For us hunters there is really only one group size -- the 1st shot from a cold barrel.

Multi-shot "groups" from some of my preferred hunting rifles would do all sorts of things that would make them useless for target shooters, like "walking", sometimes a "lot". That is, IF you did not wait for barrel to totally cool down, etc.

JLouis wrote on Sep 5^th, 2018 at 7:42pm:


Input to a rather simple statistical analysis. Nothing new, or even very novel.

svartkruttgris#369 wrote on Sep 5^th, 2018 at 9:47pm:


Please explain. What statistical analysis?

joeb33050 wrote on Sep 6^th, 2018 at 6:44am:


Old, old, technique. Fire enough "2-shot" groups, each with a common aimpoint (say on multiple aimpoints on one or more identical paper targets) and you can create several groups (2-shot, 4-shot, 6-shot, etc., etc.) by overlying multiple 2-shot groups. Analysis can proceed either graphically or numerically, adding stats analysis if you like.

Or, shooter could just walk down to target and label each shot in sequence. If numerical data, then various stat analyses can be used, if that floats your boat -- never did float mine. What I wanted to know, those individual "2-shot" targets, used together, gave all info I needed.

Has several possible real-life applications. How groups drift or open up as barrel warms up? Effects of different lighting conditions, especially on metallic sights? Temporal details of scatter during long shot strings? Means of verifying details of how much improvement or degradation has resulted from attempts to reduce POI shifts? Long term stability of group sizes? May also aid in understanding cause(s) of long term variations, without having to shoot up lots of expensive ammo, require hours of expensive range time, etc., etc.

On one much used hunting rifle (very small diameter rifle barrel on O/U combi gun) first two quick shots gave 2,0 inch group at 100M. Subsequent shots drifted reliably in direction and opened to 4-6 in group, so long as cold shotgun barrel not fired. Very different and more accurate information than from more than 2-shot groups. Also essential information for use on smaller critters where more precise accuracy was essential.

mes wrote on Sep 5^th, 2018 at 2:11pm:


In 2005, when I started my obsession with .22 Shorts, I began shooting at 50 yards and used Mean Radius and 10-shot groups as my method. I learned a lot, but it is very time consuming.  I'm an hydrologist by profession and use Excel every day, but it is still a lot of work.  The Army has used Mean Radius to evaluate ammunition since the days of the Trapdoor, but they have lots of help and helping is pretty good duty.

A series of e-mails with Brent Danielson led me to the 2-shots per target method, same target as we shoot in Winter League, as the most efficient way to evaluate .22 rimfires.  I've used it from the bench at 25, 50 and 100 yards.
You get 3 bits of data for 2 shots; score 1, score 2, and distance between shots.   

What Brent said is that .22 rimfires are so variable that you will use up your time, frustrate yourself, wear out your rifle and by the time you identify the brand & lot that works best in your rifle, the other guys will have bought up the entire lot.

Matter of opinion.
More than one way to skin a cat.

Aaron

Rebel wrote on Sep 6^th, 2018 at 12:53pm:


Yes, and a lot of cats that sometimes need skinning.