Lucky Group?

Picher · August 27, 2013, 07:29 AM

I went to the range yesterday to shoot several rifles and it was a mostly cloudy day with little wind from 7:00.

My buddy Chuck and I were shooting at 100 yards, checking zero and trying loads. I shot mostly loads for the .243 Win, wood-stocked, pillar-bedded, Pac-Nor stainless, (sporter contour 24", 1-9" twist) Super Match barreled, Rem 700 ADL. I also had my trusty .223 Rem, Tikka 595, and newly re-crowned Marlin 39A.

I was ecstatic with the .243, Rem 700 group. The best I've ever had from a sporter at 100 yards, measuring 0.15" for three shots. Load was 43 grains of IMR 4350, CCI LR, Win Cases, 85 grain Sierra HPBT.

The .223 Rem Tikka managed 3 out of 4 in 0.20". First shot out of a clean barrel went out about 3/8".

Shooting the Marlin 39A at 50 yards was frustrating at first. Using RWS 50, it shot an almost circular group of 1.9", then another with CCI Mini-Mags was equally bad. I suspected the scope was the problem because the crosshairs would jump when it dry-fired after the last shot.

Since the shots were 2" low on the Marlin, so I adjusted the scope to zero and promptly got a 5/8", 10-shot group with Mini-Mags that had all the rounds touching the 1" Stick-On bull!! All but two shots went into .30"! That scope's gotta go, but the Marlin is a keeper!!!

Some range days are better than others. This was one of the best!!!

Art Eatman · August 27, 2013, 08:27 AM

If your next several outings give the same or quite-similar results, you can forget about "luck".

I've always had tight groups with that Sierra 85-grain HPBT. Tagged a couple of dozen bucks with it.

dahermit · August 27, 2013, 09:03 AM

Quote:

I was ecstatic with the .243, Rem 700 group. The best I've ever had from a sporter at 100 yards, measuring 0.15" for three shots.

The fewer the number of shots, and the more accurate the rifle is in the first place, both tend to produce smaller groups. Therefore, if you want even smaller "groups" just shoot two-shot "groups" or even better yet, one-shot "groups".

I wrote a computer program once that would put five round spots (bullet holes), within a designated area (1"x 1") to simulate a rifle that could shoot 1 inch groups, and print each spot, as if it were a bullet strike, albeit completely random as to location within the designated area. Running the program and seeing how much just random chance effected the result and how frequently really good "three shot groups" would result in a phenomenal group only to be ruined by additional shots, It became apparent to me that shooting three-shot groups was just too likely to result in "false positives". That is why Benchrest Competitions always use five shots...such competitions and competitors have no interest in small groups that have a high likelihood of just being chance.

Also consider, if the standard is five shots, and someone states that they have shot a 0.xx three-shot group, how can we evaluate that when our frame of reference is, how large-small a really good five-shot group is?

For the non-competition minded hunters who will say that three-shots is a better way of judging accuracy because they do not shot five at game and they are shooting from a cold barrel, it begs the question: Why not use two shots then? Or, inasmuch as I love and have hunted with Browning and Ruger Single shots, why not only one?

And yes, your Marlin is definitely a keeper. Sorry about turning this into a rant.

Bart B. · August 27, 2013, 09:37 AM

If one's ever plotted shot holes' radius from calculated group center in a 100-shot group, they'll notice the following's pretty much what happens:

40% of the shots are inside a circle whose radius is 40% of the extreme spread.

30% of the shots are inside an area from the 40% circle out to the next larger 30% of the group extreme spread radius.

20% of the shots are inside the next 20% radius area.

And 10% are in the outside 10% of the group's radius.

The mean radius of all shots from group center is about 70% of the group's 100-shot radius across the extreme spread; the 40% plus the 30% radius.

This was called the 10-20-30-40 percent rule of thumb for shot groups as told to or read by me decades ago. It ain't 100% statistically perfect, but 95% is good enough for most purposes. Do it with a .22 long rifle at 100 yards; cheap and easy to see what happens.

