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Hello guys,
I have some issue with my ssg24.When i was with long inner barrel and M180 spring my rifle on chronograph shows around 3,2 Joules.Then i decide to make it short i bought a short inner barrel. Now im testing it on chronograph and my joules are so low.Can someone explain to me please. Sorry for my bad english :)
 

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In a physically inaccurate but close enough explanation:

F = MA
2AS = V^2

Where V and M is the velocity and mass of the projectile respectively, A is the (initial) acceleration, F is the force in newtons provided by the spring, and S is the distance travelled.
For the purpose of this explanation acceleration is assumed to be constant (which generally isn't, as force dissipates due to expansion or friction or other reasons else) and the pressure is enough to push the BB out of the barrel before it leaves the barrel.

For both real rifles and airsoft rifles, the barrel length determines how much acceleration the projectile can experience due to air pressure behind it, where as long as the air pressure is sufficient the projectile will be constantly pushed out of the barrel until it leaves the barrel.

With a shorter barrel, the "acceleration corridor" is shortened, thereby the BB experiences a shorter period of acceleration and could only be launched at a slower speed than when it was being launched through a longer barrel. Hence your observation of the resulting Joule count being lower than what it had been is a completely normal phenomenon.

To compensate, you can either use an even more powerful spring or use washers, both with the intent in increasing the amount of energy (hence BB acceleration) provided to the BB and compensate for the reduced length, but this comes at the cost of increasing wear and tear of parts due to extra stress, as well as making it harder to pull the bolt backwards.
In general if Joules is a major concern to you it's advisable to use a longer inner barrel instead.
 

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Depending on BB weight there is also an optimum barrel length. Anything under you need a higher spring to compensate anything over and you lose power and accuracy.

Post your setup including what BB weight you are using and what joule rating you are trying to achieve.

If your testing on .20g than it's all pointless anyway as heavier bb's chrono different (AKA joule creep).
 

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These cylinder to barrel to bb weights length are for the VSR10. If you use the ratio for your rifle, you should be able to get the correct barrel for your bb weight.
So see the chart below:...................................................Ratio
0.3gm bb use a 554mm barrel (15821 mm^3) = 2.26:1
0.32gm bb use a 530mm barrel (15136 mm^3) = 2.36:1
0.36gm bb use a 500mm barrel (14279 mm^3) = 2.51:1
0.4gm bb use a 470mm barrel (13422 mm^3) = 2.67:1
0.43gm bb use a 430mm barrel (12279 mm^3) = 2.92:1
0.45gm bb use a 400mm Barrel (11423 mm^3) = 3.13:1
 

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These cylinder to barrel to bb weights length are for the VSR10. If you use the ratio for your rifle, you should be able to get the correct barrel for your bb weight.
So see the chart below:...................................................Ratio
0.3gm bb use a 554mm barrel (15821 mm^3) = 2.26:1
0.32gm bb use a 530mm barrel (15136 mm^3) = 2.36:1
0.36gm bb use a 500mm barrel (14279 mm^3) = 2.51:1
0.4gm bb use a 470mm barrel (13422 mm^3) = 2.67:1
0.43gm bb use a 430mm barrel (12279 mm^3) = 2.92:1
0.45gm bb use a 400mm Barrel (11423 mm^3) = 3.13:1
I know you worked really hard on obtaining the above information, but I am curious as to why you still see power loss on the SSG10 platform when going to a shorter barrel? Not only does Nov show this on his charts, but my brother experienced this when teching his rifle. Isn't in VSR10 spec, thus it should have gained energy?

I understand where your numbers are coming from (both the theory and testing you've done), but it seems anomalous with everything else I've both seen and experienced.
 

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Not sure exactly how people can sometimes use a longer barrel. (It may have something to do with barrel diameter. I used 6.03mm from what I remember but even if I use 6.01mm, I normally still use the same ratio or I just add a couple of centimetres to the length). These are normally the best barrel lengths. (Do you have a link to one of his charts)
Some people have said that using different piston weights can alter the cylinder to barrel to bb weight ratio. But I have not experimented enough regarding the different piston weights and barrel lengths to confirm this.
It took me long enough to experiment with just a normal layax piston and different barrel lengths to get the results I did in the experiment and so adding that extra variable would have increased the work load too much for me.
 

