AR Sponsor
The Hunting Thread (Page 1 of 3)
Posted: 3/15/2015 11:04:38 PM EDT
[Last Edit: WILSON][Edited]
|
Dedicated to Zhukov for his tireless efforts to improve the signal to noise ratio on this site. The Internet Commando’s Nephew (The scene opens with Billy rushing into his house to tell his mother of his accomplishments while at the shooting range with his uncle that afternoon.) Billy: Guess what, Mom! I can shoot sub-MOA groups all day long with my chrome-lined, NATO chambered AR-15 using XM193 ammunition. I’m a real Internet Commando now! Mother: Billy, how many shots were in those groups? Billy: Aw, gee Mom. They were only 3-shot groups, but all the other kids are shooting 3-shot groups. Mother: And if all the other kids jumped off a bridge, would you do that too? Billy: No, Mom Mother: Billy, you know that 3-shot groups aren’t good for you. What have your father and I told you about 3-shot groups? Billy: 3-shot groups don’t mean jack-shit? Mother: That’s right, Billy. So how many of those 3-shot groups of yours were actually sub-MOA? Billy: Well . . . only two. Mother: And how many groups did you actually fire? Billy: Five. Mother: Billy . . .? Billy: Ok, it was ten groups. You happy now? Mother: So, you fired ten, 3-shot groups and CHERRY-PICKED two groups to brag about? Your father and I raised you better than this, Billy. Billy: Sorry, Mom. Mother: Sorry doesn’t cut it, young man. I’m going to have a long talk with your uncle and you’re no longer allowed to log-on to glock-gab.com. That site is rotting your brain. Billy: But Mom! Mother: No buts, Billy. And the only reason that I haven’t grounded you is because you haven’t used the "F” word. Billy: You mean . . . f . . . l . . . Mother: Watch it, Billy. Billy: Flier! (Billy turns and runs to his bedroom as fast as he can.) Mother: That’s it! You’re grounded, and just wait until your father gets home! This is all because of that uncle of yours!” After Billy finished his week of being grounded, his parents decided to supervise an experiment at the shooting range with him to reinforce the folly of using 3-shot groups to evaluate the accuracy (technically, precision) of a rifle/ammunition combination. Shooting from a bench-rest at a distance of 100 yards using his father’s Krieger barreled, semi-automatic AR-15 (Billy’s actually a pretty good shot for his age) and using his father’s hand-loads topped with Hornady 55 grain FMJ projectiles, they had Billy shoot 30 shots in a row on thirty different targets; one shot per target (all while monitoring the wind conditions on the range using a Wind Probe). (Prior to Billy firing his shots, his father fired a sub-MOA, 10-shot control group from the same rifle using match-grade hand-loads.) They then collected their targets and headed home to continue the experiment. Once at home, they entered each of the thirty targets into the computer using the software program RSI Shootng Lab. Next, they used the software program to form ten, 3-shot groups from the thirty individual shots. (The first 3-shot group was formed from shots 1-3, the second 3-shot group was formed from shots 4-6 and so on.) The results are pictured below. (The point-of-aim for the groups pictured below is the double white circle.)  The ten, 3-shot groups.  Billy’s parents pointed out to him that the 3-shot groups had wide variations in their extreme spreads from shot-group to shot-group. The extreme spread of the largest 3-shot group (group number 8) was five times as large as the smallest 3-shot group (group number 2). They also pointed out that the centers of the various 3-shot groups varied quite a bit in their location as referenced from the point-of-aim. For example, all three shots from group number 3 are higher than the point-of-aim, while all three shots from group number 4 are lower than the point-of-aim. Also, the center of group number 3 is located to the left of the point-of-aim, while the center of group number 4 is located to the right of the point-of-aim. <ins title="i=5649" style="background:#E6FFE6;">(If Billy’s uncle had fired those ten, 3-shot groups, he would have cherry-picked group number 2 and group number 5 to represent the accuracy/precision of his rifle and ammunition and pretended that the other eight groups never existed.) </ins>Next, Billy’s parents had him form three, 10-shot groups from the thirty individual shots using the software program. (The first 10-shot group was formed from shots 1-10, the second 10-shot group was formed from shots 11-20 and the third 10-shot group was formed from shots 21-30.) The results are pictured below. The three, 10-shot groups.  