One other thing... If you shoot several groups with a given load and they're not within 10% of the same size, you don't have enough shots per group to be statistically valid.

Picher · August 27, 2013, 11:53 AM

The last couple of outings provided several 3/8" groups from two .243s I own, but this was the best weather and accuracy so far. Still, there has to be an element of luck.

The situation with the Marlin was strange. Never had that happen before.

603Country · August 27, 2013, 12:31 PM

dahermit asks why we don't ever use 1 shot groups. Well..I do...right before hunting season. It's that last cold bore, lightly fouled, 'just to be sure' shot. Then the gun goes back in the safe.

And, regarding the 3 shot groups, it you put 3 shots into a tiny little group and do it again and again, it isn't luck. You have a good rifle and a good shooting eye (as my grandpa would say). That said, I'm a reloader, hunter, and paper puncher. I'm not a long range or competition guy, so my needs differ from many of ya'll.

And I will admit...though it pains me to say it...that there have been some very small and very fine 3 shot groups I shot when I decided that I'd just stop at 3. Not messing that group up...No sirree...Don't want that dreaded flyer to show up. (that gives Bart B the opening to now say that "there's no such thing as a flyer", but to me it's a flyer and will remain so.)

Bottom line is that I like to shoot, and a good 3 shot group is nice to see. So is a nice 5 shot group. I stay away from the 10 shot groups. Seems a waste of ammo to me. And my old 220 Swift will shoot nice small 3 shot groups again and again. Ain't luck.

dahermit · August 27, 2013, 02:00 PM

Quote:

And, regarding the 3 shot groups, it you put 3 shots into a tiny little group and do it again and again, it isn't luck.

One 3-shot group, again and again, is nine shots. I agree, that would not likely be luck. However, one five-shot group would have told you the same thing...and with less shooting.

Another reason to stick with five shot groups, is that new brass does not come in multiples of three...it comes in multiples of five. So, with five-shot groups (for test accuracy), keeps all the brass fired the same number of times. But, admittedly that is a minor reason.

In short, I have nothing against the practice of shooting 3 shot groups and expecting other shooters to "Oh and Ah" over them, just shoot two such groups, then post them both and I will be suitable impressed.

jmr40 · August 27, 2013, 02:02 PM

Five shot or more groups are fine for target shooters. I'm content with, and prefer, 3 from my hunting rifles. It is true anyone can get lucky. I've shot a few 3 shot groups in the .1's, but don't pretend they are typical. My average group size with multiple 3 shot groups, shot on different range trips over a period of months in varying weather conditions is my concern. Firing 5 shots tells me more about how well my rifles barrels resist changes from heat. I'm not at all concerned with that when my lightweight sporter barrels will never see more than 2-3 shots at a single game animal. The 1st shot from a cold barrel is far more important to me

dahermit · August 27, 2013, 02:04 PM

Quote:

And I will admit...though it pains me to say it...that there have been some very small and very fine 3 shot groups I shot when I decided that I'd just stop at 3. Not messing that group up...

Ahhh! Honesty! So refreshing!

dahermit · August 27, 2013, 02:10 PM

Quote:

Five shot or more groups are fine for target shooters.

And for hunters who are testing the capabilities their rifles, hand loaders testing loads. Once the those things are determined, then 3-shot groups are all that is required to assure the zero has not shifted, scope not damaged, etc. 3-shot groups have their place...just not as a statistically reliable indicator of accuracy.

Brian Pfleuger · August 27, 2013, 02:51 PM

One can easily see the trouble with 3 shot groups by simply imagining the mirror image of the group. Let's say you've got a shot at 8 o'clock, one at 2 o'clock and one 11 o'clock and the largest dimension between the 8 and 11 and the 2 and 11 are both 1/2". Assume the group is centered on the Point of Aim and the 2 and 8 shots are 1/8th inch from center. Simply, you've got a triangle with two 1/2" sides and one 1/8" side.

