FX FX Impact, do you tighten the barrel holder screws, FX suggest otherwise

[mubhaur]

In the following pic from the literature of Impact, it has been advised that barrel holder should not be tightened if tensioner is not used and it should be tightened for bigger calibers.

What pros and cons you feel while shooting Impact with tightened barrel holder ?

 

[ScopeFX]

Eh. I tighten them to 20 in/lb and call it good. I believe that’s what one of the master class videos said. Some people just snug it up and call it good. I wouldn’t leave them loose.

 

[mubhaur]

I understand that 20in/lb is due to tge FX barrel system so that the barrel shell could not be squeezed.

What if someone uses solid barrel like LW etc. ?

 

[broekzwans]

I understand that 20in/lb is due to tge FX barrel system so that the barrel shell could not be squeezed.

What if someone uses solid barrel like LW etc. ?

with a solid barrel just tighten until the bolt snaps, then back it out 1/8 turn so you could have prevented that

What do you want to achieve with tightening it further? As soon as the clamp properly engages it doesn't add any extra support anymore to tighten it further unless you start using the barrel tensioner assy. If you use that then tighten the bolts such that the tensioning system can't pull the barrel out of it's seat. I have my barrel holder tightened at 2.5 - 3 Nm I think and the barrel nut at 10 Nm by heart.

 

[bigHUN]

I am tightening those two screws, because ... I am tightening the shroud with integrated tuner (using a spacer to close the gap).

 

[Airgunmann]

I tightened them with a tensioner shroud and tightened them without it seems to work either way

 

[Airgunmann]

I suppose they might believe it is easier to torque it with it tight I guess it would depend on how tightly you shoulder the impact I guess

 

[qball]

I tighten mine but below the factory torque spec, zero issues.

 

[Ca_Varminter]

Since I use my tuning shroud and tension system...
Yes I do tighten the cap-screws... but only after I tighten my shroud to the First of Three stages
35 in-lbs Then I will Tighten the Barrel Clamp support cap-screws..
Then 60 in-lbs and final torque of 80 in-bs

 

[Vetmx]

I understand that 20in/lb is due to tge FX barrel system so that the barrel shell could not be squeezed.

What if someone uses solid barrel like LW etc. ?

I’ve been using barrel clamps on my impacts before FX even had them. You know the ones I’m talking about. On my solid steel barrels and my multiple tube FX barrels I do the same thing. Slide the barrel in, slowly tighten the screw until the barrel won’t slide anymore. Put a peen mark on the screw and one on the holder and that’s where I tighten them to from then on. I’m not trying trying to strangle or resize my barrel with a clamp, just trick the gun into thinking it has a shorter barrel on it. And 80 inch pounds of tension? That’s nuts. All my guns, even other brands, real barrels or FX, they all like about a quarter of that +or-.

 

[Ca_Varminter]

......... And 80 inch pounds of tension? That’s nuts. All my guns, even other brands, real barrels or FX, they all like about a quarter of that +or-.

Actually 80 in-lbs is quite reasonable......
If I hand tighten the shroud... it is very difficult to remove compared to 80 in-lbs by torque wrench!
Also I have added a second set screw to firmly secure the barrel.

Also I machined a groove into the steel barrel extension.. To insure the barrel will not go anywhere...

 

[Vetmx]

80 inch pounds is a lot pulling on all those pieces screwed together. But I guess it works for you or you wouldn’t be doing it.

 

[mubhaur]

Anyone can comment on accuracy and hold sensitivity of Impact with less torque vs more torque on these screws ?

 

[Vetmx]

Anyone can comment on accuracy and hold sensitivity of Impact with less torque vs more torque on these screws ?

No, if it comes down to that to make my Impacts shoot, I’m selling all of them.

 

[mubhaur]

I did some testing on various levels of tightness of the barrel holder.

To me increasing and decreasing the tightness of barrel holder changes the barrel harmonis and can be used as an additional tuning device.

With tight barrel holder, my gun becomes difficult to shoot accurately. Similarly unscrewing the screws also change the behaviour of the gun.

There are some points in between where the gun becomes easy to shoot accurately. It becomes very forgiving at certain tension levels.

At good tension level, the span of sweet spot of fps also become larger.

Bhaur