Upon seeing the 10-shot groups pictured above, Billy immediately noticed how much smaller the variations in extreme spreads were from shot-group to shot-group. In fact, the extreme spread of the largest 10-shot group (group number 3) was only 1.5 times as large as the extreme spread of the smallest 10-shot group (group number 1). Billy even pointed out to his parents that the centers of the three 10-shot groups were all located very similarly from the point-of-aim. "That’s my boy,” cheered Billy’s mother. Billy’s father proudly remarked to Billy, "So now you see why 10-shot groups give us a much better picture of the actual radial dispersion of the shots fired from a rifle/ammunition combination.” Billy then asked his parents, "Should I try to explain this stuff to Uncle?” His father replied, "You can try . . . ” .... Just as in The Trouble With 3-Shot Groups and The Texas Sharpshooter, the shot-groups depicted in the above fable are from my actual targets obtained during live-fire testing. |
All that is necessary for Trolls to flourish, is for good men to do nothing.
In God We Trust. Everyone else must post data.
In God We Trust. Everyone else must post data.
| Nice... Really puts things into perspective. Thanks for the enlightening post. |
Our revolution will have been in vain if a Virginia farmer is held in hock to a New York stock jobber, who is in hock to a London banker. The opportunities for corruption would prove irresistible.
|
Originally Posted By R0N:
10 shots is just assurance of probability; if you want to know the actual dispersion pattern known as the 99.3 percent box you have to shoot 10k rounds. Then you need a new barrel.... start over again |
Our revolution will have been in vain if a Virginia farmer is held in hock to a New York stock jobber, who is in hock to a London banker. The opportunities for corruption would prove irresistible.
|
Originally Posted By R0N:
10 shots is just assurance of probability; if you want to know the actual dispersion pattern known as the 99.3 percent box you have to shoot 10k rounds. Data is expensive |
Filthy sinner saved by grace
"9mm gets the job done!" - Trayvon Martin (GTwannabe)
"9mm gets the job done!" - Trayvon Martin (GTwannabe)
|
Military contract standards require ten shot groups.
Why Oh Why does the AR community require strict allegiance to "MILSPEC" for parts components but sweeps the accuracy standard under the rug? Ten Shot Groups are MILSPEC, if someone is going to argue the benefits of magnetic inspection of every bolt then they would be the first on the ten shot group bandwagon. But, no, what we get are the jackwagons. 
Thank you once again for another informative and humorous illustration of the facts. In for thirty pages. 
|
| Flier..... ahhh I love that term. If only people know a bullet never lies only the shooter does. |
From flesh to steel and blood to blade I fight to exist... A rival of justice, extreme rush of hatred... Survival in a twisted world where nothing is sacred.
XM193 10 shot groups, shot 6/22/14
XM193 10 shot groups, shot 3/7/15 
I guess those "fliers" I attributed to "zoning out" behind the trigger were not fliers after all. I'm not the best shot and the rifle was not as stable as it could have been for the 6/22/14 groups, but that was not as much of an issue for the 3/7/15 outing which produced a pretty big ES in the last group. Hmmm. However the ATC is pretty decent, I think, for junky ol' XM193.
ETA: Upper used for the above groups was a newish 16" COLT LWT 6720 (And, yeah, I just noticed that I put the wrong rifle information on the target!  )
|
Member of Team Ranstad
Well done. 
