Thread: 223 - unusual results

Originally Posted by Tentman

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

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

Originally Posted by tikka

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

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?

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

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

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!

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

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.

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

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".

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".

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.





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".



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 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

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

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.