那么M24的精度标准。。。"The average mean radius, calculated using 5 targets of 10 shots each, shall be less than or equal to..." 1.1MOA,相当于Max Spread ~= 3.3MOA,这是5个10发组的平均值,要注意,10发组的散布一般是5发组的1.3倍。。。换算成我们常用的5发组平均最大散布,相当于2.5MOA。
而M110的的标准居然高于M24:"The average mean radius (AMR) (see 6.11), of each shot group shall be not greater than to 0.68 inches at 300 feet. All targets shall be fired on using M118LR ammunition or equivalent, using five (5) round groups." 那么AMR=0.68MOA,相当于Max Spread ~= 2.1MOA。但是这个标准写的很有问题:每个5发组都必须满足这个标准,也就是多个5发组的最坏值必须满足这个标准?要注意,平均值和最坏值是完全不同的概念。。。可是它又没有说一共要打几组?这岂不是不停的打下去,成绩就会越来越差?恐怕只能把这个当作5发组的平均值来理解
“The distance between the mean point of impact of each shot group,
both unsuppressed and suppressed, shall be not greater than 1.1 inches at 300 feet. The distance
between the mean point of impact of the combined unsuppressed shot groups and the combined
suppressed shot groups shall not be greater than 3.14 inches at 300 feet.”
对于半自动必须同时考虑Accuracy和Dispersion。大家测一把半自动准不准,不能只看group紧就行了,要镜子精密归零,然后从冷管连续25发一直打到热,把5组里零点的游动也考虑进去,看总体25发的POI和POA的差距,也就是Average Distance to "Point of Aim",这才是最综合有用的数值