Legit 1" groups

[cal30_sniper]

I think what I'll do is add another snippet of code that calculates a random angle and distance that the rifle throws the shot from the shooters point of aim. The arcsine of that angle and the distance from POA will give the actual radial distance from the bullseye. I'll post results when I have them.

 

[Trent]

Cal30 -

There's two distribution groups I've noticed with shooting. One tends to place the majority of rounds closer to the center with less frequent outliers. (That's the norm). The second type presents as more of a ring with a heavier distribution OUT of a lighter populated inner circle (damaged crowns and most Klashnikovs fall under that type)

Also, group distribution patterns are rarely circular, but often that's the shooter having a slightly misaligned rifle (canted scope), velocity deviation from an inconsistent load, etc. There's usually (not always) a cause that can be found for oval shaped or "tilted" groups.

 

[Tempest 455]

Yes, with good equipment you can have legit sub 1" 5 round or 10 round groups. Here is my son shooting a 5 round group .865" with a .22 at 13. No bench rest, front bipod and rear bag. He's done similar with 1" for 10 rounds at 100 with this gun.

He just shot his 1st 1,000 yard F class match 2 weeks ago at 14. Dad was proud!

 

[Nwflycaster]

Every rifle and shooter is different. For me, a 1" group means that I'm in desperate need of a new barrel. My 6mm ppc groups at 0.15 on average with its best being a 5 shot group at 0.054". I have an as yet unfired 6mm br but I won't be happy with any load until it is under 1/4". My AR-15 match rifle will keep groups under 1/2" and even my Tikka .338 will hold sub 1" groups but it will beat you up if you shoot it much. I'd have to say I don't expect this kind of accurace out of anything else I own though under calm conditions my Anschutz 1413 Super Match would consistently do it also.

 

[corncob]

Cal30, would you add a 4-moa rifle curve next time you post one of those charts? I can't shoot that well (10 moa from standing unsupported is what we are working with here, not 3 (who are you people?) and would like to know just how crappy of equipment I can practice with and still trust that the poor, but improving, groups reflect the shooter's ability, not the rifle/ammo.

 

[PPS43]

3-shot groups aren't very good for accurately judging a rifles accuracy

I did a numeric simulation to see how big the difference is. Turns out it's not as big as I expected:

3 shot group size: mean=2.401, stdev=0.879, cv=0.37
5 shot group size: group mean=3.070, stdev=0.828, cv=0.27
10 shot group size: mean=3.813, stdev=0.738, cv=0.19

 

[jbkebert]

Earlier I had ask about the length of time one takes between shots. My newest rifle is a old one. A Springfield 1903 Mark 1 that has been sporterized. From a cold bore at 100 yards I can fire the first two shots in fairly quick succession. The bullets generally touch. But the third and fourth shots start to open up with the thin barrel heating. Even waiting approx 1 to 1 1/2 minutes between shots the results are the same. Either way I am not complaining about the accuracy of this rifle. Heck the action and barrel are 96 years old with a 60 year old fixed 4x scope.

 

[jbkebert]

I can't figure out how to post pic's from a previous attachment. So here is a link to the thread.

http://www.thehighroad.org/showthread.php?t=695463

 

[Andrew Leigh]

Was reading an interesting article on group sizes.

http://www.the-long-family.com/group_size_analysis.htm

 

[jmr40]

3-shot groups aren't very good for accurately judging a rifles accuracy

A single 3 shot group or 5 shot or even a single 10 shot groups does not mean much, but a series of 3 shot groups fired over a long period of time tell you all you need to know about a hunting rifle.

If you shoot in some sort of competition where 5 or 10 shot rapid fire groups mean something then fine.

This is a single 3 shot group. Did I get lucky? You bet I did. But I don't go around telling people I can shoot .1" groups all day long. I do feel pretty accurate when I say I have several rifles that are consistent 1/2"-1" MOA guns. And that I'm capable of shooting 1/2 MOA if the rifle is up to it. These are all shot a padded rest under the forend of the rifle. No lead sleds, or other rests.



But these groups are not luck. This is pretty normal,xcept for the one Kimber group. These were shot from a variety of guns on several different range trips over a period of several years.


