mattt
Member
What is the correct way to measure your groupes.? Thanks
How to measure target groupes?
- Thread starter mattt
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rcmodel
Member in memoriam
Outside to outside edge of two widest shots, minus one bullet dia.
OR,
Inside to inside edges of two widest shots, plus one bullet diameter.
Or,
Outside edge of widest shot to inside edge of second widest shot.
Or,
Center to center of two widest shots.
Dial calipers if you really want to get down to a frogs hair.
rc
OR,
Inside to inside edges of two widest shots, plus one bullet diameter.
Or,
Outside edge of widest shot to inside edge of second widest shot.
Or,
Center to center of two widest shots.
Dial calipers if you really want to get down to a frogs hair.
rc
HorseSoldier
Member
Internet style: Measure widest to widest, divide by four or just take one bullet diameter, which ever is smaller. Add 100-200 meters to distance you actually shot target at. 
Steve H
Member
Digital calipers for nat's hair tolerances.
R.W.Dale
Member
Internet style: Measure widest to widest, divide by four or just take one bullet diameter, which ever is smaller. Add 100-200 meters to distance you actually shot target at.
Don't forget you must also make sure it's only one group of no more than 3 shots
Steve H
Member
I thought groups were ALWAYS 2 shots..................or at least the best 2 out of three
rcmodel
Member in memoriam
I've noticed an alarming trend in some gun magazine tests where the author says something like:
"The test rifle was MOA accurate right out of the box with this & this brand of ammo.
I threw out the two widest shots in the group and blah, blah, blah"
All this tells me is the guy can't shoot, or the rifle can't shoot.
One or the other.
I also see some published target photo's with group size noted on the target that had to be measured inside - inside of the two closest holes!
rc
"The test rifle was MOA accurate right out of the box with this & this brand of ammo.
I threw out the two widest shots in the group and blah, blah, blah"
All this tells me is the guy can't shoot, or the rifle can't shoot.
One or the other.
I also see some published target photo's with group size noted on the target that had to be measured inside - inside of the two closest holes!
rc
jon in wv they are being sarcastic about how many groups talked about on the net aren't what they seem to be. So many people claim a rifle shoots so well when in reality they cherry pick groups and often ignore a shot or two to make things sound even better.
I am comfortable with 3 shot groups.. 5 shot groups are a better indication of what YOU are capable of but the 3 shot groups are adequate to determine the abilities of the rifle... especially in hunting applications where you SHOULD NEVER be taking more than 1 to 2 shots in succession.
For a judgement on how good a shot you are, the more shots down range in that group the better.. if you can group a 5,10,or more shot group within a quarter inch of your initial 3 shot group with no fliers... you found the right rifle and the rifle found the right shooter.
For a judgement on how good a shot you are, the more shots down range in that group the better.. if you can group a 5,10,or more shot group within a quarter inch of your initial 3 shot group with no fliers... you found the right rifle and the rifle found the right shooter.
my tightest groups are always 1 ahot groups.
no, really, i dont see any reason why 3 shot groups are hated by tons of shooters. 5 shot groups are good, and 10 even better. one thing that is always left out of the equation is, the more shots in a group, the more thing have time to go wrong. the more shots you take, the better you are showing you can shoot. (or not shoot) the best way to fine tune rifle accuracy for handloading, if you want the utmost accurate round, is to strap the rifle down, and dont touch it to shoot it. take the human element out of the equation.
no, really, i dont see any reason why 3 shot groups are hated by tons of shooters. 5 shot groups are good, and 10 even better. one thing that is always left out of the equation is, the more shots in a group, the more thing have time to go wrong. the more shots you take, the better you are showing you can shoot. (or not shoot) the best way to fine tune rifle accuracy for handloading, if you want the utmost accurate round, is to strap the rifle down, and dont touch it to shoot it. take the human element out of the equation.
desidog
Member
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IMO the number of shots doesn't really matter...but for comparison sake, the norm is 3 - i'd also never omit counting a shot, unless it was clear shooter-error, when appraising a gun's accuracy. Basically, if you shoot three shots or six shots or sixty shots, the impact area should not move (unless the barrel heats up or you've got loose parts!) - so the group's diameter should be very similar. Once the paper is all torn up with one gaping hole from all X-amount of rounds I'd be willing to call that hole the group size. This is by no means official, but IMHO, the whole point of discussing grouping is to impart a gun's or shooter's ability for consistent accuracy. Of course, if you sent 100rds to make one hole, it is not as much fun since you don't know where they were landing exactly after the first few...so you can't work on improvement. Much like patterning a shotgun, the point is knowing where your lead is going, or rather, how much of a margin of error you can blame on the rifle when aiming for one particular spot. Of course, a good craftsman never blames the tools, but all rifles were not created equal.
