Fx 700mm Barrels

I have an Impact and strive to get the best from what I think is the best diablo pellet on the market the “.25 King Heavies” 
This pellet has a bc in most barrels above .05 and has been the winning pellet in windy conditions at EBR for the last 2 years. 
What has this got to do with the new 700mm barrel about to hit the market? 
You would think maybe the current fx barrels are getting the best from this pellet already but I don’t think they are. 
In my opinion the best barrel for this pellet at the moment is the Lothar Walther polygon barrel and I’m not the only one. RAW fits these barrels to the hm1000x a gun designed around the King Heavy pellet. 
This gun can send a King Heavy pellet at around 900fps and produce sub moa groups with high frequency. 
So I fitted one of LW polygon barrels to my Impact. It worked well but I felt it lacked the speed I needed to produce the spin rate on the pellet to really get it stable at longer distances (100y)
With some modifications I have managed to get the speed up to 890fps and now I really happy with the accuracy. I can achieve sub moa groups at 100y and 60fpe of power. 
The down side to this is 
1: More Noise
2: More recoil 
3: Low shot count
4: A not so relaxing gun to shoot. 
So now what should the 700mm barrel offer? 
1: A 10% increase in velocity. 
So if in its standard form the Impact can shoot a King Heavy at 850fps you will now get 935fps! 
So realistically will have to turn down the power with reg and hammer spring for best accuracy. 
2: With less required air there will be an increase in shot count. 
3: Longer barrels are quieter barrels but add to this to the fact you are using less air and it will be quieter again 
4: Less air can also mean less air turbulence and a more accurate gun. 
5: Custom twist rates to match the pellet perfectly. 
6: Less recoil and a happier and easier gun to shoot. 
Down side
1: An extra 100mm of barrel. 
Not a big deal on an Impact really. 
Im excited about these new barrels. 
Im interested in what plans others have for the 700mm barrels 
Caliber?Slugs?pellets ?twist rates?
 
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It’s the rate of twist of the barrel that determines spin rate. For heavier projectiles you typically need a higher rate of twist to stabilize it unless it’s sufficient to begin with. Try reduced velocity if your pellet becomes unstable at longer ranges. I prefer fx barrels myself, but I do have a LW barrel coming-will see how it does. The best judge of barrels is simply which one wins the most. Personaly, I wouldn’t walk from here to across the street for the difference between fx and LW barrels from an accuracy standpoint. Indications I’ve seen are the FX barrels foul far less though.
 
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By the inch - 100mm about 3.9mm right?- 4 " of barrel lenght, with out others mods/adjustments should give you about a 40fps increase unless you are already really wasting air then you could see a 12-15fps per inch increase.

So if you are at 850fps you may see 890fps.

Might be a lot more to these barrels than the inch/mm tho?

John

 
Hey Ben. Agree twist rate is important but here is some simple maths that helped me nail spin rate. 

Twist rate of barrel: 1:12 
Velosity :1000fps
Spin rate exiting muzzle: 1000rev/second

Twist rate of barrel : 1:12
Velosity: 2000fps
Spin rate exiting barrel: 2000rev/second. 

Slowing the the speed down would work on an over stabilised pellet. Speed up velocity helps with an under stabilised pellet. 
If my velocity drops below about 870-880 they will start to spiral a little and are best at around 890-900fps
Both my barrel smooth twist and LW poly fowl at about the same rate although I am a compulsive obsessive barrel cleaner so it rarely happens. 
The smooth twist takes longes to lead up and be accurate again 7-10 shots LW 1-2 shots. 

Good of luck with your LW barrel. 
 
I just bought a used Impact with three barrels and eight mags. I also ordered the 700mm barrel with the slug liner. In .25 cal. I then noticed the Extreme Bench match in Utah, they seemed to be using impacts in .30. I'm retired. I'll figure it out. My Atamn ap 16 loved the 23 grain NSA slugs. Lothar walther barrel. So does my .25 AA S510. Both are underpowered for the slugs, but fire them very well. I want a RAW or Slayer next.
 
The Air Hunters have been testing the 700mm Slug-X liner in 22 caliber for a little bit now. From their videos is seems to be working well.

I don't know about 25 caliber.


Are these .22 700mm barrels currently available?


Well These two 700mm slug barrels in 22 cal and in 25 cal were delivered to me a couple days ago 

There must of been some of them released to the public . Sadly they are all gone " I bought the last two "

from Palm Beach Airguns . There is a down side to this I do not have a FX gun to put them in , not yet . 

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I bought my Impact with the 700mm barrel and it is shooting the king heavy at 950FPS. Way better than the 600mm

Interesting. I was hearing to shoot king heavys .25 at 850 FPS. (Maybe that was for the 600mm barrel.) Went to the range and was adjusting speed blindly. I ended up with good accuracy with this one particular setting. When I got home and chronied it. FPS turned out to be 950