barrel vibration dampeners tuners

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ronpistolero
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Joined: Tue Dec 16, 2008 8:36 am
Location: Philippines

barrel vibration dampeners tuners

Post by ronpistolero »

Hi. I shoot the pistol events but I would like to satisfy my curiosity with what I have been seeing to be getting more popular...the use of vibration dampeners attached to .22 LR rifles. The shooters swear by it. What do you guys think? I have been dabbling with air rifle bench rest shooting as well and many of them use such from a simple set of rubber "o" rings to a seemingly complicated tube/s.
Are these gadgets helpful especially for air rifles that shoot at 25 meter distances?
Ron
joel
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Post by joel »

Well, off the top of my head and from a purely physics standpoint, I can't imagine that an air rifle would introduce the harmonics that are present in a firearm. I'm thinking, however, that it might look cool and give your competitors reason to worry. :)

Joel
BigAl
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Location: Norfolk England

Post by BigAl »

I have shot both air rifle and smallbore BR under WARBF rules. Although the use of barrel tuners is common on the rimfire rifles they are much less common on the air rifles. Although I havn't shot it for three or four years. There was no one using tuners then with air rifles. I think the problem is that the barrels on the air rifles are too thin. For example I shoot an Air Arms S400 in .177running at around 780 fps with JSB Exact 8.4gr pellets. The barrel diameter is only 14mm on the standard rifle. Simply hanging a silencer or air stripper on the end seems to give enough extra weight to bring the node to the muzzel, with no real need to tune. Also the amount of vibration induced by both the operation of the knock valve and the pellets movement seem to be minimal.

Many of the air rifles that one sees with thicker barrels actually have a shroud over a much thinner barrel underneath. This is also true of all of the current PCP 10m match rifles that I know of. They just don't need the thickness as it's not like you need to use it as a leaver to comppress a big spring.

Air strippers which are also popular with the FT crowd (they look a bit like a sound mod with vents on the side) do though seem to be very effective as an add on to a PCP rifle. They also need to be fine tuned to set the distance of the stripper section from the muzzle for best effect. As they do not reduce the sound you don't need to pay the Federal silencer "tax" in the US so although normally quite a bit more expensive then a sound mod (which are uncontrolled for air guns in the UK) you will mostly see strippers not mods in the US. I will be sticking with the sound mod on my S400 though.

Alan
rmarsh
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Post by rmarsh »

Tuners on a smallbore rifle do work. Just go to a rimfire BR match.... You can't win one without a tuner. They are slowly becoming more popular among the 3p shooters. Vibration dampeners? The jury is still out, maybe they help.... maybe they dont.

Air rifle, I have not seen anyone with a tuner on a barrel. As was pointed out, the barrel is much thinner, and there is much less vibration than a sb. Another factor is in modern PCP guns, the velocity spread is very small. Could a tuner help? I may just have to try it and see!
BigAl
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Location: Norfolk England

Post by BigAl »

[quote="rmarsh"]Tuners on a smallbore rifle do work. Just go to a rimfire BR match.... You can't win one without a tuner. They are slowly becoming more popular among the 3p shooters. Vibration dampeners? The jury is still out, maybe they help.... maybe they dont.

Air rifle, I have not seen anyone with a tuner on a barrel. As was pointed out, the barrel is much thinner, and there is much less vibration than a sb. Another factor is in modern PCP guns, the velocity spread is very small. Could a tuner help? I may just have to try it and see![/quote

As I said in my post above a reasonable sized muzzel weight definatly helps. Having it adjustable seems to not make a lot of difference. Airgun World magazine ran an article a few years ago which concurs with the experiance of some of the top UK FT shooters that I know that showed that accuracy on a sporting/FT type rifle was imporived by a muzzle weight, then a sound mod, then a custom air stripper. With each step along the list adding a bit more consistency. These test would apply to rifles in .177 and running around 770-780 fps.

I don't see this as an issue for the current crop of 10m match PCP rifles such as the Walther LG400 or 300, FWB P800 or 700, or Styer LG110. All of these rifles have a relativly short barrel, so stiff for the diameter. They then use a longer shroud tube of much larger diameter over the top of the barrel itself. The tube has two effects, it may or may not help by letting the pellet emerge into still air. The other is to give somewhere to hang the foresight unit. The only affect of adding weight to the shroud is to get the balance point of the rifle just where you want it. Some find a heaviier muzzle helps with hold satbility by giving the muzzle added inertia. If you have a good hold it may help stop the muzzle from starting to move, but of course once it is moving it's also harder to stop again.

