3 shot groups vs 5 shot groups vs 10 shot groups

[KHornet]

I have long had a nobody wins argument with a very good friend and serious pdog shooter about 3 vs 5 shot groups and 10 shot groups. He has always claimed that he has never had over 3 shots at big game and that is the basis of his arguments. By the same token, I have seen him miss pdogs with up to 5-6 shots at ranges from 250 to 500, and with various wind and temp conditions. I have always believed in 5 shot groups. I have fired many three shot clover leafs at 100 with jacketed bullets, and a fair number with cast, both with various cals. However I have never fired a "Bug Hole" 5 shot group with any of my rifles in my 77 years, with well over 50 of those being shooting years. Came fairly close one time with my heavy bbl 243. 4 of the shots were a 4 leaf clover touching, but the 5th, was about 3/4" out. Was pleased none the less

In the latest Handloader Mag, there is an article on just this subject by John Barsness, that is by far the best pro and con look at the issue. This is a 50 year commemorative double issue feature, and includes a copy of the complete first issue of Handloader. Best reading of a gun magazine I have had in probably 30 or more years.

I shoot minimum 5 shot cast groups for testing, and about half of the time I will shoot 10 shot groups. Lately, I have been doing a lot of 50 yd cast shooting with a number of rifles. When I get a 10 shot group at 50 yds, at, under or close to an inch, I am pretty well convinced that I have an accurate load. I will be very interested in the responses to this thread, and the who, what, when, why, and whatever the responses are!

 

[Missionary]

Greetings
When beginning to shoot a new to me rifle I have used 3 shot groups just to identify a load that has possibilities. If it will not shoot 3 shots well it certainly will not shoot 5 well. Then the loads that look OK get the 5 or 7 shot treatment at 50 yards (open sights) or 100 yards (scopes). Then if they still look promising 10 shot groups will make or break the load. But generally I find.. If a load does well with 7 shoots it will do fine with a 10 shot group. Not every time.. there have been a few flukes.
A fellow shooter that uses our range in Illinois shoots 5 shot groups. Then goes to five, 5 shot groups to "prove" his load.

 

[JWFilips]

In my old age The 10 shot groups come natural. When I was in my 30's I very much suffered from 5th shot "itis"
I guess age has mellowed me & I'm not in a rush any more.... That is why you usually see 10 or 15 + shot groups on my targets ( of course others can say I just got lazy or or forgetful ...in that I should move to a new bull!

 

[Lost Dog]

I'll shoot 5. That way if i pull a shot and 4 are bunched up tight then I know that one all by itself was an "opps". When I'm down to a couple that really show promise, I'll shoot 10 at 100yds taking my time. Then I'll see what load is the one to lock into for the bullet/powder/other stuff to load regular. Unlike most, if I have a "proven " load I do not change anything. Only time I have to work up new loads is a new weapon, bullet, powder ect. Otherwise I continue with my proven load.

 

[Ben]

The powder and primer companies love the 10 shot groups.
I usually shoot 5 round groups.
My deer down here in Alabama won't hang around long enough for me to get the 10th round off.

Ben

 

[fiver]

i have done 50 and 100 shot groups before.

what i do now is analyze the rifle a bit more.
the 243 i have been using for rock chucks this spring will wander the shots some when the barrel heats up.
it's also not gonna take 5 straight shots in a row unless i miss 2-3 times when shooting a couple of chucks off a rock pile.
3 shot groups for consistency at 1-2-300 yds is enough, that's all i expect from this rifle.

my 220 swift is gonna see 5-6 shots knocking down tiny little metal cut outs at 300 yds, or the occasional 4-5 250-300 yd shots on some ground squirrels.
so 5 shot groups are fine for it.
i'l usually shoot a string of 4-5 of them on a trip to the range.
it's what i expect the rifle to handle, and certainly no more than 10 in a string [i like the rifle and want to keep the barrel on it]

now the 300 BO shooting slow and heavy [or medium weight and kinda fast] doesn't remotely heat up the barrel in 50 rounds.
so i have no issues shooting large numbers of rounds into a group, 50 isn't too many.
so i have no problem running off a whole 50 count box or two at a leisurely pace.
their jacketed counterparts however do heat up the barrel pretty quickly but will handle 5 rounds easily.
so i go with 5 shot groups there.

 

[Brad]

I often shoot 10 shot groups when testing load changes. I do this more so I can get a 10 shot stent over the chronograph than anything. I like seeing how a load holds up under stress. Lube purging will show up well in 10 shot strings.
For a hunting rifle 3-5 shots is plenty. I am prone to 5 shots there as most ammo boxes hold 5 rounds to a row.

