Some manufacturers of the higher priced rifles/handguns will send along a proof target with the item to demonstrate it's accuracy potential WITH THE CARTRIDGES USED FOR THE TEST. This doesn't mean you can grab up another makers cartridges or your own reloads and shoot the same results. Also, they have sophisticated setups to test the firearms in. Its just like trying to duplicate the results printed in the reloading manuals without benefit of the same testing apparatus and equipment.
Now, as to how many shots need be fired for a group. Most manufacturers, rag writers and informal target shooters feel 3 shots constitute a group, and they are perfectly correct in that statement. Heck, even 2 shots could be called a group! Most serious shooters (benchrest and competition) feel 5 shots are more appropriate to properly define a group and then there's diehards that feel nothing less than 10 will be sufficient. My personal inclination is that 5 shots should prove the capability of the firearm's grouping, with that individual tweaked load combination.
Most firearms aren't going to do squat in the grouping department when using rapid firing. You should allow the barrel to stay below a temperature that would make holding your hand on it uncomfortable. Taking a bit between shots certainly helps and then, you have to factor in ambient temps, also. Hotter days, longer cooling off periods.
Again, MOST firearms perform best grouping after a few fouling shots have been fired. Clean, dry bores shooting to the same POI (Point of Impact) are a rarity, but they can be found occasionally. As to how many shots are fired before the fouling buildup caused a decline in accuracy depends on how well conditioned the bore is and how much carbon is left over with the type of powder being used, plus how much guilding metal gets stripped off the particular type of bullet being used. Soft all copper jackets tend to foul the most.
Sub-MOA and MOA are bragging points and some shooters won't be satisfied with a firearm that won't shoot that tight of groups. Actually, for the hunter and infrequent target shooter, 1 1/2" to 2 1/2" groups are perfectly fine to cleanly take game at the ranges most are shot at.
Now, as to how many shots need be fired for a group. Most manufacturers, rag writers and informal target shooters feel 3 shots constitute a group, and they are perfectly correct in that statement. Heck, even 2 shots could be called a group! Most serious shooters (benchrest and competition) feel 5 shots are more appropriate to properly define a group and then there's diehards that feel nothing less than 10 will be sufficient. My personal inclination is that 5 shots should prove the capability of the firearm's grouping, with that individual tweaked load combination.
Most firearms aren't going to do squat in the grouping department when using rapid firing. You should allow the barrel to stay below a temperature that would make holding your hand on it uncomfortable. Taking a bit between shots certainly helps and then, you have to factor in ambient temps, also. Hotter days, longer cooling off periods.
Again, MOST firearms perform best grouping after a few fouling shots have been fired. Clean, dry bores shooting to the same POI (Point of Impact) are a rarity, but they can be found occasionally. As to how many shots are fired before the fouling buildup caused a decline in accuracy depends on how well conditioned the bore is and how much carbon is left over with the type of powder being used, plus how much guilding metal gets stripped off the particular type of bullet being used. Soft all copper jackets tend to foul the most.
Sub-MOA and MOA are bragging points and some shooters won't be satisfied with a firearm that won't shoot that tight of groups. Actually, for the hunter and infrequent target shooter, 1 1/2" to 2 1/2" groups are perfectly fine to cleanly take game at the ranges most are shot at.