223 - unusual results

A few weeks ago I tested a cobbers 223 - a nice wee Sako 75. As I recall it's never been a reliably "good shooter" but perfectly OK for hunting.

I had some Belmont 62gn ammo that wasn't up to much in my 223 so commenced with it.

After 5 shots I happened to look at the chony and holy cow, the ES was really low, so I kept going to 15 rounds. For the 15 the ES was 14.9 and the SD 4.7, As far as my experience goes that about the best ever result I've seen or any 223 ammo including reloads.

The group however, a distictly average at 44mm (at 100M) so - thoughts (apart from poor shooting haha) on how such a low ES translates into that sort of group?

Read up on barrel harmonics

If barrel harmonics are unrepeatable/variable shot to shot then the poi suffers regardless of how exact each velocity is

Haven't you watched the Hornardy #50 podcast. Harmonics are so yesterday.

Greetings,
ES and SD are poor indicators of accuracy especially at short range as you discovered.
GPM.

Quote:

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Originally Posted by Tentman

Haven't you watched the Hornardy #50 podcast. Harmonics are so yesterday.

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ES and SD are what you work on after you have tuned the load to the barrel, they are in the info stack at the end that shows you why you have that 4 inch group at 1000 yards

https://dsiac.org/articles/random-er...er-dispersion/

Velocity consistency is only one of many factors. You could have 15 rounds with identical Velocity (hypothetically) and if the bullets are poor quality with COG offset due to inconsistentjacket thickness for example, they will have relatively high dispersion. Or if the bullet experiences principle axis tilt on it's journey down the bore. Or... etc

None of these are "harmonics".

All the theory is nice but really it's most practical to look at results measured with a decent sample and take pragmatic actions. You can speculate about what a theoretical cause for poor precision is but you can't change it, just get different ammo

Quote:

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Originally Posted by gimp

https://dsiac.org/articles/random-er...er-dispersion/

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Man that's an interesting article - quite a bit to digest in there, might take an evening or two to fully understand!

Was it 62 gr FMJ ammo? FMJ often shoots poorly compared to HP or SP.

Also, what twist rate is the Sako?

Quote:

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Originally Posted by gimp

Velocity consistency is only one of many factors. You could have 15 rounds with identical Velocity (hypothetically) and if the bullets are poor quality with COG offset, they will have relatively high dispersion. Or if the bullet experiences principle axis tilt on it's journey down the bore. Or... etc

None of these are "harmonics".

All the theory is nice but really it's most practical to look at results measured with a decent sample and take pragmatic actions. You can speculate about what a theoretical cause for poor precision is but you can't change it, just get different ammo

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Yeah. I'm gonna pull the 62s and try some Vmax 60s - I'll keep a close eye on the 3harmotics for those who worry about such things!

It was SPBT, probably Hornardy. Twist is 1:8.

What's the user's requirements for performance? What size target do they want to reliably hit, out to what range?

And what's the mean radius you measured with those 15rd?

The barrel could be touching the barrel channel in the stock?

Quote:

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Originally Posted by tikka

The barrel could be touching the barrel channel in the stock?

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Checked that, and bedding. All looks OK.

Quote:

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Originally Posted by gimp

What's the user's requirements for performance? What size target do they want to reliably hit, out to what range?

And what's the mean radius you measured with those 15rd?

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He's quite happy just going hunting and knocking animals over and will be completely oblivious to the fact that I find this combination "interesting" !

Quote:

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Originally Posted by Tentman

It was SPBT, probably Hornardy. Twist is 1:8.

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Had a bunch of it..only a few left now. Shot really well out of my Ruger American Ranch II..16" barrel, 1:8 twist. Suppressed

Oh well you need to get someone else to test it then

Failing that I would look very closely at the crown and the last section of the bore

Quote:

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Originally Posted by tikka

The barrel could be touching the barrel channel in the stock?

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Since you have tested for this and found it's free-floating, why not try a pressure pad on the end of the forearm?
I use a small folded piece of bicycle inner tube (don't make it too long).
If that pressure point on the barrel doesn't work I keep the pad in and cut a few more lengths of tube. Then slide the tube over the end of the barrel and place it on the fore-end.
You can fire 3 shots then adjust the tube forward or back until groups tighten up.
It works on barrel harmonics again...successful on many of my rifles.
What have you got to lose except an old bicycle tube?

Attachment 257399

Who says 44mm for 15 shots is even bad?

Sako actions can be a wee bit fussy with bedding
Front of action rear of action and section of barrel
In front of the action usually a good bet
Depending on style of recoil lug used in there stocks
Between models 75 85 ect and stock types
Make sure lug system is permanently fixed before bedding
Or if it has been epoxy bedded check for movement
In the lug or retaining plate/lug
Had a 243 come in the other day that the grub screw
Retaining the lug had loosened off a pinch in a 75
Could just detect it 2.5” groups to 3/4” after pulling it
Apart cleaning area and re applying loctite

Quote:

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Originally Posted by NCGNSMITH

Sako actions can be a wee bit fussy with bedding
Front of action rear of action and section of barrel
In front of the action usually a good bet
Depending on style of recoil lug used in there stocks
Between models 75 85 ect and stock types
Make sure lug system is permanently fixed before bedding
Or if it has been epoxy bedded check for movement
In the lug or retaining plate/lug
Had a 243 come in the other day that the grub screw
Retaining the lug had loosened off a pinch in a 75
Could just detect it 2.5” groups to 3/4” after pulling it
Apart cleaning area and re applying loctite

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Thanks for that. I pulled it to have a look at how it worked, and saw the grubscrew but never checked it. Tomorrow job now!

