Adjustable Barrel Tensioning

[AdminMASTER]

GREAT READ ! >>>> http://www.airgunforum.ca/forums/topic65871.html

Ok Jon, I now follow what you were on about ref: Barrel Harmonics...etc....seems the easiest practical one, was & is, still bonded carbon fiber tube to barrel for stiffness & secondary cosmetic (per Walther LG300/LG400). Vinyl carbon look ...should be binned. or, kept...as long as owner knows it serves no purpose but in "looks".

The Fwb800 barrel tensioners...well...supreme engineering...but delicate to fine tune for most average shooters (like myself). Seems more appropriate to the Top League shooters wanting to squeeze the maximum potential over other shooters over a course...and it all adds up.

Its no accident you are indeed a Global knowledgeable expert !



-----------

" ....As i mentioned earlier I couldn't dismiss tensioning not working but confident its not that that will create the effect you will see. Do exactly the same without the disc springs! Just rotating the graduated purple weight.

Made loads from 7gr to 33.2gr. Heavy easy to learn the symptoms and effects but very hard to control spot on alignment. I usually aim for 12 to 16gr either on 1mm or 0.75mm pitch thread.

On 1mm pitch with 33gr, every 60 degree rotation will see a distinct pattern appear. Every subsequent 60 degree a further pattern and so on 4 times. Start to finish 2/3 of a rev that's 0.66mm your purple would move back and forth for max effect. Its also why those air strippers cannot work, at best pot luck no way can anyone make something that critical and assemble to that tolerance being 1/4 thickness of your hair.

One pattern will be -----, next Vertical, Next big spread, then single hole either low or above aim point.

I fit them to most of the P800 I have converted, to the untrained they look nothing special, great to keep an edge.

Done this June 2012 but made several different interchangeable weights.

Jan 2012 weight screws along barrel in to back venting quietener with 1/2"UNF at front with cap. Graduations every 30 degrees.

This ones in the grey bulbous thing at muzzle, most of the others directly in to barrel sleeve 15mm ish bore.

Customer quickly setting tuner up at 55 yards off the knee with unweighed, unsorted pellets. Looks like around 18 shot groups

He ended up with this though personally I would be far from happy having put a full charge down range 55 yards on my own with unweighed, unsorted pellets not leaving 3/8" edge to edge in a drift. Decent 5 shot group looking .22 pellet size hole.

some months back 0.75mm pitch, weights 12gr/pair. Should be looking within 1 1/2 revs setup due to lighter weight and reduced thread pitch.

"

[BenGun]

As an ex military shooter , I can tell you first hand that that barrel tuners work , no if's or buts , agree to disagree they work .
I use them , and I have just set up a mid barrel tuner on my FWB .

They are not just for the top end shooter , any one can use them , just takes a little time and practice to set up , graduate the markings on the shroud , then just dial it in , job done .

I can tell you this , wrapping in carbon fibre does sweet FA , if you want to be a poncy fashion guru , then go ahead , but to even think carbon fibre looks cool or does anything for harmonics your greatly mistaken.

Problem is 99% of people that have them , haven't got a clue how to use them , the bottom couple of photos are my rifle that Jon did for me , and the first couple of days on the range look very promising indeed .

I don't know if there is a time limit on each target in FT or HFT , as I'm a target shooter , if there is , that will be the only drawback , dialling in is taking time away from you .

[AdminMASTER]

...well, if its a question of dial to right...dial to left...dependant on range...sounds easy and good. So am supposing shooters dial the scope first, then dial your barrel....too cool !

[Jon]

Bri its not setup, when in tune all should be in a straight line exiting TDC or BDC.
Will also notice rifle shoots a lot better and follow the pellets all the way.

Some right knobs on that forum cant see further than their nose.

