3 shot groups

Tikka T3x CTR 223 Rem
55gr Hornady SP @ 2.199" OAL (.042 off lands)
27.16grs Win748
PMC brass / Dominion primer
3218 fps SD19 on 46 rounds

Fired ten 3 shot groups at 110 yards (letting barrel cool between groups)
  • 1.31moa
  • 1.9
  • .83
  • 1.87
  • 2.74
  • .4
  • 1.55
  • 1.37
  • 1.59
  • 1.44
3 shot groups averaged out to 1.5 moa, so using the 65% variability rule, 3 shot groups could be expected from 0.53moa to 2.48moa. I experienced groups from 0.4 to 2.74moa
 
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Remington 700 Varmint 22-250 Rem
Sako factory 55gr soft point
3647 fps SD25 on 32 rounds

Fired ten 3 shot groups at 110 yards (letting barrel cool between groups)

  • 0.82moa
  • 1.13
  • 1.06
  • 0.5
  • 0.88
  • 0.68
  • 0.76
  • 0.86
  • 1.15
  • 0.3
3 shot groups averaged out to 0.81 moa, so using the 65% variability rule, 3 shot groups could be expected from 0.28moa to 1.34moa. I experienced groups from 0.3 to 1.15moa
 
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Winchester Model 70 / Hardy 25.75" barrel - 6.5x55
125gr Nosler Partition @ 3.006" OAL (.050 off lands)
45.00grs Win760
W-W brass / Fed 210 primer
3007 fps SD23 on 26 rounds

Fired eight 3 shot groups at 110 yards (letting barrel cool between groups)
  • 1.85moa
  • 1.36
  • 1.3
  • 2.87
  • 1.35
  • 2.77
  • 1.69
  • 0.34
3 shot groups averaged out to 1.69 moa, so using the 65% variability rule, 3 shot groups could be expected from 0.59moa to 2.78moa. I experienced groups from 0.34 to 2.87moa

This rifle has shot a 0.9moa 9 shot group at 300 meters before with 150ABLR / Ramshot Hunter. It does not like the 125gr Partition, although a 0.34moa group would suggest there could be a node in there LOL
 
WhelanLad said:
10 is alot of shots for a Hunter
Click to expand...

Don't expect a single 3 shot group to give you solid info on how a particular load shoots. You may be seeing the best, or worst it will ever do

Also, if you zero off a single 3 shot group, it could be off by a bit and throw error into all downrange predictions and results on target will be off
 
todbartell said:
Also, if you zero off a single 3 shot group, it could be off by a bit and throw error into all downrange predictions and results on target will be off
Click to expand...

This cannot be overstated.

A ten round group might sound excessive, but statistically speaking a smaller sample size cannot yield high confidence.
 
So 3 shots groups are useless, 5 shots groups are great what about 8 shots group or 9 or 4 or 13 is the best more reliable info come increase with more shots in a group?
Like I said earlier I totally understand and agree with the 10 five shot groups being better than the 3 shot groups. I use 3 for a reason and so far it’s been plenty good for my hunting out to 300m on big games.
I like shooting but I can’t afford to shoot that much so I pick my battles hahaha and I make do with what I have. As long as I can put the bullet where it counts I’m happy) most of the time my bullseye is 24” in diameters so at 100-200 meters if I missed that it not 10 five shot groups that will fix it hahaha!
 
A common load development method for a long time is loading 3 shots at varying powder charges, working up to a "max load" and looking for the tightest grouping. This powder charge is the accuracy node. Some shooters will further tune accuracy by adjusting the seating depth in or out to find another node

I just want to show that 3 shot groups vary a lot and what you perceive as a sweet spot or node (or the worst result), may likely just be no more than the random noise of sampling 3 shots.

