In your mind what is the difference in reloading for repeatability or for accuracy?
Looking for thought out opinions and discussions. roger

I have a strong opinion that for a hunting rifle repeatability is much more important than a little gain in accuracy. I've shot some loads that were accurate at warm temperatures but inaccurate in cold temperatures. For example an old .22 Hornet was a 1.0 MOA rifle at 80 deg F but a 2.0 MOA rifle (or worse) at 20 deg F. My usual way of working up a load now is to start a few grains less than maximum with a given powder and bullet and work it up to past maximum velocity a grain at a time for a large case. While doing this I am also shooting a target for accurracy. I figure if a small group is produced even with a large variation in powder charge, pressure and velocity, the bullet/powder combination is fairly insensitive to temperature which would also vary pressure and velocity. Loads worked up this way seem to shoot well for me no matter what the temperature is. I've read numerous times where a bullet/powder combination gives very small groups at a paticular charge level, but groups get much larger if the charge level is changed either higher or lower. I would guess that if temperature would be different than the temperature the load was worked up at, accuracy would also suffer.

Roger ; I reload for the repeatability of ACCURACY !. After all Repeatability is accuracy and not just a fluke !.

It's why I personally load #16 , one fouler and #3 groups of #5 for score and the total C too C measurement of each group is my figure .

A #3 shot group is OK for Hunting rifles ,as 98.8% of the time no one shoots more than that while hunting . Match ,Target or Bench rest is a
different animal and requires precision accuracy ; which is repeatability !.

quote:

Originally posted by Doc224/375:
Roger ; I reload for the repeatability of ACCURACY !.

+1

How many here think that rounds that fire the bullet down the bore equals "successful handloading" regardless of accuracy?

Actually, we often misuse the terms. Accuracy and repeatability (consistancy) are quite different things.

Repeatability is groups. No firearm can be accurate unless it's repeatable.

Accuracy is the ability to hit what you want; inaccuracy is correctable with sight adjustments.

quote:

Originally posted by Jim C. <><:
Actually, we often misuse the terms. Accuracy and repeatability (consistancy) are quite different things.

Repeatability is groups. No firearm can be accurate unless it's repeatable.

Accuracy is the ability to hit what you want; inaccuracy is correctable with sight adjustments.

So far the best analogy.

I agree too that repeatability is consistency which is hitting the same spot every time you pull the trigger. Accuracy is the shooters ability to use that consistency to place the shot. You have consistent rifles and accurate shooters.

Actually, what you are looking for in a rifle is both accuracy and repeatability, aka precision.

For example:

Poor precision - hits widely scattered
Poor accuracy - hits far off center


Poor precision - no gross errors, but hits widely scattered
Good accuracy - on average, hits are evenly distributed around center


Good precision - all hits are close together
Poor accuracy - although all hits are close together, the center is still missed.


Good precision - all hits are close together
Good accuracy - all hits are near the center

I don't very often shoot a 5 shot group. My rifles are for the most part hunting rifles. I want the first 2 maybe 3 rounds to hit the same point on the target with a cold barrel each and every time. If shots 4&5 open it up to 2" I could care less as long as the first 2 are touching.

quote:

Originally posted by Jim C. <><:
Actually, we often misuse the terms. Accuracy and repeatability (consistancy) are quite different things.

Repeatability is groups. No firearm can be accurate unless it's repeatable.

Accuracy is the ability to hit what you want; inaccuracy is correctable with sight adjustments.

I can readily accept what you say as gospel except an accurate rifle has to be repeatable ( degree). Let's consider first shot cold clean barrel vs. dirty barrel for a start. roger

Anyone can blunder into a 3 shot cloverleaf or a one-hole group from time to time. What does the gun do in multiple shooting sessions? Can it do it throughout the year? Repeatability is the mark of accuracy. Just because a rifle can make a cloverleaf from time to time doesn’t make it a target rifle.

Sounds to me like another "how many angels can dance on the head of a pin" discussion. That'll probably go for several pages while everyone parses around splitting hairs about the difference between accuracy and repeatablity.