My take on it all. Being Honest About Accuracy |
"I hate rude behavior in a man. I won't tolerate it." - Capt. W. F. Call, Texas Ranger
http://www.theboxotruth.com/
Shooting Stuff Is Fun
http://www.theboxotruth.com/
Shooting Stuff Is Fun
|
Originally Posted By Molon:
By all means, post your first-hand data showing the accuracy/precision results that you obtained from firing 10,000 rounds from a Krieger barreled, semi-automatic AR-15. .... Originally Posted By Molon:
Originally Posted By R0N:
10 shots is just assurance of probability; if you want to know the actual dispersion pattern known as the 99.3 percent box you have to shoot 10k rounds. By all means, post your first-hand data showing the accuracy/precision results that you obtained from firing 10,000 rounds from a Krieger barreled, semi-automatic AR-15. .... The reason guys like me are more concerned with data like that is most shooters think in the context of a vertical target, while I am more interests in horizontal targets and the so called beaten zone. Small variations that don't present themselves on vertical targets show themselves on horizontal targets and significantly increase the size of the beaten zone. |
In the real world off-campus, good marksmanship trumps good will.
|
Molon, What's your opinion on 5-shot groups? If one were to shoot, say six 5-shot groups (30 shots total), would that data be inferior to three 10-shot groups? Considering the sample size (n) remains the same? I ask because it seems as though you have more room for the shooter's influence on a 10-shot group, as fatigue (eye-strain), etc. can set in during the longer strings. I have noticed this myself (among other things, like groups opening up due to the barrel warming, etc.) I'm interested to hear your thoughts. I only use 3-shot groups to walk in a zero, or when confirming ballistics using said zero at different ranges. For those tasks, I don't want or need to burn up a great deal of ammo. When it comes to precision or "accuracy", I typically use several 5-shot or 10-shot groups. |
"One is a Colt, the other is not. Colt has always been known for quality where it counts, not for its level of fit and finish. " - Stickman
|
I was at an Appleseed shoot this weekend. We walked down to check our second targets of the day. Shooting to my right were were an active-duty soldier and an older gentlemen. The soldier had a group with four shots nice and tight and the fifth shot dispersed a bit. The older gentlemen pulls out a tape measure, approaches the soldier's target, declares the dispersed shot a "flier," and proceeds to measure the four tight shots.
This kind of stuff is probably more the rule than the exception. You even see it in published gun reviews. The Truth About Guns is a terrible offender for throwing out accuracy data they don't like. Instead of using the word flier, call it what it is. Just say when you measure groups, you only count the best four out of five shots (or eight out of ten or whatever your standard actually is). |
|
Originally Posted By Molon: Five shot groups are still inferior to 10-shot groups and for the same reasons that 3-shot groups are inferior. The differences between 5-shot groups and 10-shot groups aren't as dramatic as they are between 3-shot groups and 10-shot groups; but the differences are there, nonetheless. Here's a brief example illustrating the principles. Using SSA 70 grain TSX ammunition, I fired two 5-shot groups from the bench at a distance of 100 yards. Those groups had extreme spreads of 1.22” and 1.91”. I then fired a traditional 10-shot group, which had an extreme spread of 1.93” and a mean radius of 0.61”. Next, I over-layed the two 5-shot groups on each other using RSI Shooting Lab to form a 10-shot composite group. The 10-shot composite group had an extreme spread of 1.93” and a mean radius of 0.63”. http://www.box.net/shared/static/pjflm7508m.jpg http://www.box.net/shared/static/jcjqb2mh11.jpg …. Originally Posted By Molon: Originally Posted By Muad: Molon, What's your opinion on 5-shot groups? If one were to shoot, say six 5-shot groups (30 shots total), would that data be inferior to three 10-shot groups? Considering the sample size (n) remains the same? Five shot groups are still inferior to 10-shot groups and for the same reasons that 