And some groups at 200 yards

 

[Kachok]

Seems to be alot of judgement on this forum and others about what groups count as Sub-MOA if you shoot three groups of three people act like it should not count until you are shooting five shot groups, and when you do shoot five shot groups they tell you you it does not count until you do ten. Sorry but I am not shooting five ten shot groups to satisfy anyone's issues. If I can keep it in the touching holes or awful close to it over three of four groups I am quite certain that will give me more then enough accuracy for the hunting I do and if it stays under an inch it is sub-moa to me, and I am not really worried about someone calling unfair because I shot it from a stable rest or that I did not test it at 600 yards in a crosswind, when I am doing load development I want every advantage I can possibly use to evaluate the true accuracy of the rifle/load at 100yards, so someone crying over me using a sand bag is total nonsense, I would wager that nobody here could keep consistent sub-MOA groups free standing at 100yards. There is my rant for the day, oh that's right I already had my rant on that muzzlebrake thread

 

[Art Eatman]

The accepted accuracy standard for some sixty-plus years that I know of has been the five-shot group. I guess that came from the bench rest crowd, or maybe even earlier.

However, what counts, seems to me, is the regularity and reliability of getting your acceptable group size, whether MOA or whatever. I've had five rifles through the years which (once they were set up and loads developed) ALWAYS beat one MOA for five shots. (Realize of course that everybody has a day when they couldn't hit a bull in the butt with a bass fiddle--but that's not the rifle's fault.)

However, once that reliability was established, three-shot groups provided all the useful information I wanted for a hunting load. Target, IMO, is a different deal entirely.

 

[bushmaster1313]

Seeing is believing:
My .257 Roberts with Nosler factory ammo:

Shoots 100 yard groups like this:

Other ammo shoots larger groups (2" to 3")

 

[cal30_sniper]

Not to call anyone out here, but like I said earlier, when a rifle and shooter have done it several times in a row, that's when I start to sit up and take notice. I've seen a whole lot of rifles that people claim are MOA, but you rarely see more than one group on a target. There's not a rifle in my safe that doesn't shoot a sub-MOA 3 shot group every now and then. However, in my experience, there are very few hunting rifles that will do it consistently. I've seen proportionally a lot more pictures of guns that shoot "sub-MOA" than I've ever owned, and I've gone through a lot of hunting rifles with a lot of different loads. I've started taking it all with a big grain of salt unless I see strings of shots as examples. Reading on here, you'd think everybody has a rack full of rifles that shoot sub-MOA with factory ammo, but the only ones I ever see actually doing this at the range are the benchrest crowd. I don't remember the last time I saw somebody shoot sub-MOA groups at the range with a sporting rifle. When I shoot some, it seems like half the range is over there going gaga about my rifle by the time its over. Something about that just doesn't add up.


For me, seeing is believing. Like I said earlier, 5 groups of 5 shots, with a mean and median that is 1.00" or better. Statistically and realistically, there's a big difference between 3 and 5 shots. There's also the repeatability that eliminates the "fluke" group that so many people use to brag about the accuracy of their rifle. I've got one hunting rifle that can do that, and two others that are very very close. It's a hard standard, but an honest one, that I feel really separates a truly accurate rifle from a good or run of the mill rifle. Is it necessary for hunting? Absolutely not. Does it make a statement about the accuracy of a rifle? You betcha.

1909 Peruvian Mauser in 7x57 AI. Five 5-shot groups, 5 different loads, 0.97" average group size, 1.00" Median group size. That's with crimped hunting bullets seated at the groove so they will feed and function with 100% reliability in the hunting environment the rifle was designed for. That's a MOA rifle, right on the money. Keep in mind that immediately before I shot this target, I fired 3, 3-shot groups on another target. They averaged 0.66". That's the difference between a 3 and 5 shot group.

EDIT: These groups were fired off a front rest that consisted of a 4x4 topped with a shot bag full of sand. I don't own anything more sophisticated for a rest, and I most likely never will. That takes all the fun out of it.

