Moderator as barrel tuner

[Popsbengo]

5 minutes ago, terryh said:

'.........there's too many variables not least the nut behind the trigger'

This is my limiting factor 😉

 

and mine

[brown dog]

42 minutes ago, Popsbengo said:

Quite a bit different to your original guesstimate of 2.5mS for 16".

I've drawn a more representative curve and recalculated = 1.57mS ± some beans

We need 1066 to chop the barrel at 1.5 " 😂

😂 yup. 

We now have your Kolbe of 1.75mS

Your drawn answer of 1.79

Your redrawn answer (to fit your preconception?😂😊) 1.57

And my calculated  of 1.88

.... three data points 'group' with one outlier.

Squad avg without outlier : 1.8mS

Squad avg with outlier: 1.74mS

....which is the Kolbe value, give or take🤔

To my mind, we've just idiot-checked the Kolby figure and validated it.

 

[Popsbengo]

3 minutes ago, brown dog said:

😂 yup. 

We now have your Kolbe of 1.75mS

Your drawn answer of 1.79

Your redrawn answer (to fit your preconception?😂😊) 1.57

And my calculated  of 1.88

.... three data points 'group' with one outlier.

Squad avg without outlier : 1.8mS

Squad avg with outlier: 1.74mS

....which is the Kolbe value 🤔

Damn! who'd have thunk it?  Bloody ballistics expert got it right,  😂🤣

[brown dog]

2 minutes ago, Popsbengo said:

Damn! who'd have thunk it?  Bloody ballistics expert got it right,  😂🤣

😂 yup;  but we've also shown it  ain't 5.56NATO rimfire either 😂😊

 

Right, I need to do some work ...

[1066]

So - Does an Anschutz type choked barrel negate the problem?

[Popsbengo]

2 minutes ago, 1066 said:

So - Does an Anschutz type choked barrel negate the problem?

that's what I've read - I think it's an excellent example of practical empirical method delivering benefits.

[ds1]

The Annie barrel was also thicker at the end - maybe for the choke but also might haven influenced the nodes.

Pops,  Walther wa2000 had a tensioned barrel- they have a couple in Royal Armouries I had a look at...... not sure that I would call it tensioned or supported.  Go look for yourself. Or extend the bar around the barrel- it’s called a tube and tension that - Lothar Walther also did that as did PGM Ultimate Ratio - they even contoured some sleeves. Just skip to structured barrels - someone has already done their homework and made a viable product for that.  .... it’s a bit beyond a muzzle break strapped to a micrometer though.

[Popsbengo]

9 minutes ago, ds1 said:

The Annie barrel was also thicker at the end - maybe for the choke but also might haven influenced the nodes.

Pops,  Walther wa2000 had a tensioned barrel- they have a couple in Royal Armouries I had a look at...... not sure that I would call it tensioned or supported.  Go look for yourself. Or extend the bar around the barrel- it’s called a tube and tension that - Lothar Walther also did that as did PGM Ultimate Ratio - they even contoured some sleeves. Just skip to structured barrels - someone has already done their homework and made a viable product for that.  .... it’s a bit beyond a muzzle break strapped to a micrometer though.

yes, seen those.  Just interested in alternative ideas that may have been tried - I'm not advocating for it just academic interest.

The structure of naval gun barrels and artillery barrels are interesting, the use of pre-stressed steel sleeves etc.

[ds1]

Pops another different  possible alternative is a mass driver - change spring  tension and alter the harmonics? It in effect does sort of what you and Matt talked about - changing barrel length as far as harmonics go..... you could regulate this.

 

[1066]

34 minutes ago, Popsbengo said:

that's what I've read - I think it's an excellent example of practical empirical method delivering benefits.

Rimfire benchrest rifle makers set great store in taper lapping their barrels - I believe the method that Anschutz use at one time to simulate that effect in a mass production environment was to heat shrink a sleeve on the last 2-3 inches of the barrel and constrict the bore.

[Popsbengo]

8 minutes ago, 1066 said:

Rimfire benchrest rifle makers set great store in taper lapping their barrels - I believe the method that Anschutz use at one time to simulate that effect in a mass production environment was to heat shrink a sleeve on the last 2-3 inches of the barrel and constrict the bore.

I expect it also means that the barrel can be made slightly 'looser' so reducing friction, reducing pressure, reducing stress impulses etc

Here's an odd one that needs some explanation:  my CZ455 16" is very accurate at 20yds bench rest with RWS rifle match.  However the first shot out of the stone cold barrel always goes high and left by about 1moa. I'm satisfied it's not the soft nut behind the trigger.  the problem is there with other ammo too but there's a general loss of precision.

If I leave my rifle for say an hour after 20 shots and shoot again, the 'flyer' is not seen, it's bang on target

I clean once a year if it needs it or not😀

 

 

 

[terryh]

PbG,

Your stray shot after a reasonable duration (put away and taken out) with 22rf is something I've seen/experienced. Mine is actually low 1st shot(from memory)

Is it that the wax lube 'sets off' ?

Also, when trying the new plastic coated stuff from CCI the first shot post normal wax ammo is low, the next about half way between the 1st and where I'm aiming and the third on the money - but not the other way i.e. wax directly after plastic. 

[Popsbengo]

20 minutes ago, terryh said:

PbG,

Your stray shot after a reasonable duration (put away and taken out) with 22rf is something I've seen/experienced. Mine is actually low 1st shot(from memory)

Is it that the wax lube 'sets off' ?

