Pistol Shot Group Scoring
- Thread starter JonnyP
- Start date
OldShooter
New member
I don't have a source except that everyone wants to shoot 1.5 inch groups at 25 yards and this is a means to achieve that. Personnally I don't exclude anything and therefore my grougs generally suck, but I can hit COM at 50 feet.
He was being sarcastic. He needed an emiticon. He also said the best way to shoot a 1" group was to keep shooting 'til 3 holes formed a 1" group and ignore the rest.
Group size includes all the rounds you shoot.
I believe it was Mas Ayoob, though, who suggested that one can get a pretty good idea of the intrinsic accuracy of a handgun by shooting a 5- or 6-shot group, then measuring the closest 3.
The more shots you get in any group, be it rifle or pistol is going to give you a more accurate ideal how that gun shoots.
Take high power rifle, or bullseye pistol. Shoot three rounds isnt gonna tell you what will happen in a 10 shot string. You want to see what a gun will do, shot 10 or 2o rounds, dont throw any bad or good shots out, count them all.
Take high power rifle, or bullseye pistol. Shoot three rounds isnt gonna tell you what will happen in a 10 shot string. You want to see what a gun will do, shot 10 or 2o rounds, dont throw any bad or good shots out, count them all.
If you want to truly test the accuracy of the pistol, get a Ransom Rest.
If you don't have one, or don't have access to one, get thee to a range.
Put up a target at 25 yards--one with a clear, well visible aiming point.
Now, sit down at the bench. Build up a good rest with sandbags. You should build it with as much support as possible. The bags should NOT touch the barrel, slide or action of the handgun in any way.
How many rounds to shoot? If you have a magazine capacity of under 10 rounds, shoot two, five round groups. If you have a revolver, two cylinders full. For mag capacities over ten rounds, fire one full magazine.
Concentrate of firing the most accurate shots possible. Remember the basics and make each shot the best shot.
Afterward, find the outermost shot on both sides of the group. Measure from each hole, from the center of each hole, to the other. That's the group size.
A note to remember--handguns sometimes get rounds they do NOT like, and they will puke them all over the target. Loose groups may be the fault of the load.
If you don't have one, or don't have access to one, get thee to a range.
Put up a target at 25 yards--one with a clear, well visible aiming point.
Now, sit down at the bench. Build up a good rest with sandbags. You should build it with as much support as possible. The bags should NOT touch the barrel, slide or action of the handgun in any way.
How many rounds to shoot? If you have a magazine capacity of under 10 rounds, shoot two, five round groups. If you have a revolver, two cylinders full. For mag capacities over ten rounds, fire one full magazine.
Concentrate of firing the most accurate shots possible. Remember the basics and make each shot the best shot.
Afterward, find the outermost shot on both sides of the group. Measure from each hole, from the center of each hole, to the other. That's the group size.
A note to remember--handguns sometimes get rounds they do NOT like, and they will puke them all over the target. Loose groups may be the fault of the load.
I like Carlos Hathcock's method of teaching people to be accurate shooters. He basically took them out to the range and after they fired their first shot, he told em to pack up, clean their weapon, he would see them the next day.
Yep, . . . one shot a day, . . . and the shooter got 24 hours to think about how, what, hmmmmmm, . . . of that shot. They also kept a log book of weather, time, temperature, wind, etc.
He would after a while start making them also call their shots as to where they thought this one would go according to external effects.
His method produced a full crop of excellent snipers, . . . not reactive shooters, . . . but I suppose the technique could be adapted to reactive shooting also.
I know myelf, . . . I sometimes get frustrated with my shooting on a particular day, . . . and I just burn ammo for the rest of the session, . . . and while it gives me practice in cleaning my weapons and policing up spent brass, . . . it usually doesn't do much for helping my accuracy.
I've been thinking about doing the "one a day" thing, . . . just haven't started it yet.
May God bless,
Dwight
Yep, . . . one shot a day, . . . and the shooter got 24 hours to think about how, what, hmmmmmm, . . . of that shot. They also kept a log book of weather, time, temperature, wind, etc.
He would after a while start making them also call their shots as to where they thought this one would go according to external effects.
His method produced a full crop of excellent snipers, . . . not reactive shooters, . . . but I suppose the technique could be adapted to reactive shooting also.
I know myelf, . . . I sometimes get frustrated with my shooting on a particular day, . . . and I just burn ammo for the rest of the session, . . . and while it gives me practice in cleaning my weapons and policing up spent brass, . . . it usually doesn't do much for helping my accuracy.
I've been thinking about doing the "one a day" thing, . . . just haven't started it yet.
May God bless,
Dwight
Powderman,
The method you describe sounds good. However, doesn't that assume the group is relatively equally spaced around the aimpoint? What if all the shots are "grouped" in a nice tight fashion, say, within a 1 inch circle, but 6 inches to the right of the aimpoint? Assuming such a group was a result of me and not the gun or the ammo, I would call something like that a 6 inch group, not a 1 inch group.
Thoughts?