 

[Andrew Leigh]

Good post Cal30 Sniper,

in my earlier post I included a link which refers to some statistical studies. This link intimates that for every shot, on average your group will open up. Their studies give a multiplication factor to allow the user to relate the larger group sizes to "real" MOA accuracy by applying a multiplication factor.

Taking their table with the multiplying factors into account then in your case;
3 shot groups were 0.66" X 1.158 = 0.75MOA
5 shot groups were 0.97" X 0.876 = 0.85MOA (using differing loads mind)
Either way you and you rifle are consistently well within MOA accuracy.

Also interesting was the fact that their statistical analysis would indicate that a 4 shot group is more reflective of the accuracy of the rifle.

On the side Cal30 you were a little unfair on yourself shooting different loads on the 5 shots groups. Had you shot your accuracy load then those groups would be tighter. In my experinence, loads not on the accuracy node will print differently (not talking height etc. but rather pattern) this makes interpreting the groups difficult and one cannot see what is going wrong with technique.

Nice shooting though.

 

[ford8nr]

Cal30, You and I are on the same thought process, hense the title of the thread. Listening to people at the club I belong to and seeing whats shot on the targets I just don't see many people 'shooting' 1MOA groups. Maybe one day years past they clamped the rifle down and the gun shot 1MOA. Up to fairly recent times 1MOA for a GUN was the bench mark. Now I believe there are a fair number of production guns that a capable of 1MOA with the right load. Most people won't spend the time looking for the right load, factory or handloaded. And from what I've personally seen on the range, the average shooter is incapable of consistantly shooting MOA.

 

[cal30_sniper]

Andrew, I'm sure I could do better with a hand selected load, and I will on my next round of workups. Personally, when I get around the 1MOA range like this, the velocity and reliability of the load becomes more important to me than squeezing the last bit of accuracy out.

Of course, a lot of people would cut out the 51gr group, call the outlier a flier, and say that the rifle shoots 1/2MOA 4-shot groups all day, haha.

 

[Pete D.]

comparisons

3 shot groups were 0.66" X 1.158 = 0.75MOA
5 shot groups were 0.97" X 0.876 = 0.85MOA

Just to add an idea about group size. The measurements above are linear c-to-c numbers, essentially one dimensional.
Groups, though, are two dimensional and cover or contain an area.
Let's say that the two groups above were circular or roughly so....a circle with a diameter of 0.66" has an area of 0.342 sq.in. The second group, measured the same way, is more than twice the size....a circle with a diameter of 0.97" has an area of 0.738 sq.in. More than a 200% increase in size.
If you use a target with a a grid of one inch squares and want to use that criteria, the difference is slightly greater (0.9409sq.in vs. 0.4356 sq.in)
Pete

 

[Nwflycaster]

Hangingrock (post# 44), to answer your question my last 10 targets on the SR target shooting 200 yards unsupported offhand are:
2 x 100
4 x 99
3 x 98
1 x 97

These were shot using my Les Baer NRA Match AR-15 with iron sights (Warner no1 rear and Centra front) and wearing my leather shooting jacket. The ammo was factory match Federal Gold Medal 77 grain.


The general public average shooter always has me shaking my head. How some people can shoot from a rest and litterally spray shots all over the paper, and probably several off of it looking at their targets just baffles me. You would really have to work hard at it to shoot that poorly, I just don't get it.

 

[Andrew Leigh]

Nwflycaster,

I am a hunter so my comments are from that perspective.

I suppose that would be due to "fitness of purpose", given the size of the "kill zone" that presents on a deer many consider 1MOA to be more than satisfactory to ethically hunt and kill. That would have dead deer out at 300yds. Some would even argue for a higher MOA value.

Many hunters only shoot in season so the rifle comes out a couple of times a year, practice is often limited to ensuring the zero is where you want it and to allow the recoil to remove the cobwebs.

Converse to your opinion, I believe that you don't have to work hard to shoot poorly, you have to work hard to shoot well. I take myself as an example, I was saying to a friend that I never practice, the only practice I get is when developing loads. Both rifles are capable of 0.75MOA and better if I take the time to concentrate a little. This year I have determined to practice and to shoot the same load over and over again, my new goal is MOA @ 200m. This is not going to kill the buck any quicker but I believe in the ethical kill so if I want to go for the brain or the heart at 200m I want this freedom and not be limited to the engine room due due lesser skill.

