Realistic 10-shot groups

[Mike D Texas]

The reality is, VERY few hunting rifles, shot from bags, tripod/bag, etc are going to shoot better than 1" groups with most experienced shooters.

You will likely see those groups with super heavy, bench rest style rifles, maybe even rail guns with highly experienced shooters.

Tikka 223 compact 10 round ladder, no cool down between shots:

Remington 700 260AI with Brux Varmint contour barrel, ladder test, no cool down:

 

[3800fps]

The OP said:
2. I'm shooting with custom barrels (proof and fierce). But these are lightweight, high-recoil hunting rifles. Should I be demanding a 1/2MOA 10-shot group, or am I chasing a rainbow trying to make that happen?

You're chasing a rainbow….lots of excellent advice and knowledge is being given out here…take it.

10 shots, lightweight, high-recoil hunting rifles is a lot to overcome…if you're burning 60 grs plus of powder, by shot #4 things are hot, expanding and moving around…
The higher the recoil the more critical the platform interface with the shooter becomes…"steering the shot"

"1/2inch all day" is an interweb catch phrase that usually signals a bovine bowel evacuation happened or is forthcoming.

Hunting is a 3 shot endeavor with shot #1 holding all the weight.

 

[jeb405]

I do find this topic facinating. I have many years work experince with statistics and am amazed how I have never really put that knowledge ahead of dogma or tribal knowledge.

What I take from all this are a few things:

- averaging multiple 3-5 round groups is not the same as shooting larger groups, means almost nothing, worst it thinking the smallest I have seen is repeatable
- for hunting who cares what "MOA" your gun is, too easy to spend lots of time and money searching for better. If you have a bullet and velocity to do the job and groups at max distance that acheive what you need then be happy
- I'll no longer spend so much time on so many reload combination experiments, powder ladders, OAL ladders
- But if I want to understand what accuracy to expect when I train or compete, then I need to look at large groups so I know when problems are me, or when problems aren't.

I'll leave it there but facinating how many years I went thinking I knew things that now don't appear true. BUT still have a hard time merging the large sample size view with how there are very accomplished competition shooters who still use small groups to tell them which "load" shoots best.

JB

 

[Clutch]

The increase in group size with an increasing number of rounds is normal. Five shots is actually a very small sample size and if you truly want to have a very firm idea of where your rifle is going to place the next bullet, it takes a 20-30 round group to do it. FWIW, MOA 10-shot groups from a lightweight hunting rifle is very good.

Amen!! Statistics….

 

[billflangjr813]

On a hunting rifle, my personal acid test is more about where the rounds impact on a cold bore from one day to the next, with only 2 to 5 rounds being fired. If the rifle is intended to be fired with many consecutive shots, like for varmints or target shooting, I judge the groups over bigger strings, but only then.

Yea cold bore is the way to go.

 

[Rick Richard]

Usually my level of focus, shooting form and mental fatigue after 5 shots would more than likely keep me from doing my best…or the rifles best. Also, fear of pulling that one shot that will blow everything.

 

[COBrad]

The increase in group size with an increasing number of rounds is normal. Five shots is actually a very small sample size and if you truly want to have a very firm idea of where your rifle is going to place the next bullet, it takes a 20-30 round group to do it. FWIW, MOA 10-shot groups from a lightweight hunting rifle is very good.

Many years ago, I used 3-shot groups because conventional wisdom stated "I'll never take more than three shots at an animal." But, I noticed that when shooting another group with the same load, the point of impact might be slightly different, or maybe the group would open up, having two shots touching, and one a little out. Why? So, I started shooting multiple groups at the same POA and saw that the composite group showed me a much truer picture of what that rifle/load combo was truly capable of.

Providing the whole system is sound, a rifle will fire all of its bullets in a cone. With the 6PPC benchrest rigs, this cone will be very small, with others, bigger, but still a cone. The more rounds you fire, the bigger this cone will get until the sample size is big enough to represent a high level of confidence in statistical variation. What we, as hunters want, is to put enough rounds in a group to have a reasonable idea of where the next round is going. We're this not so, we wouldn't shoot groups at all, but just a single shot. In order to preserve barrel life, I do this by firing three, or maybe five, let the barrel cool, then fire three or five more at the same POA until I have a composite group of the sample size I want. The more shots in the group, the higher your confidence level can be. Most of the time now, I use a 10-shot composite. While not absolute, it provides a much higher level of confidence than the typical 3 or 5-shot group. 20 shots is better.