Now, imagine that you fired a 4th shot that went into the mirror image location of the 11 o'clock shot. It would be at 5 o'clock. Not a single bullet is any farther from the point of aim and that shot is the exact same distance from the 2 and 8 o'clock shots but it is MUCH farther from the 11 o'clock shot. In fact, your group has gone from being a 0.50" group to being a 0.968" group, without a SINGLE shot being farther from your intended point of aim than they had been with a 3 shot group.

Shots 1, 2 and 3 make a 1/2" group. Shots 1, 2 and 4 make a 1/2" group, all 4 of them make, essentially, a 1" group. That's a big difference considering that you didn't miss the target by any more than you had with the other 3 shots.

Even though I almost always shoot (and occasionally post exceptional) 3 shot groups, I know that they're actual meaning is extremely limited.

Picher · August 27, 2013, 04:51 PM

I'm a benchrest shooter, albeit rimfire, but have good bench techniques and if I get a great 3 shot group in the location I intend, it's good enough for me. Yes, 5 shot groups are the "standard", but I felt confident that the group at the place I intended, was good enough. Why waste ammo? I wasn't trying to prove anything to anyone...don't need to IMHO.

PawPaw · August 27, 2013, 05:01 PM

Quote:

Originally Posted by dahermit

I wrote a computer program once that would put five round spots (bullet holes), within a designated area (1"x 1") to simulate a rifle that could shoot 1 inch groups, and print each spot, as if it were a bullet strike, albeit completely random as to location within the designated area. Running the program and seeing how much just random chance effected the result and how frequently really good "three shot groups" would result in a phenomenal group only to be ruined by additional shots, It became apparent to me that shooting three-shot groups was just too likely to result in "false positives". That is why Benchrest Competitions always use five shots...such competitions and competitors have no interest in small groups that have a high likelihood of just being chance.

I believe that, and have no problem with it. Randomness is hard to measure when you can account for all the variables. I use a 3-shot group to show what DOES NOT work. If I'm playing with loads and I shoot some 3-shot groups, the ones that fall in two inches are immediately discarded. Those don't work.

Three shot groups are just a way of narrowing the field. Now, before everyone gets their panties in a wad, this time of year, I pick my hunting rifle for the year and start shooting one-shot groups. I want to know, to a dead certainty, where that first shot is going. I know that the second shot will fall close to it, but I want to really measure that cold-bore shot. Because, if I do the cold-bore shot correctly, I don't need another shot.

TheNatureBoy · August 27, 2013, 06:02 PM

5 shot group will probably be bigger than a 3 shoot group...10 shot bigger than a 5... That was the case with my .280. The more I shot, the bigger the group got. Final measurement for it was 1.342''/10 shot @100 yards. Its my go to hunting rifle (for the time being) and I'm happy with the results. I might tweak it a bit after hunting season. I measured from outer edge to outer edge. Center to center it would be even smaller. If I miss 300 yards and in it won't be the rifles fault. I'm a big fan of the .243 cal. and I think you're on to something. Thanks for sharing the load data with us

Bart B. · August 27, 2013, 06:34 PM

Here's a plot of 250 shots. Dimensions could be inches or millimeters. You pick 5 of 'em for your first group. Then I'll pick 5 others for my first group. We'll do that for 24 more times.

Who will have the smallest average of all 25 of their 5-shot groups?

Brian Pfleuger · August 27, 2013, 06:36 PM

Sounds like a fancy game of Tic-Tac-Toe to me.

A strange game.... The only winning move is not to play. How about a nice game of chess?

Art Eatman · August 27, 2013, 06:52 PM

King's pawn to King 4.

What I've come to believe after over sixty years of all this happiness is that the proverbial five-shot group is great to check out a new-to-me rifle. If all's well enough to make me happy with it, after that it's three-shot groups for sight-in and three-shot groups for load testing.

Aw, every now and then I'd do a five-shot string as a test of me, and sometimes even a ten-shot string. I was rarely disappointed. All my "pets" have been sub-MOA.

Ate lots of deer meat, cut off a fair number of coyote tails and messed up a few hundred prairie dogs. Good enough to suit me.

Serious target shooting? Different deal.