I do think we will start to see more combined bloop tubes/tuners on match smallbore rifles. For the prone shooter they should be a win/win for both inherent accuracy and rifle dynamics. The sight base gains, within any barrel length limitations is also liklely to be a benefit. For the positional shooter the accuracy boost is of course welcome. The added weight at the muzzle is the potential issue, will it adversly affect the balance/hold is likely to be the issue here. I guess if you can start new positional shooters with a rifle fitted with tube/tuner they will not have to then cope with something that is different. So I think that we will see them in positional shooting, but the uptake may be slower, with them being more popular with the newer (younger) shooter. That's of course if the ISSF dosen't ban them.

Alan
45ACP223
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Post by 45ACP223 »

FWB introduced a dampenng system on the 603 SSP air rifle to eliminate the harmonics from the forward motion of the pellet. The impact of the pellet was louder at 10m than the noise of the shot itself, it worked very well. I'm not sure it wasn't necessary on the newer PCP air guns.
joel
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Post by joel »

What's the purpose of these, to make them more accurate at 10m? Are you thinking that these air rifles are in need of more accuracy? As far as I've seen, they practically put pellets through the same hole. How much more accuracy do you need than that?

Joel
45ACP223
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Post by 45ACP223 »

Maybe this will explain. Here is a good primer from Jim E on the FWB600 series:

When introduced in 1984, the FWB 600 was billed as recoilless. But of course this was not strictly true. An 8.2 gram pellet accelerating to 175 meters per second causes an equal and opposite reaction to the 4.9 kilogram rifle. The resulting muzzle movement is nearly imperceptible for the club shooter. However, it is a different matter for the international shooter competing at the very highest level. These shooters drive technical innovation among the highly competitive precision air rifle manufacturers. Accordingly, Feinwerkbau introduced the FWB 603 in1997. The FWB 603 was very similar to the FWB 602 with the addition of a vibration dampening compensator to eliminate the miniscule muzzle movement caused by the accelerating pellet.

Here is the full post with history of the FWB series:

The Feinwerkbau (FWB) Model 600 air rifle was greatly anticipated when it was introduced in 1984. The first pneumatic match rifle, Walthers LGR, was then10 years old. While the LGR was truly a revolutionary match air rifle, not much had happened since its introduction except the refinement of existing spring piston rifles. These late spring piston match air rifles, the Anschutz LG 380 and the Diana Model 75, were certainly of high quality and very accurate. But spring piston technology of that era, with its complex recoil cancellation mechanisms and slow lock times, was no longer cutting edge. And air rifle competitors were tiring of the difficult cocking Walther LGR. Feinwerkbau, with its excellent but dated spring piston FWB 300, was in the position to introduce something truly new.

The FWB 600 included the following features:

A laminated hardwood stock with an adjustable cheekpiece and buttplate. The laminated stock was stronger at the wrist than walnut stocks used with the spring piston match rifles, and the distinctive appearance of the laminated stock announced a new era. The cheekpiece mechanism was simple yet easy to adjust. The butt-plate was vertically adjustable and could be adjusted for length using spacers.
A rifled barrel with a length of 16.6 inches. This inner barrel, however, was surrounded by a 25 long outer barrel tube that served several purposes. This arrangement allowed the loading port to be located near the rear sight, minimizing the time the slow moving pellet spent in the barrel, while allowing for a normal sight radius. The balance of the rifle could be adjusted moving (or removing) a sliding weight mounted on the outer barrel tube.
The cocking mechanism was hinged in the front with the power stroke on closing. This made it easier to cock than the Walther LGR, lessening shooter fatigue over a 60 shot match. It should be noted, however, that the cocking effort on the FWB 600 was greater than that of the spring piston match rifles.
An excellent two stage trigger, adjustable for pull weight and over-travel without tools.
A dovetail mounted match rear sight and an 18mm front globe sight. Sight riser blocks could easily be mounted to raise the line of sight.

Also revolutionary was the FWB C60, introduced in 1987. This rifle was equivalent to the FWB 600 except it used CO2 to propel the pellet rather than compressed air. The reason for offering CO2 as an alternate propellant was to eliminate the fatigue caused by operating the cocking lever during a match. While the fatigue of cocking the action for a single shot might seem minor, the cumulative fatigue caused by cocking the rifle up to eighty (for men, including sighters, a sixty shot match, and a ten shot final) times in a match is considerable. The FWB C60 eliminated this fatigue.