For those that say 3 is enough, I challenge you to do as I did years ago, and stack a couple of more groups on top of the first one, letting the barrel cool between groups, and see how big the composite is. It will absolutely be bigger than the single group and it is very likely that your "1/2 MOA all day" rifle really isn't.

A larger sample size doesn't just apply to group size either. The same principle applies to zeroing and load development. If you shoot enough rounds, you will discover that your .3gr increase in powder charge doesn't make nearly the difference you thought it did. I wanted to find max for a particular rifle once, so loaded 10 rounds, increasing by .4gr per round, figuring the first time I saw excessive pressure signs, I'd back off .5gr and call that max. The composite 10 round group with 10 different charges went into one ragged hole, well under MOA. I could have picked any one of those powder charges and expected similar results.

Actually, group size is no longer my preferred indicator of how well my rifle is shooting. Extreme spread only takes into account the data provided by two rounds, the two that make the widest spread. Average distance from center is better and you really don't have to measure it, you can see it. If during load development, I have a charge where the extreme spread of two different charges is similar but one of them has 8 of the ten wadded into a tiny little hole and the other is randomly scattered, I'm going to pick the first.

John

This is the same method I use, and pretty much the same recommended by Brian Litz.

 

[MarkInPA]

Don't trust anything said on internet forums.

This should be taken more serios by all of us. We should use discernment with anything we read. Online or in print. Lots of good information and lots of not so good information.

 

[MarkInPA]

Usually my level of focus, shooting form and mental fatigue after 5 shots would more than likely keep me from doing my best…or the rifles best. Also, fear of pulling that one shot that will blow everything.

I hear you. I've been there too. Probably most of us have been.

 

[Gary in MD]

Awe let's face it…
If you're not shooting 100 shot groups then you probably sit down to pee!

 

[Hikinghunter]

Good stuff here. Sounds like most folks aren't getting better than sub-moa 10-shot groups out of hunting rifles, even those with really good barrels. I guess all lightweight barrels are going to shift with heat, no matter how good they are. So in other words, im chasing a rainbow.

I like the idea of rotating rifles out and doing 5 cold-bore shots at the same POA. That seems like it would tell me the most about the rifle's accuracy in a hunting situation. I rarely get more than one shot.

I usually want my group to be half the size of the animals vital area. For an antelope or small deer, that means I want a 4-5 inch group at my max range. I'd like to have 800 yards of range, so if I get 5 cold-bore shots in 1/2moa, load development is over and it's time to practice positional shooting, dialing for wind, etc…

 

[Bwana Barry]

I maintain that too many average hunters puts too much pressure on themselves in trying to shoot 3 or 5-shot clover at 100yards for hunting purposes.
Having said that, I must stress that I never shoot any animal further than 250 (springbok / impala etc) to max 300 yards (kudu, gemsbok / wildebeest).
With CZ 6.5x55 lux and Fusion140gr, 1.5 to 2" grouping at 100 yds is acceptable for my hunting, and that floats my boat.
Obviously, if I was shooting longer ranges at paper or game, I would tighten up the grouping....

 

[biednick]

What's the point of a ten shot group? If your shooting half moa 5 shot groups, that's better then 95% of the people on this forum. 10 shot groups proves nothing and is just wasting components and barrel life. If it's taking you 10 shots in the field to be successful in the field, you should probably find a new hobby.

Having a realistic measure of your rifle's precision is useful in determining your max effective range. If you're holding 1.5 MOA off a bench at 100yd you probably shouldn't shoot a deer at 700yd in the field. 10 rounds isn't enough to really measure your rifle's precision, but it's a whole lot better than 3-5.

It has nothing to do with how many shots you take at one animal. It's about having a high degree of confidence the one shot you do take at an animal will will hit where you want it to. Low round count groups=low confidence in the measurements.

 

[Huntnful]

In your case, 10 shots is good for setting a legit zero, and seeing how well you can consistently reposition behind your rifle over a course of time.

Lately I've just been do 5 shot groups, shoot all 5 back to back with no cool down (it's just not necessary) and no repositioning of your body.

Doing that a couple time will let you know how consistently the load is.

Shooting the slow fired 10+ shot group will let you know how consistent YOU are, and will also give you a good idea of your realistic dispersion behind the rifle.

If you get up and down from the behind the rifle multiple time, and shoot a large enough group, over a long enough period of time, I bet 99% of the rifles out there would shoot over 1 MOA.

I'd like to see consistent repeated 1/2 MOA 5 shots several times. And then when doing a 10 shot zero, it'll be around .8-1 MOA more than likely from what I've seen from a hunting rifle.