From an equipment perspective many hunters have budget rifles which deliver budget performance most of these rifles never get tweaked. They have no bedding, poor triggers, shoot off the shelf standard ammo rather than match or handloaded ammo. So one can see what some would be elated with results that fall short of a competition shooter.

Hunters have other stuff to worry about. Creeping up to the animal and then controlling the rasping heavy breathing from the exertion. Shooting from often impossible positions, remaining concealed, controlling adrenaline, estimating range and bullet drop, estimating bullet point of entry so that the vitals are pierced, evaluating if the shot is doable etc. This for us is where it really matters, these are our 10X.

Does that make any sense?

 

[PPS43]

Their studies give a multiplication factor to allow the user to relate the larger group sizes to "real" MOA accuracy by applying a multiplication factor.

The "real" MOA in that article is not group size, but standard deviation (assuming normal distribution).

It is a perfectly good metric, but calling it MOA is confusing because MOA usually refers to group size.

 

[Andrew Leigh]

"Notice that if you use three shot groups to determine the actual accuracy, you will observe a 0.863” average group size for a one MOA rifle. In other words, you must measure the average group size in inches, and multiply by the correction factors in Table 1 to get the actual MOA accuracy for the rifle. Remember that this example assumes a 100 yard target range. For ranges other than 100 yards, one can scale the value obtained from the group size measurements after correction by the factors in Table 1 by the ratio of the actual range to a standard 100 yard range. A fairly accurate way to do this measurement without calculation is to use 4 shot groups, as the correction factor is closest to one (0.979)."

The above is a quote from the article, what am I missing?

 

[PPS43]

The above is a quote from the article, what am I missing?

I was referring to this part:

"A Matlab program was written that simulated 100000 shots from a rifle, with a one MOA double sided standard deviation of cone angle, at a target 100 yards away."

and later

"we have simulated the perfect one MOA rifle".

 

[Nwflycaster]

Andrew,

I am also a hunter not only a competative shooter. I'm well aware of what hunters go through during a hunt, I've been doing it for 40 years. The thousands of hours I have spent with a rifle in my hands does give me a huge leg up on your average hunter when it comes the the shooting aspect, but during the stock I am on the same level as everyone else and probably worse off since I don't get to spend extra time in the woods doing some pre planning. But I am prepared for the shot whatever it may be, taped to the stock of my hunting rifles is a card with that rifles ballistics that I can look at if I have the time that will give the bullet drop out to 500 yards in 50 yard increments. I have only ever used it once, but it's there. The longest shot I have ever taken at an elk or deer has been under 250 yards, though I have shot two antelope at over 700, that's when the cards came in handy.

When I say you have to work at it to shoot as bad as I see sometimes, I don't mean litterally they are trying to shoot bad. It just takes very very little effort to not shoot a two foot group from a rest at 100 yards. Case in point, I took my daughter with me to the range last summer for her first time and set her up with one of my .22 cal rifles with a scope on it. She shot three boxes of ammo at 100 yards, so 150 rounds and her group was under five inches for all shots fired. I coached her before she started and had her doing some dry firing while I watched what she did. Gave her a few tips then just watched as she had some fun. Even she noticed when we went down range and mentioned how so many targets were just two square feet of paper with holes all over the place.

You said yourself that you never practice, just make sure you are sighted in before hunting season. Thats fine, I wish all hunters would do at least that much. You also said your rifle is capable of .75 MOA, thats great for a hunting rifle. Even though you don't practice, from what you wrote I'll bet you're not one of the people I'm talking about that cannot keep their shots on a 2' x 2' peice of paper from 100 yards using a rest. You said you develop your own loads so you must understand where I am coming from, if you can't shoot any kind of group you can't work up a load, you wouldn't know what is good or bad.

 

[Andrew Leigh]

@PPS43 - I am not a statistician so will have to accept what you say though that is not how I understood it.

@Nwflycaster - So we are actually on the same page, paragraph, sentence and phrase!