New Toy, barrel question

[Maginus]

Hey there folks, did some searching but was unable to find answers either due to me sucking at keyword searches or being blind lol

Anyways I just got a new JG AU-4G (AUG w/ RAS) I was thinking of making it look like one of those phantom aug's I have seen pictures of or at least close to it. Then I thought well this presents a perfect time to put a longer inner barrel in it since I will have a mock silencer to cover it.

So my question is does anyone know for sure what the maximum inner barrel length is for this AEG without loosing any velocity (FPS) from the BB?

Here is the one I bought so you can reference it.
http://www.airsoftmegastore.com/420_FPS ... -0447a.htm

[vatican.ninja]

I do not know specifically about that stock gun, but I believe it depends more on the cylinder. This thread in the stickies addresses barrel length and the cylinder type. Hopefully you find the information helpful if you haven't run across it before.

http://airsoftpacific.com/viewtopic.php?t=31747

[Evil Zergling137]

I recommend

a) using a hotter spring to increase FPS
b) get as much air behind the bb as you can.

regarding his link, if you want to maximize FPS with a smaller spring it could be helpful. Mostly though you probably want 2 times as much air in the cylinder as barrel.

[Maginus]

Problem is when shopping online they don't tell me what the volume of the cylinders and barrels are just the length.

[Jester316]

You'll want an unported cylinder and a 510mm tight bore barrel (6.03mm or less).

And you don't need 400fps. At that speed, there is a lot of turbulence around the bb as it leaves the barrel and can screw up accuracy. I've built 3 guns under 300fps that have great accuracy, nearly the same range as stock 400fps guns, and has an increased ROF (not as difficult to pull back the spring means it can be pulled back more times in a minute).

[Maginus]

The store says it shoots 420 but it doesn't it is 330 to 360fps so they musta used a 0.12 bb to measure that at 420

[Osprey]

The store says it shoots 420 but it doesn't it is 330 to 360fps so they musta used a 0.12 bb to measure that at 420

.12 No one use those. I don't know way manufacture or websites measure the FPS using .12.

[Variable]

There are websites that just plain exaggerate the FPS claims. Jungletoy, AA and Shorty used to. The guns at wal mart and big 5 often say "400fps!*" *measured with .12g BB.

[Jester316]

The store says it shoots 420 but it doesn't it is 330 to 360fps so they musta used a 0.12 bb to measure that at 420

.12 No one use those. I don't know way manufacture or websites measure the FPS using .12.

Because people think that having a higher fps makes their gun better, when in fact it helps wear it down quicker. By measuring with .12's, they are not lying when they say it shoots 420fps. However, they know that no one will use .12's. If they put the measurement with .2's then people would be less likely to buy it because of FPS.

[Evil Zergling137]

You'll want an unported cylinder and a 510mm tight bore barrel (6.03mm or less).

And you don't need 400fps. At that speed, there is a lot of turbulence around the bb as it leaves the barrel and can screw up accuracy.

Do like he says. 330fps is a good velocity. I would recommend increasing your bb weight until it is under that. Much less air resistance.

But (unlike what he says) for ROF I would use better parts - not a lower spring. High .2g FPS, heavy bbs and high ROF make the trifecta for an effective airsoft weapon.

a) powerful string for fps (~410fps with .2g)
b) heavy bb for accuracy (.28g+ bb)
c) better internals for ROF (18+)

[Jester316]

You'll want an unported cylinder and a 510mm tight bore barrel (6.03mm or less).

And you don't need 400fps. At that speed, there is a lot of turbulence around the bb as it leaves the barrel and can screw up accuracy.

Do like he says. 330fps is a good velocity. I would recommend increasing your bb weight until it is under that. Much less air resistance.

But (unlike what he says) for ROF I would use better parts - not a lower spring. High .2g FPS, heavy bbs and high ROF make the trifecta for an effective airsoft weapon.

a) powerful string for fps (~410fps with .2g)
b) heavy bb for accuracy (.28g+ bb)
c) better internals for ROF (18+)

Using heavier bb's to reduce FPS does not affect the overall energy (and is against the rules for chronoing). Shooting 400fps with .2's is shooting 357fps with .25's (338fps with .28, 326fps with .30's) is still shooting 1.48 Joules of energy. While yes, a heavier bb will be more accurate, it is still subject to the turbulence coming out the front of the barrel.

Put in a lower spring that makes it shoot 330fps with .20g bb. My last 2 guns both shot 275fps with .2's, and I have no issues with getting kills. I range further then a lot of 400fps guns, I get higher ROF, and my gearbox will last longer due to the reduced spring pressure in the gearbox (how ever utilizing the 11.1v lipo I use means I get more functional wear on the gearbox).