Much depends upon what it is you are testing. Sight in for deer season might be a 3 shot group. Load development mght be 5 to 10. Testing for impact changes due to barrel heating might be 10 depending on load intensity. I like 5 shot groups for testing ME in preparation for hunting. If it is practice for an accuracy game I keep shooting on one target. More interested in eliminating the outlyers than anything. Let's me see how I hold up over a long string or series of strings too.

 

[Brad]

When we get down to it for hunting or varmint shootng a one shot group tells a bunch. It is a pass/fail test and that one shot tells all we need to know.

 

[Pistolero]

I like Barsness. Generally, his head is screwed on pretty straight, and I have learned from him. Haven't read the
article yet, saw it, but my starting point is that this is a statistical thing. If you want to really know what the gun can
do, you need AT LEAST 10 shots, and realistically, the statistics requires a lot more shots to be really valid. A 3 shot group
is very helpful for a large animal hunting rifle where 1-3 shots are all that are likely, and in that context, it IS meaningful.

BUT for a target rifle or prairie rat gun -- you want to know what the gun will do when hot and a 10 shot group is FAR more
helpful.

For the deer/elk gun, maybe shooting a 10 shot group, with 10 minutes cooling time between shots will be useful to see
what you can expect from your likely one and only shot, basically how far from the crosshairs will it likely land, from a cold,
fouled barrel. Then the three shot will tell you how followup shots, if necessary, will go.

Only on target or varmint rifles to I shoot larger round count groups.

Bill

 

[Lost Dog]

As a former analyst of criminal activity it's rather easy to make this statement. If you're studying something, the more data you can acquire, the greater the definition of results will follow. Trends & Patterns are what you need to arrive at your goals.
So, if you shoot 3 rounds for a string of 5 groups you have created a pattern. If all groups are similar or identical, you have a trend. Study of patterns and trends allow predictions of action. However, if the 3 shot groups were increased to 10 you introduce a greater number of variables to the study and thus allow a more accurate look at the data to show further defined patterns. With a pattern established I was able to see trends in criminal activity and predict, with some accuracy, the next event and where. This was only possible with the greatest amount of data to study. So the larger, disciplined groups shot and studied will produce the most useful and useable data to find patterns and establish the load's trend. The good part of studying this over criminal acts is the data is not effected by personalities!

 

[KHornet]

Tend to agree with you Bill. Part of the problem associated with the issue relates to the individual and if he/she is buying store bought ammo, or is a reloader, or if a reloader is a caster, etc.etc.etc.
Cost being a factor to most non reloaders with most high power rifle cartridges from the factory running well in excess of a buck and a half or two. Cost for a reloader with jacketed today is even somewhat cost prohibitive with large charges of expensive powder and costly jacketed bullets, and primers costing 3-5 cents. Even amongst casters, an afternoon shooting target loads of cast in a rifle can eat a fair hole in the wallet.

Believe you will enjoy Barsness's article, and will look forward to your comments after you have read it. Opinions of his article will vary depending on ones shooting/hunting perspective, type and cal that they shoot, where and what they shoot, experience(s) and objectives and on and on. I am at an age where about all I hunt anymore is Deer and Prairie Dog, and there is much difference in the requirements in accuracy for both.
Paul

 

[L1A1Rocker]

IMO a 10 shot group gets into an area of testing the shooter, rather than the rifle.

If you want to gauge the rifle only, stick with 5 shot groups.

If you want to gauge the shooter, then 10 shot groups are better. With 10 shot groups you will have variables coming into play such as eye strain and muscle strain twitches. (Folks under 40 probably have much less of these variables though)

 

[KHornet]

Very good comments Lost Dog! Find your last sentence to be pretty much spot on!

 

[Maven]

I saw & read Barsness' article as well and was impressed with its no nonsense treatment of the issue. What Lost Dog wrote is absolutely true about data & sample size (and representativeness). Joe Brennan, whom I'm sure many of you remember from Cast Boolits and the CBA Forum (He had the singular honor of being banned from both and the CBA Forum several times) asked when we should ignore flyers. The following, which I hope is helpful, is his answer:

OUTLIERS IN GROUP TESTING: WHEN TO EXCLUDE FLYERS
by Joe Brennan


Sometimes during a test we get a group with one shot way out, an outlier.
Our choice is whether or not to INCLUDE that outlier group in our results/calculations.
Here's a simple rule for 5 shot groups:

On the outlier target, measure the smallest 4 shot group and the 5 shot group including the outlier.
Divide the smaller into the larger.
If the answer is more than 1.7, DON’T INCLUDE the group.
If the answer is less than 1.7, INCLUDE the group.
Here's an example: A set of 5 shot groups has one group with a very wide shot. The four shot group size is .8". The five shot group size is 1.5". Dividing .8" into 1.5" we get 1.875.
Since 1.875 is more than 1.7, DON'T INCUDE the group.
For 10 shot groups, measure the nine and ten shot group sizes, divide the smaller into the larger. If the result is more than 1.43, DON'T INCLUDE; if less than 1.43, INCLUDE the group.