Quote:

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Originally Posted by akaroa1

Oh well you need to get someone else to test it then

Failing that I would look very closely at the crown and the last section of the bore

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Thanks for that vote of confidence in my shooting . . . .

I did borescope it with my very basic teslong, and it's quite rough in places with pitting. Overall though I'd expect it to shoot better. It came off here ( can't recall who from) . I was hoping they might chip in.

Quote:

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Originally Posted by Hermitage

Since you have tested for this and found it's free-floating, why not try a pressure pad on the end of the forearm?
I use a small folded piece of bicycle inner tube (don't make it too long).
If that pressure point on the barrel doesn't work I keep the pad in and cut a few more lengths of tube. Then slide the tube over the end of the barrel and place it on the fore-end.
You can fire 3 shots then adjust the tube forward or back until groups tighten up.
It works on barrel harmonics again...successful on many of my rifles.
What have you got to lose except an old bicycle tube?

Attachment 257399

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Thanks but until people start posting up 15 plus shot test groups of their results I'm done with the generally promoted versions of "harmonics". Read the article Gimp posted above. It has one paragraph on matters "harmonic".

Quote:

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Originally Posted by Tentman

Thanks but until people start posting up 15 plus shot test groups of their results I'm done with the generally promoted versions of "harmonics". Read the article Gimp posted above. It has one paragraph on matters "harmonic".

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Ok, challenge accepted.
I'll shoot a 15-shot group tomorrow (in the rain) without the forend pressure tube. Then shoot another 15-shot group with it and post it on this thread tomorrow evening.
Then we can look at 'harmonics'...

So I went to the range today to test if the rubber tubing shown in Post #18 above effectively dampens out barrel vibrations/harmonics thus leading to smaller groups.

I used two .22LR rifles at a distance of 50 yards:
1 - Norinco JW-15s with suppressor and Bushnell AR 3-12x scope.
2 - Anschutz 1450 with suppressor and Bushnell AR 4.5-18x scope.

Attachment 257495

Attachment 257496

As both rifles already had the DIY bicycle tubing pressure on their fore-ends, I started the groups with the tubing on (right-hand target groups).

First was the JW-15s:
I fired a 10-round 'warm up' group with a hunting round - Fiocchi subsonic hollow point (these warm-ups are not on the target).
Then I proceeded to shoot the 15-round group on the top right of the target with the Fiocchi which came to 22.4mm/0.88" (after I took out the 2 flyers).
Next, I left the tubing pressure on and changed to Norma Tac-22, a mid-range target ammo. I didn't allow the barrel to cool down, so I did not fire a warm-up group. The 15-round Norma group second down on the right was 17.8mm/0.70".

I then removed the tubing pressure pad on the JW-15 leaving the barrel free-floating (the first 1 inch of the barrel was bedded along with action). I also let the barrel cool down.
I then fired a 10-round 'warm-up' and sighting group with Fiocchi (shot off target). Without the tubing pressure, it was firing high so I had to lower the elevation by 10 clicks (1/4 MOA clicks).

Now was the moment of truth...what effect would the tubing fore-end pressure have?
I shot the 15-round group on the top left with Fiocchi and it came out at 16.7mm/0.65" vs 22.4mm/0.88" for the tubing pressure pad! I was disappointed as my DIY tubing didn't decrease the group size and if it did dampen the barrel harmonics, the result-based logic shows it doesn't seem to matter!
I then shot the final JW-15 group with the Norma Tac-22 and free-floated barrel. The group measured 18mm/0.70" basically the same as the group with the tubing pressure (17.8mm/0.70").

I did the same procedure above with the Anschutz 1450.
Two groups with the tubing pressure using Fiocchi and Norma and two groups free floating.
Fiocchi free floating 21.3mm/0.83" vs Fiocchi with tubing pressure 23.4mm/0.92".
Norma free floating 17mm/0.66" vs Norma with tubing pressure 19.4mm/0.76".

Attachment 257497

Conclusion:
I have concluded from this experiment, that the whole barrel harmonics thing is very overblown. I tested this concept by making a biological thing (me the shooter) use the rifle. I mean, we're talking about precision, even if I'm the best shooter in the world :thumbsup: I'm still a living thing, which means I'm the biggest variable involved. And the groups were so close that I'm sure it only comes down to the variable of the shooter in the end.
So as for 'harmonics'... pffff... myth busted in this DIY experiment using these two rifles.

Interesting results but pretty consistent with my experience over a wide range of 22s and now a few centrefires. I see you excluded some shots, these don't really change your results but after a while you might come to the same conclusion I have . . . I don't "pull" shots but especially with 22s I do get flyers that can't be explained.