3 round groups are too small. Even 5 round groups are too small to really determine what a rifle is capable of. 10 shot groups come close but the last time I checked everyone in the stats department claims a 30 round group is needed to truly have a gauge on what a rifle/shooter combo will do. Its impossible to rule out the human element no matter how hard you try. Its hard to rule out environmental influences from shot to shot and range session to range session. That said 3 shots doesn't indicate much. It can tell you at best how good a rifle can shoot and at worst nothing.
Think of it as flipping a coin. The odds of getting three heads tossed in a row is a lot better than the odds of getting 30 heads in a row. If you flip 3 heads in a row can you accurately state that coin is going to only flip heads for every flip there after? The bigger number of shots in a group the closer to an accurate representation you get for your rifle.
I won't always shoot 10 round groups and hardly shoot 30 rounders but try to stick to at least 5 and even then multiple 5 rounders.
I never have understood the reasoning why a 3 shot group is good enough for hunting. You still need to know where the bullet will hit. You may not need 1/4 MOA accuracy but you need to know what the rifle is capable of in your hands to know how far you can ethically take a shot. If I shot a single 3 shot group from a bench and it measured 1" at 100 yards it certainly tells me nothing about what I can and can't do in the field with that same setup. If anything hunting requires stricter test requirements to stay ethical. Paper won't limp away and die a slow painful death if you misjudged your abilities with the rifle in hand.
Think of it as flipping a coin. The odds of getting three heads tossed in a row is a lot better than the odds of getting 30 heads in a row. If you flip 3 heads in a row can you accurately state that coin is going to only flip heads for every flip there after? The bigger number of shots in a group the closer to an accurate representation you get for your rifle.
I won't always shoot 10 round groups and hardly shoot 30 rounders but try to stick to at least 5 and even then multiple 5 rounders.
I never have understood the reasoning why a 3 shot group is good enough for hunting. You still need to know where the bullet will hit. You may not need 1/4 MOA accuracy but you need to know what the rifle is capable of in your hands to know how far you can ethically take a shot. If I shot a single 3 shot group from a bench and it measured 1" at 100 yards it certainly tells me nothing about what I can and can't do in the field with that same setup. If anything hunting requires stricter test requirements to stay ethical. Paper won't limp away and die a slow painful death if you misjudged your abilities with the rifle in hand.
shotgunjoel
Member
Why stop there, lets do 200 shot groups!
well... benzy.. shoot 30 rounds at 25 yard incriments just to make sure you are positive of where the bullet is impacting at those ranges (and where you can but a full 30 rounds at those ranges, I am sure you will also wait a good 90 seconds between shots to ensure cold bore shots as in hunting..) so that would be 90x30=2700 seconds per 25 yard incriment. You will want to go to at least 150 yards for a likely hunting shot depending on your location... 150/25=6 incriments of shooting. 6x2700=16200 seconds/60 (seconds/min)=270 min/60 (min/hour)= 4 and a half hours (5 hours if you cleaned your gun as necessary) that you spent at a range session making sure your gun shoots where you want it to consistently. Not to mention 30x6=180 shots that were taken in this range session... assuming you are using the ammunition you were planning on hunting with (as different ammunition will impact differently) that is a lot of time and a hell of a lot of money spent on a range session when you could have accomplished just as much takeing 3 3 shot groups at 50,100, and 150 yards AFTER ZEROING to judge bullet rise and fall.
If I can shoot say 3 3 shot groups at 100 yards and keep them under an inch and replicate that at 50 and 150 yards knowing my impacts are within 2 inches of my initial zero, I have great confidence in the gun and my ability to shoot that gun (for hunting applications)... try to flip your coin and get even 5 heads in a row... and good luck...
I am curious how many 30 shot groups you have shot in which the first 5 rounds were perfectly where you wanted them and then the fliers started... assuming you were taking the appropriate time between shots to prevent barrel overheating.
If I can shoot say 3 3 shot groups at 100 yards and keep them under an inch and replicate that at 50 and 150 yards knowing my impacts are within 2 inches of my initial zero, I have great confidence in the gun and my ability to shoot that gun (for hunting applications)... try to flip your coin and get even 5 heads in a row... and good luck...