WHY?
A 5 shot group is 1.1 times the size of a 4 shot group.
A 10 shot group is 1.03 times the size of a 9 shot group.

The standard deviation of 5 shot groups is .269 X the average.
The standard deviation of 10 shot groups is .195 X the average.

 

[Brad]

What Joe says may be valid if looking solely at group size. When I shoot groups I am more often trying different load configurations and those "ignored flyers" may be telling me something.

What it really comes do to is this-decide WHAT it is you want to learn. Decide HOW to best measure that parameter.

Rick tests handguns at 200 yards because he had a specific need. Doing the same with a snub nose revolver would be an exercise in futility. The gun and end use determine the testing needs.

 

[Josh]

I prefer 2-4 strings of 5 shot groups, most of my rifles won't hold over 5 rounds, also I find if I am slamming in a particularly good 5 shot group it raises the pressure to drop in the other 5. On the other hand if I move over to a new dot, I am starting "fresh" and some of the perceived pressure is gone.

I rarely shoot 3 shot groups, when I do they are reserved for muzzleloaders and shotgun slugs, most everything else gets either a single 5 shot group (ladder loading) then a series of 2-4 five shot groups once I nailed down the load that was good in the ladder.

 

[RicinYakima]

What it really comes do to is this-decide WHAT it is you want to learn. Decide HOW to best measure that parameter.

That is the wisest statement I have seen on this subject.

 

[KHornet]

Have learned to my satisfaction that if the group (regardless of number of shots) is not more or less round, there is something less than satisfactory causing it, usually me!

 

[Lost Dog]

Have learned to my satisfaction that if the group (regardless of number of shots) is not more or less round, there is something less than satisfactory causing it, usually me!

That's been my view as well with a tight group and a stray off to the side. We're human and not a machine. We're gonna move, shift, twist, or wiggle just a bit when at the bench.

 

[9.3X62AL]

Many good thoughts in this thread. Reading this site is like studying in the presence of masters, and I am grateful for being being invited to enjoy its rich content.

Mi dos centavos......some random ramblings on riflery and pistolcraft as it relates to 3/5/7/10 shot groups and their interpretation/meaning. Biases up front--my shooting and its motivations are deeply skewed by my primary usages of firearms, which are as hunting tools--defensive tools--and (in the past) public service intervention firing (hereinafter "PSIF"). The assessment needs of these venues differ somewhat, but similarities exist as well. Which shot-count is best for each venue? That is arguable, as is the idea that shot count tests either/or shooter/tool. For my purposes here and afield, the blending of both is what matters.

Philosophy lesson over.

The needs of the deer hunter and the PSIF shooter are very closely related. Both venues call for the most precise placement of a shot (or shots) possible, and usually from a clean, cold barrel. During my time as a PSIF shooter, I sighted my rifles in--both scoped and iron-sighted--using a cold-shot grouping regimen that involved 5- or 7- or 10-shot patterns fired over a period of days on the same target with each shot coming from a clean, cold barrel that had rested for at least 24 hours between firings. Things aren't left at that point--no, you want to see what happens with subsequent shots fired through a fouled/warmed barrel as well--but you fire upon a second target to gauge that performance. A PSIF shooter has both a mechanical responsibility and a moral obligation to learn his/her rifle's behavior under all foreseeable usage circumstances, at varying ranges and under varying conditions. So, firing a series of 3- or 5-shot groups in an afternoon tells us practically nothing about what to expect from a system when things start to matter tellingly. What matters is the group fired as first shots of the day over at least 5 sessions--7 is better, and 10 is the gold standard. These WILL go to court in the aftermath of field usage.

A prairie dog hunter can learn MUCH from a series of 5, 7-, or 10-shot groups fired over the course of an afternoon, though. Different venue entirely--here, we are shooting a number of shots in close succession through fouled barrels that get occasional cleaning (or not.....).

In short, adapt your assessment regimen to the job being expected of the firearm in question. As needs vary, so too should your measuring method to derive the best possible outcomes.