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Methos · April 2nd, 2009, 19:08

First off I'll say hello: "Hello!"

I am a frequent reader of these forums, but a rare poster as that handy search button normally provides all the answers I need, but this one truly has me stumped.

I got my first airsoft gun - a G&G M14 - about a year ago now and it has gone from stock to this:

EXTREME-FIRE SW MOSFET Computer.
Systema Magnum Motor (Short type)
Prometheus EG Hard gear set (Helical) & Reinforced piston (full tooth)
G&G M14 Upgrade Cylinder (type-0 / no ports) , Cylinder Head & Piston head kit for M14
Airsoft Surgeon stage 4 spring
Stock 6.04mm Barrel
Prometheus Hard (red) Hop sleeve
H-Hop bucking (black)

Now, that setup shot at 530FPS with .2's and could hit a man sized target at 200 yards - I also did all the upgrading myself. I finally decided to spend that last £50 and get an upgraded barrel, and after some research set for a madbull v.2 509mm (for M16 / AUG). The reason being that the G&G stock barrel is 517mm long and it uses an AUG hopup, same as an AUG (duh) and M16 variants.

The barrel arrived in the post today and I choro'd my gun before I put it in, the expected 530 came out on reader. I took it apart, put in the madbull 6.03 tightbore and chrono'd again.... 450FPS with a .2 ... eh?

So, I cleaned the barrel for factory impurities... still 450.
Did the "BB roll" test to see if the barrel was mis-shaped somehow - flawless performance.
So I took it apart again, this time down to the gearbox to check if I was losing compressing anywhere - but all seemed fine in there, even checked the airseal nossel but nothing seemed wrong.
Swapped out the Prometheus (hard) sleeve for a stock (softer) one - as the hard one has caused trouble previously.... 450
Swapped the hop unit (which is a nicely constructed metal one) for another one I had around. .... 450 still
Removed the hop bucking completely just in case it was protruding an abnormal amount into the barrel (though a quick eye inspection down the barrel usually identifies this I thought it couldn't hurt).... 450

Despite all of the above the FPS didn't change a bit

I was aware of the infamous "vacuum" problem that some people experience, but from some reading I have done around this site and others, it doesn't appear that it could be that either. Correct me if I'm wrong (and the answer is still relevant) but the "vacuum" only occurs when your cylinder can't compress enough air for your barrel? Seeing as this barrel is a) shorter and b) tighter than my stock one I can't see that being the case.

Any genius' feel like cracking this nut?

Feedback would be wickedly appreciated!

Methos.

April 2nd, 2009, 19:08	#1
Methos Trader rating Join Date: Jul 2008 Location: England	G&G M14 Upgrades. First off I'll say hello: "Hello!" I am a frequent reader of these forums, but a rare poster as that handy search button normally provides all the answers I need, but this one truly has me stumped. I got my first airsoft gun - a G&G M14 - about a year ago now and it has gone from stock to this: EXTREME-FIRE SW MOSFET Computer. Systema Magnum Motor (Short type) Prometheus EG Hard gear set (Helical) & Reinforced piston (full tooth) G&G M14 Upgrade Cylinder (type-0 / no ports) , Cylinder Head & Piston head kit for M14 Airsoft Surgeon stage 4 spring Stock 6.04mm Barrel Prometheus Hard (red) Hop sleeve H-Hop bucking (black) Now, that setup shot at 530FPS with .2's and could hit a man sized target at 200 yards - I also did all the upgrading myself. I finally decided to spend that last £50 and get an upgraded barrel, and after some research set for a madbull v.2 509mm (for M16 / AUG). The reason being that the G&G stock barrel is 517mm long and it uses an AUG hopup, same as an AUG (duh) and M16 variants. The barrel arrived in the post today and I choro'd my gun before I put it in, the expected 530 came out on reader. I took it apart, put in the madbull 6.03 tightbore and chrono'd again.... 450FPS with a .2 ... eh? So, I cleaned the barrel for factory impurities... still 450. Did the "BB roll" test to see if the barrel was mis-shaped somehow - flawless performance. So I took it apart again, this time down to the gearbox to check if I was losing compressing anywhere - but all seemed fine in there, even checked the airseal nossel but nothing seemed wrong. Swapped out the Prometheus (hard) sleeve for a stock (softer) one - as the hard one has caused trouble previously.... 450 Swapped the hop unit (which is a nicely constructed metal one) for another one I had around. .... 450 still Removed the hop bucking completely just in case it was protruding an abnormal amount into the barrel (though a quick eye inspection down the barrel usually identifies this I thought it couldn't hurt).... 450 Despite all of the above the FPS didn't change a bit I was aware of the infamous "vacuum" problem that some people experience, but from some reading I have done around this site and others, it doesn't appear that it could be that either. Correct me if I'm wrong (and the answer is still relevant) but the "vacuum" only occurs when your cylinder can't compress enough air for your barrel? Seeing as this barrel is a) shorter and b) tighter than my stock one I can't see that being the case. Any genius' feel like cracking this nut? Feedback would be wickedly appreciated! Methos.