The Firing Line Forums - View Single Post - Do you need at least 10 shots to establish a valid group?

Loosedhorse · April 4, 2017, 06:50 AM

For me:

Typically 3 shots for a bolt-action, single-shot, and (probably) pump-action or lever-action. A cylinder-full for a revolver, because I want to check all the charge-hole/forcing cone combinations. Probably 5 shots for a semi.

The trouble with using larger numbers of shots, if your purpose is to get at the "intrinsic" accuracy of the firearm, is that it starts getting more and more likely that you will include some "random", non-recurring error that has nothing to do with the firearm (shooter error, unusual round, sudden gust of wind, etc.).

If you're using a Ransom Rest for handguns (and using it properly) at least that eliminates shooter error; I don't think there's an equivalent for rifles.

Now, if you're not testing the rifle, but the rifle/shooter combination, well, shoot as many as you believe you normally would at a single target, from the shooting position that you would normally be shooting, at the speed you would expect to shoot them.

April 4, 2017, 06:50 AM	#13
Loosedhorse Junior member Join Date: March 25, 2017 Posts: 115	For me: Typically 3 shots for a bolt-action, single-shot, and (probably) pump-action or lever-action. A cylinder-full for a revolver, because I want to check all the charge-hole/forcing cone combinations. Probably 5 shots for a semi. The trouble with using larger numbers of shots, if your purpose is to get at the "intrinsic" accuracy of the firearm, is that it starts getting more and more likely that you will include some "random", non-recurring error that has nothing to do with the firearm (shooter error, unusual round, sudden gust of wind, etc.). If you're using a Ransom Rest for handguns (and using it properly) at least that eliminates shooter error; I don't think there's an equivalent for rifles. Now, if you're not testing the rifle, but the rifle/shooter combination, well, shoot as many as you believe you normally would at a single target, from the shooting position that you would normally be shooting, at the speed you would expect to shoot them.