Tuning FX Impact - eliminating barrel flex?

[Stretch]

I recently acquired an FX Impact Mk II in .25 that I will be using for bench rest competitions. I love a lot of things about my new Impact, but one thing that surprised (and disappointed) me was just how much the unsupported barrel flexes. That's got to have a detrimental effect on accuracy.

I've scoured the internet and found two videos posted by Ernest Rowe that seem to address this, the first was about how to "tension" the barrel by adding a carbon fiber spacer between the shroud and the receiver. The other video was about the carbon fiber "sleeve" that is epoxied to the barrel liner and thus adds stiffness. I'm thinking about doing both of these mods.

Who has done either or both of these mods and how was the result? Or did you do something else to eliminate / reduce barrel flex? I haven't found anyone who has these carbon fiber parts in stock, any tips on where to get them?

 

[Theman406]

910 airgun tuning has the cf sleeves but they sell out fast 

 

[biohazardman]

I did it two different ways and both made the barrel much more stable.

First was just a bushing between the barrel and the shroud. Just slightly longer than the distance from the shroud to the block. So when the shroud is tightened it tensions the barrel. Simple but werqs very well.



Second one I replaced the aluminum shroud with a carbon tube.

https://www.airgunnation.com/topic/finished-up-on-my-impact-barrel-tension-mod/?referrer=1

 

[douger]

years ago they didnt use anything and i think the old smooth twist barrels were just as accurate just my opinion 

 

[Brent]

I saw where someone was testing the cf sleeve on the barrel but they didn't glue it on, they stated improvements even not glued.

 

[Stretch]

I did it two different ways and both made the barrel much more stable.

First was just a bushing between the barrel and the shroud. Just slightly longer than the distance from the shroud to the block. So when the shroud is tightened it tensions the barrel. Simple but werqs very well.

Looks like a bushing that's 20mm OD x 14mm ID would fit. Unfortunately the only source for a carbon fiber tube of those dimensions only sells 1 meter long tubes. Anyone know of a source for a smaller piece of tubing?

 

[Hobbyman2007]

I did it two different ways and both made the barrel much more stable.

First was just a bushing between the barrel and the shroud. Just slightly longer than the distance from the shroud to the block. So when the shroud is tightened it tensions the barrel. Simple but werqs very well.

Looks like a bushing that's 20mm OD x 14mm ID would fit. Unfortunately the only source for a carbon fiber tube of those dimensions only sells 1 meter long tubes. Anyone know of a source for a smaller piece of tubing?

Are you wanting to fill the entire shroud with the carbon tubing? I think you may have missed the purpose of the bushing. It only needs to be a short piece between the existing shroud bushing and the front of the action. Maybe a couple inches long at best. And for that you wouldn’t need carbon tubing , a piece of delrin ot similar even steel would work . As long as it slides over the outer barrel tube. 
The other method is to put a thin carbon fiber tube over the liner itself that replaces the o rings . 

 

[Airgunmann]

Like stated up farther 910 airgun tuning has them the lengths and calibers just select there like 50 bucks shipped

 

[Stretch]

Are you wanting to fill the entire shroud with the carbon tubing? I think you may have missed the purpose of the bushing. It only needs to be a short piece between the existing shroud bushing and the front of the action. Maybe a couple inches long at best. And for that you wouldn’t need carbon tubing , a piece of delrin ot similar even steel would work . As long as it slides over the outer barrel tube. 
The other method is to put a thin carbon fiber tube over the liner itself that replaces the o rings .

No, I understood the purpose of the bushing. I was hoping someone else here had made one from carbon fiber and had some leftover I could buy. I smallest / cheapest carbon fiber tube with the correct OD/ID was a full meter long, costs over $50 and would take over a month to get here. I decided to buy a small piece of aluminum pipe for $10 that should get here by the end of the week.

 

[Stretch]

Like stated up farther 910 airgun tuning has them the lengths and calibers just select there like 50 bucks shipped

Yep, email sent. Everyone is at RMAC so hoping he has some when he returns.

 

[Airgunmann]

I hope so to I ended up ordering one