[1tonne]

Great write-up (I have not read all of it yet but from what I see it looks good).
One thing I did note is that you say that the PDI hopups are good. I don't know if you have ever owned one but they are not that great. I have owned 2 of them and I got rid of them both. I now recommend that people don't waste their money on one.
They are hard to make accurate (they can be made accurate though) and they also loose FPS because they use AEG buckings. If they stuck with normal VSR or L96 buckings (These designs are better than the AEG bucking design) then the hopup chamber would have been better than a standard chamber.
I would suggest you edit that part out. Cheers

Also people can use an extra long barrel to make their gun more accurate but it will need a little downward curve (from a long range barrel mod) to make the bb travel along the top of the inner barrel. This will mean the bb will exit the barrel at the same point each time. So you can get excellent accuracy and more FPS with a long inner barrel but you will need the LRB mod.

Another thing is I found the Reaps bucking to be good but the Maple bucking is better. The nub is designed slightly better.

One thing I wonder about barrels with rifling is, how do you clean them? I would think that you would leave little pieces of cloth in the rifling.

 

[1tonne]

This does go into dangerous ground and the more it is talked about the more people are likely to abuse it. It is best that it is not talked about too much. In short it does work.

 

[1tonne]

It is dangerous because a lot of clubs insist on chronoing with 0.2gm bb's (your club may not but others do) and then let people use whatever bb weight after that. This means people can get around the safety measures put in place.
I once made a rifle fire 550fps but the energy behind the bb was a lot more than just a 550fps. (It was ridiculous). I never gamed it though as it would have put a hole in someone.
Talking about this just helps people to learn more about JC and want to experiment with it.

 

[1tonne]

And why would they ever change that, if they don't know about JC?
Or is there another reason, that they want to hold on to the old ways?

I agree. Lack of knowledge is dangerous but it would be better to go directly to the people who run the clubs to tell them instead of telling everyone how to JC before the clubs have change their rules.
I know by reading other threads on here that some clubs are just stuck in their ways (for one reason or another) and so it is best to not speak of it JC until people who run the clubs have better understanding and change the rules.
That is my thoughts anyway. If you wish to carry on talking about it, then feel free.

 

[1tonne]

Thanks for that. We know that we cannot stop it but it is just safer not to talk about it.
First rule of fight club; don't talk about joule creep :hehe:

 

[1tonne]

I got a question. If you make your piston shorter you should get more cylinder volume - at least my theory. If someone with the will and funds is trying to test that we could end the rule of the VSRs

Already been working on that. I am in the process of making a piston head that is only about 5mm thick for a DMR.

 

[1tonne]

How short will the piston go?

 

[1tonne]

Hi Sumta

This is a good write up but not all the info is correct or has not been proven.
The two questions that most people wonder about with barrels are, "what is the best length barrel?" and "is wider bore better than tight bore?" These two points in your thread I believe have been answered wrong.

For example:
It says tight bore is not good for long range. There is no proof to say if tight bore is better or wide bore is better. People have only surmised that wide is better but this is only guess work. The only real proof we have is that all the longest shots on this forum were made with 5.98mm tight bore inner barrels.

Also, the thread recommends a 455mm long barrel as best. This does not take into account bb weight or the cylinder volume. Different bb weights need different compression ratios to get the most efficiency. I know that for the VSR10 these are the best barrel lengths to get the most efficiency:

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

So there is no fixed best barrel length. It depends on your cylinder size, bb weight and also barrel diameter (can create too much waist air).

These points need to be corrected as they are very important points.
If they are not corrected, then I would suggest the thread is unstickied as these are some of the most important points when choosing a barrel and people believe the thread to be gospel.

I would rather your thread stay stickied as a lot of the other info is good. It just needs altering a little

One other thing in the thread is that you mention barrel suck. This does happen in spring rifles like the VSR10 but not in AEG's as the air nozzle retracts and lets in air behind the bb. So in some circumstances it is correct but not always. But this point is not as important as the 2 previous points I mentioned.

 

[1tonne]

I'm using a 715mm ZCI SS 6.02 in my Real Sword SVD and it's pretty consistent on hitting a chimney-stack over 300ft away with AGL 0.4g BBs.

An AEG has a different setup to most sniper rifles and so they can take longer barrels although the longer barrels still are not optimal. You should try a 250mm inner barrel and see how that goes.

 

[1tonne]

I think a 250mm inner barrel would work quite well. Did you try it?

I use short barrels and they work a treat.