3-shot groups are inferior. The differences between 5-shot groups and 10-shot groups aren't as dramatic as they are between 3-shot groups and 10-shot groups; but the differences are there, nonetheless. Here's a brief example illustrating the principles. Using SSA 70 grain TSX ammunition, I fired two 5-shot groups from the bench at a distance of 100 yards. Those groups had extreme spreads of 1.22” and 1.91”. I then fired a traditional 10-shot group, which had an extreme spread of 1.93” and a mean radius of 0.61”. Next, I over-layed the two 5-shot groups on each other using RSI Shooting Lab to form a 10-shot composite group. The 10-shot composite group had an extreme spread of 1.93” and a mean radius of 0.63”. http://www.box.net/shared/static/pjflm7508m.jpg http://www.box.net/shared/static/jcjqb2mh11.jpg …. Interesting. Thanks for the explanation Molon, I appreciate your input. |
"One is a Colt, the other is not. Colt has always been known for quality where it counts, not for its level of fit and finish. " - Stickman
|
Originally Posted By tirod: Military contract standards require ten shot groups. Why Oh Why does the AR community require strict allegiance to "MILSPEC" for parts components but sweeps the accuracy standard under the rug? Ten Shot Groups are MILSPEC, if someone is going to argue the benefits of magnetic inspection of every bolt then they would be the first on the ten shot group bandwagon. But, no, what we get are the jackwagons. Thank you once again for another informative and humorous illustration of the facts. In for thirty pages. All we've ever used was 3 shot groups to get a BZO. And 10 rounds at 300m/yds to confirm zero. Why 10? Perhaps there are 10 rounds to a clip. |
Uncle
Sam's
Misguided
Children
I was cloning before cloning was cool:
Mk12, Mk13, Mk18, M4 Block II
Sam's
Misguided
Children
I was cloning before cloning was cool:
Mk12, Mk13, Mk18, M4 Block II
|
Originally Posted By dangerdan:
All we've ever used was 3 shot groups to get a BZO. And 10 rounds at 300m/yds to confirm zero. Why 10? Perhaps there are 10 rounds to a clip. Originally Posted By dangerdan:
Originally Posted By tirod:
Military contract standards require ten shot groups. Why Oh Why does the AR community require strict allegiance to "MILSPEC" for parts components but sweeps the accuracy standard under the rug? Ten Shot Groups are MILSPEC, if someone is going to argue the benefits of magnetic inspection of every bolt then they would be the first on the ten shot group bandwagon. But, no, what we get are the jackwagons.
Thank you once again for another informative and humorous illustration of the facts. In for thirty pages.
All we've ever used was 3 shot groups to get a BZO. And 10 rounds at 300m/yds to confirm zero. Why 10? Perhaps there are 10 rounds to a clip. It is a mix of a couple of things, the shot group are more about ensuring your point of aim than anything else, 3 shots gives you a 76 percent chance that that mean point of impact represents those sight settings 10 shots gives you 99 plus percent assurance of validity that that lot has captured the variations in all eight probable errors in all three axes |
In the real world off-campus, good marksmanship trumps good will.
|
Originally Posted By JohnBurns:
Always interesting to see a string of shots that all missed the point of aim but ended up in the same place. Some of us do that on purpose. I set my scope to hit about an inch high, so that I do not "chew" away the point of aim on the target. If I need to hit some exact point, I aim an inch lower. |
"I hate rude behavior in a man. I won't tolerate it." - Capt. W. F. Call, Texas Ranger
http://www.theboxotruth.com/
Shooting Stuff Is Fun
http://www.theboxotruth.com/
Shooting Stuff Is Fun
|
Glad to see you posting again Molon..Before I registered back in 2008, I lurked for about three years and follow your posts closely. Now-a-days, I only hang out in a few sub-forums but, with you posting here again, I definitely see myself coming around more often.
|
Freedom is not Free..
The 2nd Amendment is a RIGHT, not a Privilege...
Gun Gallery 4 Life: "Sellng Guns, Changing People's Lives"
The 2nd Amendment is a RIGHT, not a Privilege...
Gun Gallery 4 Life: "Sellng Guns, Changing People's Lives"
The Hunting Thread (Page 1 of 3)
AR Sponsor