Which load is the most accurate?
- Thread starter Bart B.
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I bet you're going to say "A". And if forced to pick only one I'd agree. But I'd really prefer to see what the median group size was rather than the mean. A single good group can be a fluke, a single poor group can be shooter error. If the median group size were 5" I could be happy with either group.
loose noose
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Depends on what you plan on using the loads for.
A 3 shot group tests the load, 5 shot groups test the rifle, 10 shot groups test the shooter. I can't claim to have come up with that. But I've always felt that way, someone else just put it into words better than I ever did. It comes down to whether you are testing the load, the rifle or the shooter. Thirty shots is 30 shots. I think that a series of groups it doesn't matter if it is 3, 5 or 10, especially fired over several range trips tells more than a single group no matter how many shots fired.
Use your own definition. There's no standard all firearm shooters adhere to.
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On any given day lots of things can happen. Firing 10 groups of 3 shots or 3 groups of 10 shots all on the same day tell me what happened on that day. In your original question you specified 10 groups of 3 shots. I just think the results are more valid if those are done on different days under different lighting and weather conditions. Not to mention a different mind set of the shooter. We all have good days and bad days.
The 10 groups of 3 shots, even done on the same day probably tell enough about the load. Firing them on different days is starting to get into how consistent the rifle is and the skill of the shooter more than the actual load. But at some point the 3 factors have to work together.
The 10 groups of 3 shots, even done on the same day probably tell enough about the load. Firing them on different days is starting to get into how consistent the rifle is and the skill of the shooter more than the actual load. But at some point the 3 factors have to work together.
I didn't specify any time element; groups per day, for example.
Nor were the test conditions, such as the traditional shouldered rifle with it resting on supports on a bench, shouldered in an F class prone position or resting on supports shot free recoil barely touched by the shooter.
'Twas left to the reader to judge from the information presented. Just like 95% of the time in all such stuff is across all media we read.
Nor were the test conditions, such as the traditional shouldered rifle with it resting on supports on a bench, shouldered in an F class prone position or resting on supports shot free recoil barely touched by the shooter.
'Twas left to the reader to judge from the information presented. Just like 95% of the time in all such stuff is across all media we read.
I also liked his "Everything should be as simple as possible, but no simpler." Sorry for the OT.
Russellc
badkarmamib
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And, since we are keeping things simple;
Accuracy is how close to center of target. Both loads are equally accurate, based on average.
Precision is repeatability. The first load is more consistent.
Accuracy is how close to center of target. Both loads are equally accurate, based on average.
Precision is repeatability. The first load is more consistent.
Most often, we ask or state how "accurate" our stuff is meaning the size of the groups it shoots. No reference to how far the bullet holes were to our aiming point. The ratio of asking about "precise" to "accurate" is about 1 : (very big number).
Llama Bob
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First off, I would want to know if the weighted centers of all the groups fell withing the other two groups for that same load. If not, I would add the other two centers to each group as phantom shots (hypothetical zero points) and re-evaluate.
That said I would be fairly certain something's jacked up with load B or the testing. A 9:1 ratio between largest and smallest group for a small number of 10 round groups suggests that the distribution of distance to aim point is modal rather than smooth. In other words, sometimes one thing happens, sometimes another rather than the usual small summation of errors that makes up rifle accuracy. Until that big issue was identified, I'd stick with load A for any practical purpose. There's less I don't understand and most things that need doing can be done with a 2 1/3 MOA rifle.
That said I would be fairly certain something's jacked up with load B or the testing. A 9:1 ratio between largest and smallest group for a small number of 10 round groups suggests that the distribution of distance to aim point is modal rather than smooth. In other words, sometimes one thing happens, sometimes another rather than the usual small summation of errors that makes up rifle accuracy. Until that big issue was identified, I'd stick with load A for any practical purpose. There's less I don't understand and most things that need doing can be done with a 2 1/3 MOA rifle.
Llama Bob
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It would be very nice if "precise" and "accurate" were better defined terms. The meaning seems to flip flop depending on who you're talking with.
For practical purposes, for a figure of merit for a rifle/load I care about the distribution of distances from point of aim in calm air (I'll handle wind). I think that's what you're calling precision?
Based on the given information I would say that A is the best group. If the "average" is 5" for both groups then in the A group the smallest or largest deviation from "average" is only 2". Whereas in the B group the smallest and largest deviation is 4" either way from average. So, if I was going hunting the next day with only these two groupings to consider, I'd chose A.
ironworkerwill
Member
A is the most accurate
B is most precise
B is most precise
I think jmr40 nailed it. We need to see the entire data set, not just the median and the outliers to formulate a meaningful response.
While the overall spread of "A" is lower and thus presumably more "accurate" (depending on how that term is defined) as the mean is the same for both samples, that could be misleading. Say, for example:
The sample for "A" was composed of:
If "accuracy" means getting the greatest number of shots where the point of impact is congruous with the point of aim, then getting groups to a consistently small size would be the objective as the sights can then be adjusted to bring the point of impact to coincide with the point of aim.
While the overall spread of "A" is lower and thus presumably more "accurate" (depending on how that term is defined) as the mean is the same for both samples, that could be misleading. Say, for example:
The sample for "A" was composed of:
- 3.0 inches
- 6.9 inches
- 3.2 inches
- 6.7 inches
- 3.5 inches
- 6.6 inches
- 6.8 inches
- 7.0 inches
- 3.4 inches
- 3.1 inches
- 5.0 inches
- 5.0 inches
- 5.0 inches
- 1.0 inches
- 5.0 inches
- 5.0 inches
- 5.0 inches
- 5.0 inches
- 9.0 inches
- 5.0 inches
If "accuracy" means getting the greatest number of shots where the point of impact is congruous with the point of aim, then getting groups to a consistently small size would be the objective as the sights can then be adjusted to bring the point of impact to coincide with the point of aim.
Nature Boy
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So that means Einstein was OK with throwing out the flyers.
Sunray
Member
"...Accuracy is how close to center of target..." Nope. Accuracy is about consistent groups. Where it hits before sighting in makes no difference.
Since the loads are not consistent, neither of those are exactly accurate. Good enough for deer though.
'B' would be out of the 10 ring on an NRA 300 yard rapid fire target. And on an NRA No. MR-63. Out of the 9 ring with that largest group. Well out of the 10 ring on the 200 yard SR target.
Since the loads are not consistent, neither of those are exactly accurate. Good enough for deer though.
'B' would be out of the 10 ring on an NRA 300 yard rapid fire target. And on an NRA No. MR-63. Out of the 9 ring with that largest group. Well out of the 10 ring on the 200 yard SR target.
That's correct if we assume that the centers of all six groups are in the center of the 10 ring or the average distance to center for loads A and B is the same. Regardless of accuracy, load A is more precise than load B given the small data set.
No .. that's called precision.
That's like saying the earth could be flat or round depending on who you're talking with, but only one is true. There's no confusion over the definition of the terms accuracy and precision. These terms have been defined and understood for centuries in the scientific community. The problem in the shooting community is that most shooters don't achieve accuracy and precision when they shoot and they substitute precision for accuracy. Shooting small groups is easier than shooting small groups while also hitting what you're aiming at. Put up a target with five 1" dots and then shoot one round at each dot at 100 yards or 2" dots at 200 yards. Forget group size and see if you can put a hole in each dot. It's harder than it sounds, even for those that commonly shoot 5-shot sub moa groups.
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