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Not sure exactly how people can sometimes use a longer barrel. (It may have something to do with barrel diameter. I used 6.03mm from what I remember but even if I use 6.01mm, I normally still use the same ratio or I just add a couple of centimetres to the length). These are normally the best barrel lengths. (Do you have a link to one of his charts)
Some people have said that using different piston weights can alter the cylinder to barrel to bb weight ratio. But I have not experimented enough regarding the different piston weights and barrel lengths to confirm this.
It took me long enough to experiment with just a normal layax piston and different barrel lengths to get the results I did in the experiment and so adding that extra variable would have increased the work load too much for me.

Scroll down for the charts for the various rifles and barrel lengths. My brother experienced about a 50fps drop when shortening his barrel, which corresponded with what Nov's charts predicted.
 

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Scroll down for the charts for the various rifles and barrel lengths. My brother experienced about a 50fps drop when shortening his barrel, which corresponded with what Nov's charts predicted.
It does not have barrel lengths. He has different spring rates.
 

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I'm kinda confused, but 430X6.01 is definitely more air efficient than 300, so that's why there's a power loss.

The ideal piston weight for a VSR seems to be 50-75g, giving you the most power out of your spring.
Are you talking to me about the 300mm inner barrel? I agree, 430 is way better unless you are using 0.66gm bb's.

The ideal piston weight does change depending on the strength of the spring. The stronger the spring, the heavier the piston should be. But 50-75gm is about right for a high end sniper. I think I mainly use 65gm.
 

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The default barrel gives more energy in those charts than the shorter barrel. If a barrel is too short for the bb weight, the bb will exit before the piston has completed its travel. This waists precious cylinder air and gives less acceleration time in the barrel. Thus not achieving max acceleration.
 

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It does for 2/3 rifles:

View attachment 19799

View attachment 19800

I was mistaken for the SSG10 - I believe the reduction in FPS is covered in one of his Academy videos.
Interesting how the ssg10 appears to always be a few fps lower than the SSG96 & 24 I wonder if it's because he is selling aps2/t96 springs and just making people shove them in vsr's so they don't perform optimally as designed for a longer cylinder.

Also those charts don't say what weight the heavy gram BB actually is so that second joule reading is useless.
 

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Gaddam I got the Ssg10 a2 with the short barrel cause on the novy site it says barrel length does not effect accuracy. So now thats not true then is it, if its dropping 50 fps..

EDIT And yet when I chronod it today, it read 360 fps with .45s, which is almost exactly the 2.8j advertised. Unless the beat up field provided chrono was inaccurate.
 

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FPS does and doesn't mean accuracy, same with barrel length.

As long as you're in the ideal FPS range of 300-370 with your chosen BB weight and you are running a barrel that isn't undervolumed then you really don't have much to worry about.
 

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Gaddam I got the Ssg10 a2 with the short barrel cause on the novy site it says barrel length does not effect accuracy. So now thats not true then is it, if its dropping 50 fps..

EDIT And yet when I chronod it today, it read 360 fps with .45s, which is almost exactly the 2.8j advertised. Unless the beat up field provided chrono was inaccurate.
Barrel length doesn't affect accuracy it just changes how hard of a spring is needed to reach desired fps (as a very simple explanation but their is more to it).

Also NOV has said all his springs should shot hot/higher compared to the rating they are given. This is so customers can cut the springs to match their fps/joule requirements. (Which semi defeats the point of a pre "upgraded" off the self rifle, if it still needs any work done). It's likely as your using short barrel the fps is up as with a long barrel you would be over the joule limit due to his springs shooting hotter than stated.
 

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According to the chart 1ton posted, my short novy barrel (at 300? Mm) is about 25% shorter than what would be most powerful with my .45 bbs (400mm). If the longer barrel adds about 50fps, and Im already shooting at 2.8, then I'd be looking at about 3.5J with a long barrel. Pretty hot indeed
 

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As said above, lower fps is to be expected.But that results in no practial disadvantage.
I wouldn't try to compensate any joule loss with stronger springs. The difference between extremes like 2.2 vs. 3.5 J is about 15m more range @0.45g and that's not really worth the wear and tear and costs on the field IMO.
 

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After playing for some time, a person will be able to judge the range that the enemy can shoot and so therefore they will be able to keep outside of this. So this is when that 15 meters becomes vital.
Also, if you have the correct setup, using a big spring will not wear the rifle out very fast. I am still on the same trigger and piston system from about 8 years ago. The only part that I have gone through is the cylinder. I have gone through about 3 of these. But you also have to remember that I have also had my rifles up to 4.5 joules at some stages. (This was before we measured in joules)
 
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