[BenGun]

Target photos arnt mine Jon, don't know where they come from.
Setting up on mine was pepper pot but in straight'ish lines.
I.E. 1 O'clock to 7 O'clock, or 2 through to 8, and so on.
Until they got closer and closer, shots out to 80 yards no problem really.
It's very close targets 8-10 yard, that I was finding difficult, but now I know what the rifle is going to do, that's not a problem now.
I did think, wrongly, that temperature would affect the set up, but it hasn't.
As the targets shot in the Jumbo Hanger prove.
Ben.

[Jon]

Heres mine after anodising just the front, round and round in circles most would write off as a shoddy barrel.


Same barrel, same pellets, same speed in strong wind trying to shelter over 51 yards, took 30 shots to tweak.
Rule no1 don't want to hit aim point so dialled left and spoilt it with last shot. Group as big at 30 yards as is 51 yards.

[Lol Moore]

Bri its not setup, when in tune all should be in a straight line exiting TDC or BDC.
Will also notice rifle shoots a lot better and follow the pellets all the way.

Some right knobs on that forum cant see further than their nose.

Apologies for resurrecting an old thread but I have been following this whole barrel harmonics thing for quite a while, its fascinating stuff and Jon seems to have a real handle on it.

The pellet exiting at TDC or BDC is sort of illustrated on the below video, I know its springers and not quite the same thing but the methodology and the graphics are a cool illustration.


https://www.youtube.com/watch?v=OYm_tI7mbBw

another view


https://www.youtube.com/watch?v=OksIysh0eTU

[Lol Moore]

Quiet day at work

I watched a program about earthquakes and building protection, to stop tall buildings falling over amongst other things they were fitting weight at the top of the building, some were sophisticated lumps of steel/concrete that had a sensing system and a series of jacks to move the weight counter to the movement of the building, the simplest (I likes simples I does ) was a tank of water, the difference this made was amazing as the freeboard of the water took time to catch up with the movement of the building and so damped the movement.

The BOSS system apart (as this has been discussed) did a bit of Googling on this sort of stuff in relation to barrels:


This one appears to operates akin to Jon's micro adjustables but very very unsophisticated:


https://www.youtube.com/watch?v=Xq2G2MubmuE


This is one I have not seen before, moving the pivot point instead of free-floating (about 7 minutes in):

https://www.youtube.com/watch?v=DhRIebOY4Jk

This is more like a flexible dampener as opposed to trying to get the nodes/antinodes to move to where you want them:

https://www.youtube.com/watch?v=HDNrLGhyR_o

Looked at Bowjax, not sure I would want a piece of floppy rubber on my barrel but interesting concept:

http://shop.bowjax.com/c/black-jax-gun- ... -dampeners

[NeilM]

John Whiscombe used to offer the HOTS system, and searching for details of that, I found this.

http://www.browning.com/support/frequen ... ystem.html

[Jon]

Very easy to do like the Boss, where the problems arise is when it all has to end flush.

Theres a springer video some where showing barrel flex before pellet exits.

Must say this vibration or flex is not a bad thing. On my JB Titan in 1992 well what was left of it being just the cylinder and breach block a Hammerli barrel noted as dire was put on. This barrel twanged and sounded like a tuning fork for around 3 secs after but the groups it would leave at 55 and 60 yards 10M shooters would be offering serious dosh to buy. Same barrel put on first air rifle made in 1992, groups much the same if not better how about 5.5mm hole 5 shots at 55 and 60 yards regular, nothing attached bare barrel. This is when people are posting superb groups 1/2" at 20 yards.

When people are changing pellet batches they are merely changing the sonic signature and exit point of the pellet nothing else. Same effect will happen when altering the velocity.
'Strippers' as in muzzle breaks do nothing except make the rifle shoot different ie counteract recoil if designed to do so most are not. Those that report better groups are not seeing air stripped especially as one name knocks em out with 9mm hole, even 6mm too big what they are seeing is the node changing. Typical airgunner fashion people quick to jump on bandwagon and new name given to the 1983 'Still Air' by the late Mick Dawes, credit where its due.