Every single handloader reading this post has done this method. We all grew up reading gun magazines where the rifles were tested with factory ammo and handloads and the results were 3 shot group of this and that. A lot of us probably bought rifles or avoided certain ammo because of the results of these tests. We have all found the holy grail combo, went home to load up the rest of the empty brass, only to be frustrated with results. We pull the bullets or sell the rifle and move on because it's "finicky"
 
Three shot groups can be misleading for sure.
This us one of a series of groups out of a 40X Remington Free Rifle in 308 Winchester.
300 meters . I shot several groups like this one yesterday , but the stock is a bear to shoot off a rear bag and I also had some 3 shot groups that were close to a minute .
The varying groups sizes were not because of the rifle accuracy however but the bottom of the stock.
Cat
 

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todbartell said:
I just want to show that 3 shot groups vary a lot and what you perceive as a sweet spot or node (or the worst result), may likely just be no more than the random noise of sampling 3 shots.
Click to expand...
The only use for three-shot groups is to exclude loads. So if you get 1.2" in a three-shot (and are aiming for under .5"), that load can be discarded.

The best advice is to not do three-shot "groups". They don't deserve the name of Group.
 
So many things to consider! If your rifle has a barrel that is affected by heating up then it's possible 3-shot groups are the most significant for estimating the rifles precision for 2 or 3 shots. For example, I have a Mosin PU Sniper rifle that has made many sub-inch 3-shot groups while zeroing the scope, but any time I take it to 5 shots it always opens up to around 1.5". This has happened way too many times for it to be simply statistics. For long shot strings we can look at how governments have evaluated their arms' accuracy. The Brits and USA have typically calculated the average radial deviation from the calculated mean point of impact. Way back when, the British called this the "figure of merit," and it has the decided advantage of minimizing the impact of always present "flyers." The Soviets took a different approach and recorded the diameter of the circle that contained, for example, 50 or 75% of the shots. This also throws out flyers quite effectively. Bottom line is group size is a horrible measure of rifle accuracy. To me, a "MOA" rifle is one that is showing a statistically significant concentration of hits within a MOA sized area on the target with flyers dealt with somehow. That PU Sniper of mine yields a figure of merit of sub one inch for 10 shot strings.

milsurpo
 
acrashb said:
The only use for three-shot groups is to exclude loads. So if you get 1.2" in a three-shot (and are aiming for under .5"), that load can be discarded.

The best advice is to not do three-shot "groups". They don't deserve the name of Group.
Click to expand...
They certainly are valid when zeroing a rifle!
I don't change the scope or irons settings after one shot, especially at 300 ,meters and beyond, and especially when zeroing a new rife and scope setup.
The above group I shot was but one group of 3 and 5 shot groups in 40 rounds.
The range session was about firing the first rounds out of a fresh barrel and to evaluate the rifle set up.
Cat
 
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todbartell said:
A common load development method for a long time is loading 3 shots at varying powder charges, working up to a "max load" and looking for the tightest grouping. This powder charge is the accuracy node. Some shooters will further tune accuracy by adjusting the seating depth in or out to find another node

I just want to show that 3 shot groups vary a lot and what you perceive as a sweet spot or node (or the worst result), may likely just be no more than the random noise of sampling 3 shots.

Every single handloader reading this post has done this method. We all grew up reading gun magazines where the rifles were tested with factory ammo and handloads and the results were 3 shot group of this and that. A lot of us probably bought rifles or avoided certain ammo because of the results of these tests. We have all found the holy grail combo, went home to load up the rest of the empty brass, only to be frustrated with results. We pull the bullets or sell the rifle and move on because it's "finicky"
Click to expand...
All great stuff in this thread. I think its great to challenge the old ways of doing things. For all those who don't frequent YouTube - there is a lot of great content on this stuff. I used to use the Tube for fixing cars and sleds and quads. Watching a couple things here and there.

https://www.youtube.com/@winninginthewind

One guy I follow (link above) - and he's an extreme F class shooter who dumps more money into his shooting than all of us combined. He says it like is being said here, you dont have to go through all of this and do what he does - this is just how he does it. From prep to shooting.

Finding the "node" with a one shot string method versus 3 shots or two shot to get the flat part of a node is one of my favorite video's that changed my thinking on this stuff. -

10 shot vs OCW meathod

I think for hunting you're doing yourself a disservice by not shooting more. I get it - its expensive. But as the golf analogy stated, I too had a friend on the course explain to me - "you're not good enough to be mad at this game", when I slice a drive after only playing 2 rounds a year. Same with shooting. Love the discussion. Enjoy the 3 videos - most are 15 min long. Not 2 hours of dragging it on and very good data.