There were two other important side benefits of this new propellant. By disconnecting the CO2 cylinder, the shooter could train by dry-firing. More importantly, a shooter could now use the air rifle for 3-position practice. And while CO2 has been superseded by pre-compressed air, 3-position air rifle has evolved from a practice tool into a competitive discipline in its own right.

The FWB 601, introduced in 1988, was nearly identical to the FWB 600/C60 with the addition of a cocking arm latch to prevent accidental rebound of the cocking handle.

While the FWB 600/601 ruled 10 meter match air shooting after its introduction in 1984, by 1990 Walther, Anschutz and Diana had all introduced pneumatic match air rifles with the same basic layout as the FWB 600. This stiff competition led Feinwerkbau to introduce the FWB 602 in 1995. Improvements over the FWB 600/601incorporated into the FWB 602 included:

Pull length adjustments were controlled by a hex cap screw, eliminating the need for spacers. The cheekpiece mechanism was retained by a cap screw, making it easier to remove for adjustment.
The ergonomics of the stock were improved. A three point bedding system was implemented for mounting the barreled action in the stock.
A dry fire mechanism was added.
The trigger was improved to decrease lock-time. The ability to independently adjust overall pull weight and slack weight was added.
A completely new and vastly improved rear sight was introduced. The front sight diameter was increased to 22mm.

The FWB C62 was introduced at the same time as the FWB 602 and incorporated all of the improvements as the described above except the dry fire mechanism. To dry-fire a C62, shooters had to disconnect the CO2 cylinder.

When introduced in 1984, the FWB 600 was billed as recoilless. But of course this was not strictly true. An 8.2 gram pellet accelerating to 175 meters per second causes an equal and opposite reaction to the 4.9 kilogram rifle. The resulting muzzle movement is nearly imperceptible for the club shooter. However, it is a different matter for the international shooter competing at the very highest level. These shooters drive technical innovation among the highly competitive precision air rifle manufacturers. Accordingly, Feinwerkbau introduced the FWB 603 in1997. The FWB 603 was very similar to the FWB 602 with the addition of a vibration dampening compensator to eliminate the miniscule muzzle movement caused by the accelerating pellet.

Feinwerkbau replaced the FWB C62 with the P70 at the same time. The P70 was similar to the FWB 603 except that it used an air cylinder holding a pre-compressed air charge.

Pre-compressed air rifles proved very popular, both because they were easy to cock, and because they could be used for 3- position competition and practice. Although the FWB 603 is still listed for sale, pre-compressed air rifles now dominate the precision air rifle market.
ronpistolero
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Location: Philippines

Post by ronpistolero »

thanks for the replies. goal is wrabf accuracy at 25 meters
rmarsh
Posts: 220
Joined: Mon Jul 02, 2012 8:31 pm
Location: Arkansas

Post by rmarsh »

joel wrote:What's the purpose of these, to make them more accurate at 10m? Are you thinking that these air rifles are in need of more accuracy? As far as I've seen, they practically put pellets through the same hole. How much more accuracy do you need than that?

Joel
What level of accuracy? It depends on what competition you are shooting. If it is 10M International Air Rifle, very high levels of accuracy are absolutely necessary! Now that matches are scored in decimal it is possible to shoot a 10.9. Just shooting a 10 is no longer even close to good enough!

At Bavarian Airgun in Germany last month..... In women's open air rifle it took a 418 to make the finals. That is a 10.45 average! If you want to be winning on the international stage, men or women, somewhere between a 10.45 to 10.5 average is necessary.

This level of accuracy is not just limited to the top level shooters. In domestic and international events, even the Jr shooters are shooting average scores of 10.3 to 10.4 and up!

SO.... for someone who is (or wants to) play at the top levels of 10M air rifle; accuracy of the rifle / pellet combination is critical. Tested on electronic targets, 10 shot group sizes of 6mm, preferably under are necessary.
BigAl
Posts: 312
Joined: Mon Nov 26, 2007 5:37 am
Location: Norfolk England

Post by BigAl »

ronpistolero wrote:thanks for the replies. goal is wrabf accuracy at 25 meters
As you will be shooting at around the 770-780 fps level in .177 in WRABF competitions using probably 8.4 gr JSB Exact pellets I would suggest a good custom air stripper from one of the UK custom parts manufacturers would give you the best results, that would certainly be my choice if I had the money to spend. I guess though that I have been lucky as my Air Arms S400 is exceptionally accurate as it came from the factory, with just a standard AA sound mod, getting me to third place in the British Chamionships one year.

Alan
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