Sierra280 · August 27, 2013, 08:30 PM

I agree with the prevailing opinion. 2 more shots and luck wouldn't be a question

Picher · August 29, 2013, 10:08 AM

I'll take good, but was very lucky with respect to wind and mirage on our normally swirly Capitol City R&P main range.

The rifle with a 3-9X Leupold 2 (LR duplex) using the new load has recently shot two consecutive groups under 3/8". I was just out there shooting with a buddy and confirming my zero, since it was a bit windy the last time. After the group, I took a couple of clicks to the left. Vertical was perfect with the third shot going into the second hole (Rt.), barely enlarging it enough to confirm the shot.

The bottom bull has a three-shot group and a clean bore shot from my .223 Rem, Tikka 595, with a 4.5-14X Mueller. The final three went into the 0.2" cloverleaf. That was my favorite .223 Rem load, which is 25 grains of A2230, CCI Primer, and Hornady 50grain SP SX bullets in Winchester cases.

(Sorry, just noticed that the bottom group was actually 0.20" not .02". Big difference! I hadn't originally intended to show that target to anyone, since it had some rimfire shots at 100 and 50 on it, so didn't look at it very carefully.)

603Country · August 29, 2013, 10:31 AM

Nice shootin, picher. And I see that you use AA2230. I'm fond of that powder and get great accuracy with it, but few people mention it when they talk about favorite loads.

Picher · August 31, 2013, 06:33 AM

603Country: The first can of A2230 was given to me by a buddy. The first two boxes of .224 Hornady SX bullets were out of my B-I-Ls stash that was passed down. I put them together and it was "magic"!

Don't you just love it when you stumble on a fantastic load when you were just trying to get some cheap, shootable ammo? The best part is that the bullets are so inexpensive to buy, compared with some of today's fancy plastic-tipped "wowza" stuff.

August 27, 2013, 07:29 AM	#1
Picher Senior Member Join Date: December 14, 2004 Location: Maine Posts: 3,694	Lucky Group? I went to the range yesterday to shoot several rifles and it was a mostly cloudy day with little wind from 7:00. My buddy Chuck and I were shooting at 100 yards, checking zero and trying loads. I shot mostly loads for the .243 Win, wood-stocked, pillar-bedded, Pac-Nor stainless, (sporter contour 24", 1-9" twist) Super Match barreled, Rem 700 ADL. I also had my trusty .223 Rem, Tikka 595, and newly re-crowned Marlin 39A. I was ecstatic with the .243, Rem 700 group. The best I've ever had from a sporter at 100 yards, measuring 0.15" for three shots. Load was 43 grains of IMR 4350, CCI LR, Win Cases, 85 grain Sierra HPBT. The .223 Rem Tikka managed 3 out of 4 in 0.20". First shot out of a clean barrel went out about 3/8". Shooting the Marlin 39A at 50 yards was frustrating at first. Using RWS 50, it shot an almost circular group of 1.9", then another with CCI Mini-Mags was equally bad. I suspected the scope was the problem because the crosshairs would jump when it dry-fired after the last shot. Since the shots were 2" low on the Marlin, so I adjusted the scope to zero and promptly got a 5/8", 10-shot group with Mini-Mags that had all the rounds touching the 1" Stick-On bull!! All but two shots went into .30"! That scope's gotta go, but the Marlin is a keeper!!! Some range days are better than others. This was one of the best!!!