To say that a rifle that doesn't hit what you want is inaccurate but if you adjust the sights, it becomes accurate doesn't make sense to me. The bullets went to where the rifle was set up for it to go and if you have ammo that is highly consistant, it will continue to send the bullets to the same point. The fact that the group isn't where you want it is inmaterial.

quote:

Sounds to me like another "how many angels can dance on the head of a pin" discussion. That'll probably go for several pages while everyone parses around splitting hairs about the difference between accuracy and repeatablity.

To say that a rifle that doesn't hit what you want is inaccurate but if you adjust the sights, it becomes accurate doesn't make sense to me. The bullets went to where the rifle was set up for it to go and if you have ammo that is highly consistant, it will continue to send the bullets to the same point. The fact that the group isn't where you want it is inmaterial.

I agree almost 100%. However I did have a rifle that even after adjsuting the sights the next time out it would be off. Even after bedding, new scope etc it would still very from time to time. I finally cured it. I used it's guts for another project.

A one minute group once a year is not a one minute gun. It's the blind squirrel finding a nut.

quote:

Originally posted by wasbeeman:
Sounds to me like another "how many angels can dance on the head of a pin" discussion. That'll probably go for several pages while everyone parses around splitting hairs about the difference between accuracy and repeatablity.

Beeman your opinion is well understood and it is exactly why this thread was started.
The hunter in the field sights in on his game and fires from a cold barrel at a fair distance and drops his game on the spot. It is hard to see where repeatability comes into play but the combo of hunter, equipment and his familiarity of performance of that ammo and rifle do play the major role in accuracy. A single shot has nothing at that time to do with repeatability. Now that is my humble opinion after cleaning off that pin head. roger

If the question is "what would be more preferable, a rifle that puts it's first shot from a cold clean bore to the same POI everytime but groups at 1.5 MOA or a rifle that needs fouling shots etc. but groups to .25 MOA?"

My answer would be the former for a big game rifle.

If you cut an inch off of a yard stick. It will
measure with repeatability but not be accurate.
These are specific terms with specific meanings.
Good luck!

Nice post GrayBird!

quote:

Originally posted by Hot Core:
Nice post GrayBird!

X2 roger

quote:

Roger ; I reload for the repeatability of ACCURACY

Another +1

I also appreciated the posts by Ghubert and Graybird.

When I go to the range, I'm always very careful with my first shot out of a cold barrel. I want to see if its where it was when I last shot. In hunting situations, that's the one that counts. If the rifle shoots 1/2 inch groups but you can't really depend on the first shot out of a cold barrel, your not going to have much confidence when hunting.

Another thought: What do a lot of people do to their rifles before opening day of season? They clean in--swab the barrel, etc. Some guns shoot differently after a few fouling shots, but the guy who has cleaned his gun before season, often doesn't know what the rifle will do on that first shot out of a cold & clean barrel.

My preference here is to clean my gun before season opens, but then go to the range and shoot a few shots through it--double checking scope settings, etc. I then, hunt with the gun in this condition--not cleaning it again before season.

Okay, on GB's third target, the rifle was precise but not accurate. When you move the sights to move the group into the bull, then the rifle becomes precise and accurate??
Still sounds like a play on words but I'll sit over here in the corner and be quiet and hopefully learn something.

wasbeeman,

You're correct.

The accuracy versus precision - target analogy is commonly used in many scientific fields to describe instrument dependability, etc. In our case, our instrument being tested is the rifle, bullet, powder, etc. combo for precision. When it comes to accuracy, we have the ability to adjust the precision location to also become accurate, so that, all of the bullets hit within the bulls-eye.

We often use the terms accurate very fluidly when talking about rifles. We are actually talking about precision as outlined in the above targets. As outlined in target #2 you can have an accurate rifle that sprays 10 shots all over the target with the average of those 10 shots being very near the center of the target. In the rifle world, we would say this load combo, etc, is not accurate when it acutally is comparitively speaking to the normality of the data (bullet hits).

What we are all actually striving for is precision, or as bartsche stated in his original post repeatability. The bullets hit in the same location every time the trigger is pulled. We have the ability to adjust the precision location of the rifle to make it more accurate by adjusting the scope.

+ another for graybird's post/answer on differentiating between the two. The terms are intermingled by most of us though. Many believe that "accuracy" is the ability of the firearm/ammuntion to group closely and "precision" is the zeroing of the firearm and sit's sights so that group hits a specific place at a specific distance. In other words; the accuracy of a firearm/ammuntion can allow you to hit a target with precision.

