, with six, five and eight inch long barrels, respectively. Ten groups of five shots were fired and measured from each revolver with each ammunition. Click on the image at right to see a larger view of the graph of average group sizes for each type of