August 27, 2013, 02:51 PM	#11
Brian Pfleuger Moderator Emeritus Join Date: June 25, 2008 Location: Austin, CO Posts: 19,578	One can easily see the trouble with 3 shot groups by simply imagining the mirror image of the group. Let's say you've got a shot at 8 o'clock, one at 2 o'clock and one 11 o'clock and the largest dimension between the 8 and 11 and the 2 and 11 are both 1/2". Assume the group is centered on the Point of Aim and the 2 and 8 shots are 1/8th inch from center. Simply, you've got a triangle with two 1/2" sides and one 1/8" side. Now, imagine that you fired a 4th shot that went into the mirror image location of the 11 o'clock shot. It would be at 5 o'clock. Not a single bullet is any farther from the point of aim and that shot is the exact same distance from the 2 and 8 o'clock shots but it is MUCH farther from the 11 o'clock shot. In fact, your group has gone from being a 0.50" group to being a 0.968" group, without a SINGLE shot being farther from your intended point of aim than they had been with a 3 shot group. Shots 1, 2 and 3 make a 1/2" group. Shots 1, 2 and 4 make a 1/2" group, all 4 of them make, essentially, a 1" group. That's a big difference considering that you didn't miss the target by any more than you had with the other 3 shots. Even though I almost always shoot (and occasionally post exceptional) 3 shot groups, I know that they're actual meaning is extremely limited. __________________ Nobody plans to screw up their lives... ...they just don't plan not to. -Andy Stanley

August 27, 2013, 06:34 PM	#15
Bart B. Senior Member Join Date: February 15, 2009 Posts: 8,927	Group Therapy At Its Best Here's a plot of 250 shots. Dimensions could be inches or millimeters. You pick 5 of 'em for your first group. Then I'll pick 5 others for my first group. We'll do that for 24 more times. Who will have the smallest average of all 25 of their 5-shot groups?

August 27, 2013, 06:36 PM	#16
Brian Pfleuger Moderator Emeritus Join Date: June 25, 2008 Location: Austin, CO Posts: 19,578	Sounds like a fancy game of Tic-Tac-Toe to me. A strange game.... The only winning move is not to play. How about a nice game of chess? __________________ Nobody plans to screw up their lives... ...they just don't plan not to. -Andy Stanley

August 27, 2013, 08:27 AM	#2
Art Eatman Staff in Memoriam Join Date: November 13, 1998 Location: Terlingua, TX; Thomasville, GA Posts: 24,798	If your next several outings give the same or quite-similar results, you can forget about "luck". I've always had tight groups with that Sierra 85-grain HPBT. Tagged a couple of dozen bucks with it.

August 27, 2013, 09:37 AM	#4
Bart B. Senior Member Join Date: February 15, 2009 Posts: 8,927	If one's ever plotted shot holes' radius from calculated group center in a 100-shot group, they'll notice the following's pretty much what happens: 40% of the shots are inside a circle whose radius is 40% of the extreme spread. 30% of the shots are inside an area from the 40% circle out to the next larger 30% of the group extreme spread radius. 20% of the shots are inside the next 20% radius area. And 10% are in the outside 10% of the group's radius. The mean radius of all shots from group center is about 70% of the group's 100-shot radius across the extreme spread; the 40% plus the 30% radius. This was called the 10-20-30-40 percent rule of thumb for shot groups as told to or read by me decades ago. It ain't 100% statistically perfect, but 95% is good enough for most purposes. Do it with a .22 long rifle at 100 yards; cheap and easy to see what happens. One other thing... If you shoot several groups with a given load and they're not within 10% of the same size, you don't have enough shots per group to be statistically valid.

August 27, 2013, 11:53 AM	#5
Picher Senior Member Join Date: December 14, 2004 Location: Maine Posts: 3,694	The last couple of outings provided several 3/8" groups from two .243s I own, but this was the best weather and accuracy so far. Still, there has to be an element of luck. The situation with the Marlin was strange. Never had that happen before.

August 27, 2013, 12:31 PM	#6
603Country Senior Member Join Date: January 6, 2011 Location: Thornton, Texas Posts: 3,998	dahermit asks why we don't ever use 1 shot groups. Well..I do...right before hunting season. It's that last cold bore, lightly fouled, 'just to be sure' shot. Then the gun goes back in the safe. And, regarding the 3 shot groups, it you put 3 shots into a tiny little group and do it again and again, it isn't luck. You have a good rifle and a good shooting eye (as my grandpa would say). That said, I'm a reloader, hunter, and paper puncher. I'm not a long range or competition guy, so my needs differ from many of ya'll. And I will admit...though it pains me to say it...that there have been some very small and very fine 3 shot groups I shot when I decided that I'd just stop at 3. Not messing that group up...No sirree...Don't want that dreaded flyer to show up. (that gives Bart B the opening to now say that "there's no such thing as a flyer", but to me it's a flyer and will remain so.) Bottom line is that I like to shoot, and a good 3 shot group is nice to see. So is a nice 5 shot group. I stay away from the 10 shot groups. Seems a waste of ammo to me. And my old 220 Swift will shoot nice small 3 shot groups again and again. Ain't luck.