Side note - I shoot my 338 once to make sure its dead on. I shoot it at moose - at usually 30-80 yards in the bush. I don't need a 3 shot group to tell me that.
 
milsurpo said:
So many things to consider! If your rifle has a barrel that is affected by heating up then it's possible 3-shot groups are the most significant for estimating the rifles precision for 2 or 3 shots.
Click to expand...

For this scenario, shooting multiple cold bore, or 2 shot pairs, 3 shot "groups" etc into one large sample is best like what I did in the original post with the Tikka 223

Great way to gather excellent data for hunting rifles. The more rounds fired, the more concrete the result which will be repeatable in future

I forgot to add :

todbartell said:
Tikka T3x CTR 223 Rem
55gr Hornady SP @ 2.199" OAL (.042 off lands)
27.16grs Win748
PMC brass / Dominion primer
3218 fps SD19 on 46 rounds

Fired ten 3 shot groups at 110 yards (letting barrel cool between groups)
  • 1.31moa
  • 1.9
  • .83
  • 1.87
  • 2.74
  • .4
  • 1.55
  • 1.37
  • 1.59
  • 1.44
3 shot groups averaged out to 1.5 moa, so using the 65% variability rule, 3 shot groups could be expected from 0.53moa to 2.48moa. I experienced groups from 0.4 to 2.74moa
Click to expand...

I shot two 25 shot groups with that ammo last year. 2.94moa and 2.98moa

25 shot groups vary 20% , so if it does average at around 2.96moa then future groups will be between 2.37 and 3.55. I also shot a 2.29moa 10 shot last year .

According to Hornady (gasp), Going from 10 to 20 round increases size by 20% (2.29moa turns into 2.75moa) and from 20 to 25 round it increases 5% (2.89moa)

I enjoy how predictable it becomes when you ramp up the sample testing
 
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For interest sake I just took the ES numbers from two pair fire F/O shooters in one of the V2 challenges .
This is 10 shots at 1,000 yards at a 1/2 MOA vbull and a 1MOA bull out of a possible 50 points for those not aware
First match was a 48 with a 27 FPS ES versus a 49 with a 35 FPS ES
Second match was a 49 with a 34 ES versus a 47 with a 53ES
The shoot off was only 5 shots and both ES strings were 23ES vs.23 ES
These two World class shooters were using there best hand loads in all three matches .
Cat
 
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iron cat said:
For interest sake I just took the ES numbers from two pair fire F/O shooters in one of the V2 challenges .
This is 10 shots at 1,000 yards at a 1/2 MOA vbull and a 1MOA bull out of a possible 50 points for those not aware
First match was a 48 with a 27 FPS ES versus a 49 with a 35 GPS ES
Second match was a 49 with a 34 ES versus a 47 with a 53ES
The shoot off was only 5 shots and both ES strings were 23ES vs.23 ES
These two World class shooters were using there best hand loads in all three matches .
Cat
Click to expand...
Great info, Iron cat. Thank you. 🍻

It’s nice to know I don’t need to start cutting powder kernels in half and weigh them with a 0.000000001 grain scale to get my ES super tiny. 👍
 
jimbo14 said:
Great info, Iron cat. Thank you. 🍻

It’s nice to know I don’t need to start cutting powder kernels in half and weigh them with a 0.000000001 grain scale to get my ES super tiny. 👍
Click to expand...
It has been said that F/Open is nothing but am equipment race, but at the end of the day, you still have to read the wind properly, and use a proper shot sequence .After all, the gun won't shoot itself, someone has to drive it!
Cat
 
I have used 3 shot groups for quick load development all my life. If you can't shoot a small group with three shots you certainly won't with more.

Shoot 3 shot groups for hunting rifles and repeat in days or weeks following on the same target... that quickly proves the load.

My hunting rifles often shot 1/2 to 3/4 inch groups depending on cartridge.
 
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