The method you describe sounds good. However, doesn't that assume the group is relatively equally spaced around the aimpoint? What if all the shots are "grouped" in a nice tight fashion, say, within a 1 inch circle, but 6 inches to the right of the aimpoint? Assuming such a group was a result of me and not the gun or the ammo, I would call something like that a 6 inch group, not a 1 inch group.
Thoughts?
Group size is a measure of the consistency of the gun/shooter/ammunition combination. It is not a measure of how well the sights are regulated on the firearm nor of the shooter's ability to make the bullets hit on the target where he wants them to.
Group size is simply the distance between the centers of the two shots farthest apart on the target. The fact that group may not be centered on the aiming point doesn't change the group size measurement.
There is an old target measurement technique that is not commonly used today called a shot string measurement.
A shot string measurement is the sum of the distances between each bullet hole and the center of the target. So if you shot 3 rounds and one hit was 1" from the target center (in any direction), the second was 1.5" from the target center (in any direction) and the third was 5" from the target center (in any direction) then the shot string measurement would be the sum of the distances or 7.5". One would say that the competitor shot a 7.5" shot string.
I've been doing something similar for a number of years. I calculate the center of the group (which is not necessarily the center of the target [aiming point]) and then calculate the average deviation of the shots from that center. That way, each shot (not just the two outliers) contributes to determining the precision (usually incorrectly called accuracy) of the gun/load/shooter combo, and the deviation of the group center from the aiming point (which is properly termed the accuracy) can be used to adjust the sights, if desired. Another nice feature is that the group can get either larger or smaller as additional shots are added - using the maximum spread, groups can obviously only get larger, which is statistically unsatisfying.
The method is to first measure the x and y distance of each shot from the aiming point. The group center is then the average x and average y, and the distance of each shot from that center is given by the good-old Pythagorean theorem. If you use targets that have a pre-printed grid on them the measuring part goes quickly, and a simple Excel spreadsheet takes care of the heavy lifting from there. I worked up a spreadsheet that also calculates the maximum spread (I, too, am looking for that magic 1" group) and a number of other statistics, and prints out a diagram of what the group looked like. It also has the ability to track and do stats on the velocities (speed, really) of individual shots for those times when I've also used the chronograph. These get stored electronically where they're easily retrieved for subsequent load testing and evaluation.
That's a 1" group - it doesn't matter (for the purpose of group size) where it appears on the target. You've described a situation in which precision (which refers to repeatability) is very good, but accuracy (which refers to how close an outcome is to its "true" value - in this case the aiming point) is poor. As an example of high accuracy but low precision, consider 4 shots that each strike exactly 6" away from the aiming point at 3, 6, 9, and 12 o'clock - the gun is apparently correctly sighted in (i.e., is accurate) but is not precise.
Achieving accuracy with a firearm is a simple matter of adjusting the sights - precision is another matter altogether and depends on the interrelationship of a multitude of factors, some of which are the bullet, load, firearm itself, and shooter.
The best-three-of-five is Massad Ayoob's way of determining a gun's accuracy, based on how accurately you can shoot it. Shoot five rounds from a rest; all five are how well you can shoot the gun, and the best three are an approximation of how well the gun will do minus the human element. I generally go best six out of ten, because I think it gives a better view of where the gun is grouping, than does only five rounds; I'll shoot five, and see three on the right side of center and two on the left of center, and figure that's centered. After shooting five more, I see seven on the right, and three on the left, and I know the gun is shooting right of center.
kodiakbeer
Moderator
I was joking! Throwing out "flyers" is something like calling a "Mulligan" in golf - it's cheating.
tackdriver
New member
That is unless you make a living reviewing pistols for gun rags. If you can't do that you write, "acceptable for defensive purposes for which it was intended."
kodiakbeer
Moderator
A lot of pistols I've owned have thrown one flyer per mag at first. That's because the lock-up is often a little different with the first manually chambered round. That tends to go away pretty quick after some shooting marries up the parts.
Gun writers using that cliche' about "acceptable" combat accuracy is a little tiresome, but that doesn't make it untrue. I'd rather have a loose weapon that shoots 8" 25 yard groups than some fussy target pistol that may jam if some lint gets in the action.
My main carry gun is a very accurate Kimber compact - or was with the original sights. I replaced them with a huge glowing fire-dot front, and a half circle rear sight. A beer can at 25 yards is pretty safe with those sights, but I can hit a chest sized target every time and in any light. And I can get on target much quicker than with traditional sights.
Gun writers using that cliche' about "acceptable" combat accuracy is a little tiresome, but that doesn't make it untrue. I'd rather have a loose weapon that shoots 8" 25 yard groups than some fussy target pistol that may jam if some lint gets in the action.
My main carry gun is a very accurate Kimber compact - or was with the original sights. I replaced them with a huge glowing fire-dot front, and a half circle rear sight. A beer can at 25 yards is pretty safe with those sights, but I can hit a chest sized target every time and in any light. And I can get on target much quicker than with traditional sights.
JohnKSa - Yes, I stumbled onto a lengthy thread at (as I recall) the AR15 Forum a while back discussing the military method, which I eventually understood to be pretty much the same thing I was doing, just a good bit more sophisticated. I can't seem to remember the name or any more of the details either, but I suspect there's a milspec for it and I'll poke around and see if I can find it.