Upgrade Help.

[Shenaf]

I need some help. I have just put a new air nozzle with an o ring and a 6.03 barrel on my g&g, I was previously getting 285 FPS on .25s I am not down by 100 FPS. I have done the paper test and it didn’t move so I know I am getting a good air seal. The barrel is around 100mm longer than the standard, due to my stupid mis calculation. Could it be the barrel length that has took 100 FPS off me? 

 

[Iceni]

new air nozzle

Did you measure the original and the new one to make sure the lengths were the same.

Did you install the air nozzle over the tappet plate correctly - Is it moving correctly with every shot.

Did you damage the piston O-ring when you took the gearbox apart - Is the o-ring free to move in the piston head - Is it lubricated.

To get such a significant drop in FPS there is a big mistake somewhere on that gearbox. Start with the basic stuff, A hand compression test of the Cylinder and components, and a visual inspection of the air nozzle and it's fittings. The chances of it been just the barrel are slim - Typically a badly installed barrel would be showing you an airleak and giving misfeeds/no-feeds. Adding length should have actually increased the FPS slightly if installed correctly.

 

 

[Shenaf]

I think it could be the nozzle. I didn’t measure the old one I just went off advise. I’m going to swap the old nozzle back in and check FPS again. 

 

[Rogerborg]

I have done the paper test and it didn’t move so I know I am getting a good air seal.

Paper over the feed tube to check that air isn't blowing out that way?  Good idea, and a surprising result - I would have expected any new problems to be from the nozzle being a different length and not sealing.

That also (probably) rules out the hop unit not being pushed back against the gearbox because of a missing tension spring.  And unless there's something seriously wrong with that barrel, it's unlikely to be there.

So, yes, I'd go backwards.

It is easy to not have the nozzle connected to the tappet plate, we've all done it (once) so that's definitely worth checking. Then you're back into the gearbox looking for air seal.  Did you do anything while you were in there?  Lube or wrap the cylinder head?  Lube or stretch the piston O-ring?

Check that the piston is square on its runners, and that any cut out winder on the cylinder is towards the rear end.

You'll get it, you'll just need to be methodical.

 

[Shenaf]

FIXED. 
 

changed back to the old nozzle and measures the new nozzle was ever so slightly bigger so obviously pushed the bb forwards before letting the air go. Hence why the paper test didn’t show. My guess being the bb was already half way down the barrel before the air hit it. Now I need to buy a correct nozzle. But for now I’m back to 285fps on .25s.

 

[Rogerborg]

Huh, that's peculiar. With a longer nozzle, you'd usually get feed issues.  Was the new nozzle properly connected to the tappet plate?

That said, it's airsoft, so there's always a new way for things to go wrong.

 

[Shenaf]

The nozzle was attached to the tappet plate. I did start getting feeding issues but I was like a mid feed for every 20 shots. Not being on a field I found that out by trying to figure out if the chrono was broke.