Also, when trying the new plastic coated stuff from CCI the first shot post normal wax ammo is low, the next about half way between the 1st and where I'm aiming and the third on the money - but not the other way i.e. wax directly after plastic. 

Could be the explanation.  I would expect the wax to have some affect.  When I clean it takes about 50 rounds to get back to acceptable performance.

I could clean, try CCI mini-mag and see.  Then again I'll just fire a not-fouling shot 😉 and carry on as mini-mag shoots really very badly in my 455 

[brown dog]

1 hour ago, 1066 said:

Rimfire benchrest rifle makers set great store in taper lapping their barrels - I believe the method that Anschutz use at one time to simulate that effect in a mass production environment was to heat shrink a sleeve on the last 2-3 inches of the barrel and constrict the bore.

How interesting.... one the things I was going to suggest as a solution to 'the resonant doughnut'  (or 'vibrating ring'?! 🤔😂)

I'd hazard a guess that these target-grade mfrs have known for a long time that a cure for a vibrating ring... sorry, unstable muzzle, is a choked bore. 

Pre-compressing the muzzle outer surface is almost a reverse-autofrettage. Makes total sense.

 

[brown dog]

https://forum.accurateshooter.com/threads/latest-test-on-1-cut-on-barrel-length.3946283/

[terryh]

2 hours ago, brown dog said:

https://forum.accurateshooter.com/threads/latest-test-on-1-cut-on-barrel-length.3946283/

Interesting data - if I had the patience I'd drop it onto a graph 😉

Personally I'd ignore the Stinger and other HV ammunition and focus on the SK standard, Midas and Tenex .which on the face of it go (nominally) slow-fast-slow in the process from 24" down to 17".

Shame the grouping was not carried out at the shorter lengths - but this is a person and probably got a bit choffed off in the chop and shoot process? 😄

There is some other interesting work being carried out, primarily by the Vudoo folks re. fast twist and barrel length in the strive for long range accuracy from 22rf's

[1066]

8 minutes ago, terryh said:

Interesting data - if I had the patience I'd drop it onto a graph 😉

Personally I'd ignore the Stinger and other HV ammunition and focus on the SK standard, Midas and Tenex .which on the face of it go (nominally) slow-fast-slow in the process from 24" down to 17".

Shame the grouping was not carried out at the shorter lengths - but this is a person and probably got a bit choffed off in the chop and shoot process? 😄

There is some other interesting work being carried out, primarily by the Vudoo folks re. fast twist and barrel length in the strive for long range accuracy from 22rf's

Also interesting to note, there were not ANY 1" groups at 100 yards, even with the match ammo. After 130 years or so and hundreds of millions of rounds you would think there wouldn't be much to learn about making the humble .22lr shoot sensibly. Top quality air guns have evolved rapidly over the last 15 years and can certainly give the .22lr a run for it's money in short range bench rest competitions, I think they may be ahead in 5 years. I also think, with the world wide pressure on range space, economics and the general political/media climate we are seeing new interest in the .22lr so maybe more development to come.

[terryh]

Allan,

I'm seeing locally more interest in 22rf for a few reasons, personally it is a bit of a challenge (couple of other shooting buddies also jave this view). As to the smaller groups at longer ranges. I hate to point to the US but here is a listing of 6 x 5 shot groups  https://www.snipershide.com/shooting/threads/6x5-thread-v5-0-new-1-1-21.6253073/ 

Also here's some of BD's linked data graphically:

[1066]

Yes Terry, I've followed the Snipershide thread with interest. It goes to show just how far behind we are here - I'm sure almost all of those shooters will have been using tuners of some sort.

[brown dog]

5 hours ago, terryh said:

Allan,

I'm seeing locally more interest in 22rf for a few reasons, personally it is a bit of a challenge (couple of other shooting buddies also jave this view). As to the smaller groups at longer ranges. I hate to point to the US but here is a listing of 6 x 5 shot groups  https://www.snipershide.com/shooting/threads/6x5-thread-v5-0-new-1-1-21.6253073/ 

Also here's some of BD's linked data graphically:

You an Arab? Interesting choice on the direction of the x axis! 😂

 

Interesting that SK is flattest

[brown dog]

Not seem that 6 x 5 thread before... that's some serious reality!   

("All under a thumbnail at 80m" - bolloqs!)

[terryh]

1 hour ago, brown dog said:

You an Arab? Interesting choice on the direction of the x axis! 😂

 

Interesting that SK is flattest

😂😂 Actually as an engineer I thought the barrel length should be ‘horizontal’ as that’s how I shoot and also how I’d hacksaw it down in size 😉

[brown dog]

16 minutes ago, terryh said:

😂😂 Actually as an engineer I thought the barrel length should be ‘horizontal’ as that’s how I shoot and also how I’d hacksaw it down in size 😉

Yeah, horizontal, but left to right, not right to left!😂  .

 

[terryh]

Got it 😫

now in 'English':

[brown dog]

Well, I realise this is statistically valid as a feeling in my water,  and I'm afraid I stopped just after I started due to it starting to snow....

I wanted to see what, if anything a 'tight rubber band' deresonator might do. 

Group on the right is 'without bands'... then did one on left 'with bands' ( and then, annoyingly, I packed in) ..... the left group is typical of the better groups (25%) I get with the rifle.. it was just felt odd that it happened straight after I put the bands on, and despite the weather deterioration...I know, chance... but interesting if it turns out to be repeatable 

45m/49yds   bipod, back bag