August 27, 2013, 02:02 PM	#8
jmr40 Senior Member Join Date: June 15, 2008 Location: Georgia Posts: 10,806	Five shot or more groups are fine for target shooters. I'm content with, and prefer, 3 from my hunting rifles. It is true anyone can get lucky. I've shot a few 3 shot groups in the .1's, but don't pretend they are typical. My average group size with multiple 3 shot groups, shot on different range trips over a period of months in varying weather conditions is my concern. Firing 5 shots tells me more about how well my rifles barrels resist changes from heat. I'm not at all concerned with that when my lightweight sporter barrels will never see more than 2-3 shots at a single game animal. The 1st shot from a cold barrel is far more important to me

August 27, 2013, 04:51 PM	#12
Picher Senior Member Join Date: December 14, 2004 Location: Maine Posts: 3,694	I'm a benchrest shooter, albeit rimfire, but have good bench techniques and if I get a great 3 shot group in the location I intend, it's good enough for me. Yes, 5 shot groups are the "standard", but I felt confident that the group at the place I intended, was good enough. Why waste ammo? I wasn't trying to prove anything to anyone...don't need to IMHO.

August 27, 2013, 06:02 PM	#14
TheNatureBoy Senior Member Join Date: September 6, 2007 Posts: 1,204	5 shot group will probably be bigger than a 3 shoot group...10 shot bigger than a 5... That was the case with my .280. The more I shot, the bigger the group got. Final measurement for it was 1.342''/10 shot @100 yards. Its my go to hunting rifle (for the time being) and I'm happy with the results. I might tweak it a bit after hunting season. I measured from outer edge to outer edge. Center to center it would be even smaller. If I miss 300 yards and in it won't be the rifles fault. I'm a big fan of the .243 cal. and I think you're on to something. Thanks for sharing the load data with us

August 27, 2013, 06:52 PM	#17
Art Eatman Staff in Memoriam Join Date: November 13, 1998 Location: Terlingua, TX; Thomasville, GA Posts: 24,798	King's pawn to King 4. What I've come to believe after over sixty years of all this happiness is that the proverbial five-shot group is great to check out a new-to-me rifle. If all's well enough to make me happy with it, after that it's three-shot groups for sight-in and three-shot groups for load testing. Aw, every now and then I'd do a five-shot string as a test of me, and sometimes even a ten-shot string. I was rarely disappointed. All my "pets" have been sub-MOA. Ate lots of deer meat, cut off a fair number of coyote tails and messed up a few hundred prairie dogs. Good enough to suit me. Serious target shooting? Different deal.

August 27, 2013, 08:30 PM	#18
Sierra280 Junior member Join Date: July 29, 2013 Location: Gardnerville, NV Posts: 569	I agree with the prevailing opinion. 2 more shots and luck wouldn't be a question

August 29, 2013, 10:31 AM	#20
603Country Senior Member Join Date: January 6, 2011 Location: Thornton, Texas Posts: 3,998	Nice shootin, picher. And I see that you use AA2230. I'm fond of that powder and get great accuracy with it, but few people mention it when they talk about favorite loads.

August 31, 2013, 06:33 AM	#21
Picher Senior Member Join Date: December 14, 2004 Location: Maine Posts: 3,694	603Country: The first can of A2230 was given to me by a buddy. The first two boxes of .224 Hornady SX bullets were out of my B-I-Ls stash that was passed down. I put them together and it was "magic"! Don't you just love it when you stumble on a fantastic load when you were just trying to get some cheap, shootable ammo? The best part is that the bullets are so inexpensive to buy, compared with some of today's fancy plastic-tipped "wowza" stuff.