Not disagreeing, just stating how the perception is different.

Larry Gibson

quote:

The fact that the group isn't where you want it is inmaterial.

That suggests sight adjustments are immaterial and I don't think you believe that. ??

The sights are immaterial from the standpoint that the rifle that shoots small groups can be corrected if the sights are adjusted (Graybeard's 3rd example) while one that shoots a shotgun pattern (but on target) can't be fixed.

Take it another way and remove the sights from two guns that are identical save the fact that one shoots a repeatable, 1" group off the target in the same spot off target (when fixed in a solid rest), while the other shoots an 8" group on the target under the same conditions. We can correct the 1" group onto the target, but can't necessarily make the 8" group smaller if we want everything else kept the same. As others have already noted the shooting world uses the word accuracy to interchangeably and incorrectly mean what scientists define as two separate entities: precision and accuracy.

quote:

Match ,Target or Bench rest is a
different animal and requires precision accuracy ; which is repeatability !.

The ultimate accuracy would be having the firearm able to drop every single shot into it's own diameter of entrance hole !.

As I simply have NEVER SEEN ANY FIREARM DO THAT !. So the next best thing is REPEATABILITY .

Most of us don't sight for POA impact ( I don't any way I shouldn't speak for others ) Example most hunting rifles I own are 1.5-2.75"+
at 100 Meters ,so my point of aim is dead center of target and shots impact at plus elevation center of target hopefully . When they don't with known loads then comes checking and tightening procedures coupled with scope adjustment . If that fails I generally change the scope and reevaluate the situation . If it still fails I become irritated and remember POWDER isn't always the same just because the name and number on the container says it is !. Redo loads check and continue searching for the magic solution again .

PS ; I do gauge my Barrel after the second scope change to eliminate any nonsense like chasing my tail .

At times three of us play a game we call chase the hole! first guy shoots a hole in the target at 50 yds. and the next guy tries to hit it.The third guy tries to hit the second hole and the first the third and so the game continues. There probably are more hits than misses.
Would it be safe to say that the rifles and ammo are repeatable and the shooters are using them with a degree of accuracy? Just a thought. roger

quote:

Originally posted by bartsche:
Would it be safe to say that the rifles and ammo are repeatable and the shooters are using them with a degree of accuracy? ...

If it were my buddies, I'd just say, "They were Flinching them in!"

same meaning to me. An accurate rifle is a consistant rifle and a consistant rifle is an accurate rifle. Im happy when a gun shoots 5 shot groups at an inch or less EVERY time and Never changes poa. If it doesnt do both of these i work till it does or it goes down the road.

quote:

Originally posted by Hot Core:

quote:

Originally posted by bartsche:
Would it be safe to say that the rifles and ammo are repeatable and the shooters are using them with a degree of accuracy? ...

If it were my buddies, I'd just say, "They were Flinching them in!"

Kind of what I said. Consistent guns and accurate shooters.

I think were all splitting hairs at this point.

I expect repeatability of accuracy. The POS (aka Kimber Montana - .270 WSM) that I just shitcanned occasionally would group wonderfully. One time, it put 5 shots literally into 1 ragged hole. I could never repeat that group for the life of me again and I had all of my original load info. I sent that thing down to the Lower-48 twice for work, once for a brand new Lilja barrel. No good!!
I expect confidence in all of my equipment and if a rifle can't be counted on to put the shot where I want, I don't use it. Repeatability invokes confidence that when push comes to shove, if you screw up, it's you & not the rifle.
BTW, the new .270 WSM I have appears that it will be a real keeper and I'm looking forward to taking it sheep hunting next Aug.
Bear in Fairbanks

But we're not scientist. We're shooters and hunters and reloaders for the most part. As I said earlier, it's fine and dandy for scientist to debate at length those angels and other sophist to define "is" but if my rifle sends the bullets to the same small place and does not wander around from range session to range session, it is accurate even if the group is adjusted outside of the bull. If it does this day in and day out, for weeks and months and years, it is accurate AND repeatable.
Again, I think we are splitting a hair and arguing about the thickness.
I'm gonna lay down and put a cold rag on my poor aching head.

quote:

Originally posted by wasbeeman:
I'm gonna lay down and put a cold rag on my poor aching head.