Thanks for collecting some data and testing the theory.

Probably why the likes of Browning BOSS muzzle break/adjustable harmonic thingy didn't really survive. A lot of faffing about for marginal gains.
It maybe worked sometimes but not enough to be worth the hassle

Quote:

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Originally Posted by csmiffy

Probably why the likes of Browning BOSS muzzle break/adjustable harmonic thingy didn't really survive. A lot of faffing about for marginal gains.
It maybe worked sometimes but not enough to be worth the hassle

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And fark me, that thing was a noisy, uncomfortable, disruptive, smelly, smokey, pumice blasting pig of a thing at the very best of times. Usually the BOSS system was worse in reality. What a prick of an idea...

As far as FMJ, the target boys worked out that trimming the point of the FMJ rounds they used for fullbore back a very small amount to make them slightly wider and slightly hollow pointed improved them no end. I'm not sure why this would be, and the other point was that it was rumoured that the pill could shed the jacket inside the barrel which could lead to bulging.

I pulled the Sako 75 in question down for a look-see and sure enough as @NCGNSMITH mentioned, the grubscrew on the recoil lug was only finger tight. It's now had a dose of locktite but I haven't retested it yet.

Quote:

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Originally Posted by Hermitage

So I went to the range today to test if the rubber tubing shown in Post #18 above effectively dampens out barrel vibrations/harmonics thus leading to smaller groups.

I used two .22LR rifles at a distance of 50 yards:
1 - Norinco JW-15s with suppressor and Bushnell AR 3-12x scope.
2 - Anschutz 1450 with suppressor and Bushnell AR 4.5-18x scope.

Attachment 257495

Attachment 257496

As both rifles already had the DIY bicycle tubing pressure on their fore-ends, I started the groups with the tubing on (right-hand target groups).

First was the JW-15s:
I fired a 10-round 'warm up' group with a hunting round - Fiocchi subsonic hollow point (these warm-ups are not on the target).
Then I proceeded to shoot the 15-round group on the top right of the target with the Fiocchi which came to 22.4mm/0.88" (after I took out the 2 flyers).
Next, I left the tubing pressure on and changed to Norma Tac-22, a mid-range target ammo. I didn't allow the barrel to cool down, so I did not fire a warm-up group. The 15-round Norma group second down on the right was 17.8mm/0.70".

I then removed the tubing pressure pad on the JW-15 leaving the barrel free-floating (the first 1 inch of the barrel was bedded along with action). I also let the barrel cool down.
I then fired a 10-round 'warm-up' and sighting group with Fiocchi (shot off target). Without the tubing pressure, it was firing high so I had to lower the elevation by 10 clicks (1/4 MOA clicks).

Now was the moment of truth...what effect would the tubing fore-end pressure have?
I shot the 15-round group on the top left with Fiocchi and it came out at 16.7mm/0.65" vs 22.4mm/0.88" for the tubing pressure pad! I was disappointed as my DIY tubing didn't decrease the group size and if it did dampen the barrel harmonics, the result-based logic shows it doesn't seem to matter!
I then shot the final JW-15 group with the Norma Tac-22 and free-floated barrel. The group measured 18mm/0.70" basically the same as the group with the tubing pressure (17.8mm/0.70").

I did the same procedure above with the Anschutz 1450.
Two groups with the tubing pressure using Fiocchi and Norma and two groups free floating.
Fiocchi free floating 21.3mm/0.83" vs Fiocchi with tubing pressure 23.4mm/0.92".
Norma free floating 17mm/0.66" vs Norma with tubing pressure 19.4mm/0.76".

Attachment 257497

Conclusion:
I have concluded from this experiment, that the whole barrel harmonics thing is very overblown. I tested this concept by making a biological thing (me the shooter) use the rifle. I mean, we're talking about precision, even if I'm the best shooter in the world :thumbsup: I'm still a living thing, which means I'm the biggest variable involved. And the groups were so close that I'm sure it only comes down to the variable of the shooter in the end.
So as for 'harmonics'... pffff... myth busted in this DIY experiment using these two rifles.

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The usual method is to place something between the bstock tip and barrel. Some come that way from the factory.

Quote:

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Originally Posted by Oldbloke

The usual method is to place something between the bstock tip and barrel. Some come that way from the factory.

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You could go test this too and see what happens.

What is also interesting is the little polished JW15 just outshot the Anschutz. Best group at 16.7mm v 17mm, but four group average of 18.7mm versus 20.3mm for Annie. :)

Have seen that happen so many times!! :) Last one I polished tested out at 0.47" average over three smaller groups!

I'd say that the precision is unable to be determined as being any different between the 2. Without taking actual mean radius measurements from each rifle/ammunition combination and reasonably comparing - at a glance it appears that there is insufficient evidence to confidently declare any difference.

Which is still a win for the Norinco on value.

Quote:

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Originally Posted by csmiffy

Probably why the likes of Browning BOSS muzzle break/adjustable harmonic thingy didn't really survive. A lot of faffing about for marginal gains.
It maybe worked sometimes but not enough to be worth the hassle

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My ears hurt just remembering those things.