I am curious how many 30 shot groups you have shot in which the first 5 rounds were perfectly where you wanted them and then the fliers started... assuming you were taking the appropriate time between shots to prevent barrel overheating.
Lets not shoot any and assume the rifle is perfect! A minimum sample of 30 is what the stats department likes to know a study is significant. You can get as sarcastic out of control with it as you like.
I typically do spend 4 hours a range session if not more. I have a few rifles setup as well as targets for each one. I'll cycle them through shot to shot or group to group one rifle to the next allowing the previous to cool or to clean. Unfortunately I don't hunt all that often and when I do its with a .22 at ranges no more than 30 or 40 yards. I know where that bullet will hit and the shots I do take I rarely miss. I may not come back with as much game as others but I am certain of my shot before I take it.
I clearly stated I don't follow the 30 shot rule on most instances. That said before I claim to know how well a rifle will shoot I have shot more than a single 3 shot group or even a couple 3 shot groups. To really know what I and the rifle are capable of I will shoot a 30 round group with the best load I have found. There are many rifles I have shot that would put three consecutive shots into a itty bitty group yet on even a 5 or 10 shot total things got a bit less impressive. And as for your numbers its good to see you need to test at 0 yards to know where that bullet will be. I have never had an instance where I was close enough to touch what I'm shooting.
The point about hunting was that I see a lot of people take out their slug gun (since centerfire rifle with deer is illegal here) shoot 3 shots off a rest and call it good enough to hunt with. Their entire sighting session is over in 1 minute. They don't account for the fact they may be shooting offhand, they don't take in to account any distance variance. They don't take anything into account other than at 75 yards they could hit a paper plate from a bench. As I said I don't always follow what is statistically significant but I certainly am not a 3 shot guy who is happy to put something else in the line of fire after only 3 shots of testing.
If you can put 3 shots in 1" with a hunting load shooting from the same position as you would in the field and feel comfortable shooting to whatever distance go for it. I'm not stopping you. I still feel many hunters today take a couple quick weak range sessions and assume that's how they will shoot in the field. That is what my point was. I have seen a lot of wounded deer. While I'm not a big deer hunter many of my friends are and I tend to at least see the seasons kill before it gets butchered. I would say a good 1/4 had more than one hole shot in them, not always fresh and sometimes from a bow. I think that number is way too high. I blame most of it on hunters who don't know their rifle and ammo and who only practice off a rest, never the way they shoot in the field. Tell me I spend too much time at the range but I have seen what I believe a lot of 3 round groups have done to over inflate a hunters confidence on what shots he can or can't take.
http://www.ar15.com/forums/topic.html?b=3&f=118&t=279218&page=1 This link is a good read on group size. Read the first two posts and also on page 10. It points out what I was getting at. For those who claim 1/4 MOA accuracy all day long I would love to see how all of their targets reflected each other and not just that 3 shot string. Hunting conditions become largely a function of how well shooter can shoot and not how well a rifle can shoot. I think it is of even more importance that a hunter know how they will shoot in the field rather than how their rifle can put 3 shots from a bench.
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the problem I have with hunters is they go out and shoot one shot.. if it hits hear the bulls eye.. they call it good enough.. or similar to your shooting a plate example.. I agree that that is not sufficient in the least.
as to my numbers... count the following... 25, 50, 75, 100, 125, 150...looks like 6 distances to me... at 0 yards you would be shooting at 7 distances.
as to the time you spend at the range.. there is no such thing as too much time spent shooting.. however, most do not have a spare 5 hours to spend at the range at every session.
I see little justification for hunters who must take more than one shot.. I think most of these shot too early or at somthing they couldnt even see (in addition to not properly sighting in their rifle/shotgun to begin with.
to the OP... OUTSIDE TO OUTSIDE of the FARTHEST two shots minus the diameter of the bullet... the more precise the measurement the better.
as to my numbers... count the following... 25, 50, 75, 100, 125, 150...looks like 6 distances to me... at 0 yards you would be shooting at 7 distances.
as to the time you spend at the range.. there is no such thing as too much time spent shooting.. however, most do not have a spare 5 hours to spend at the range at every session.
I see little justification for hunters who must take more than one shot.. I think most of these shot too early or at somthing they couldnt even see (in addition to not properly sighting in their rifle/shotgun to begin with.
to the OP... OUTSIDE TO OUTSIDE of the FARTHEST two shots minus the diameter of the bullet... the more precise the measurement the better.
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