Try a couple of small doses of Liquid Corn.

Here's what Wiki has to say about the original topic . Accuracy versus precision; the target analogy
High accuracy, but low precision
High precision, but low accuracy

Accuracy is the degree of veracity while in some contexts precision may mean the degree of reproducibility.[citation needed].

The analogy used here to explain the difference between accuracy and precision is the target comparison. In this analogy, repeated measurements are compared to arrows that are shot at a target. Accuracy describes the closeness of arrows to the bullseye at the target center. Arrows that strike closer to the bullseye are considered more accurate. The closer a system's measurements to the accepted value, the more accurate the system is considered to be.

To continue the analogy, if a large number of arrows are shot, precision would be the size of the arrow cluster. (When only one arrow is shot, precision is the size of the cluster one would expect if this were repeated many times under the same conditions.) When all arrows are grouped tightly together, the cluster is considered precise since they all struck close to the same spot, even if not necessarily near the bullseye. The measurements are precise, though not necessarily accurate.

However, it is not possible to reliably achieve accuracy in individual measurements without precision—if the arrows are not grouped close to one another, they cannot all be close to the bullseye. (Their average position might be an accurate estimation of the bullseye, but the individual arrows are inaccurate.) See also circular error probable for application of precision to the science of ballistics.
[edit] Quantifying accuracy and precision

Ideally a measurement device is both accurate and precise, with measurements all close to and tightly clustered around the known value. The accuracy and precision of a measurement process is usually established by repeatedly measuring some traceable reference standard. Such standards are defined in the International System of Units and maintained by national standards organizations such as the National Institute of Standards and Technology.

This also applies when measurements are repeated and averaged. In that case, the term standard error is properly applied: the precision of the average is equal to the known standard deviation of the process divided by the square root of the number of measurements averaged. Further, the central limit theorem shows that the probability distribution of the averaged measurements will be closer to a normal distribution than that of individual measurements.

With regard to accuracy we can distinguish:

* the difference between the mean of the measurements and the reference value, the bias. Establishing and correcting for bias is necessary for calibration.
* the combined effect of that and precision.

A common convention in science and engineering is to express accuracy and/or precision implicitly by means of significant figures. Here, when not explicitly stated, the margin of error is understood to be one-half the value of the last significant place. For instance, a recording of 843.6 m, or 843.0 m, or 800.0 m would imply a margin of 0.05 m (the last significant place is the tenths place), while a recording of 8,436 m would imply a margin of error of 0.5 m (the last significant digits are the units).

A reading of 8,000 m, with trailing zeroes and no decimal point, is ambiguous; the trailing zeroes may or may not be intended as significant figures. To avoid this ambiguity, the number could be represented in scientific notation: 8.0 × 103 m indicates that the first zero is significant (hence a margin of 50 m) while 8.000 × 103 m indicates that all three zeroes are significant, giving a margin of 0.5 m. Similarly, it is possible to use a multiple of the basic measurement unit: 8.0 km is equivalent to 8.0 × 103 m. In fact, it indicates a margin of 0.05 km (50 m). However, reliance on this convention can lead to false precision errors when accepting data from sources that do not obey it.

Looking at this in another way, a value of 8 would mean that the measurement has been made with a precision of 1 (the measuring instrument was able to measure only down to 1s place) whereas a value of 8.0 (though mathematically equal to 8) would mean that the value at the first decimal place was measured and washttps://forums.accuratereloading.com/groupee_common/ver1.3.6.9756/platform_images/blank.gif found to be zero. (The measuring instrument was able to measure the first decimal place.) The second value is more precise. Neither of the measured values may be accurate (the actual value could be 9.5 but measured inaccurately as 8 in both instances). Thus, accuracy can be said to be the 'correctness' of a measurement, while precision could be identified as the ability to resolve smaller differences.

Precision is sometimes stratified into:

* Repeatability — the variation arising when all efforts are made to keep conditions constant by using the same instrument and operator, and repeating during a short time period; and
* Reproducibility — the variation arising using the same measurement process among different instruments and operators, and over longer time periods.


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