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Narancas

Low FPS, same problem, different AEG.

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Long story short:

I had a m4 pdw (dboys or matrix brand) that I installed an m115 spring and 363mm tightbore barrel (madbull python) and got 365 fps out of it.

So today I installed an m120 (Magic box) and I got 280fps!!!!!!

( I have done all compression mods (teflon wrapped cyldiner head), nail polish mod, polished cylinder, new oring, new air nozzle w/ o-ring).

it seems version 2 gearboxes have beef with me since other gearboxes I work on come out great!....

Any thoughts on what it could be?

 

I used 10wt silicone oil in all my aeg cylinders and never had a compression problem.

The compression test is great but when I test it with the airnozzle w/ o-ring, air seems to escape passed the air nozzle's o=ring stilll....

 

 

Any help is appreciated.

thank!

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It's possie to be a miss marking or factory defect, I mean it happens.

 

Check over something's, sometimes things might crack when re assembling, you never know. Also check your bucking and hop up unit.

 

I once had a cylinder head have the front brass thing crack and only got 340 feet per second with an m140.

Edited by MrGearbox

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Update:

I assume im doing something wrong.

Today, I installed the m115 spring again and now im getting 308 fps.....(before it was 365 fps)...

 

update on what ive done so far:

im using a cylinder with no port

-363mm tight bore (6.03) madbull python ver.2

-m115 spring

(fps result :305-310 fps)

 

------------

When I installed the m120 (magic box brand)

I was getting 280 fps +/-

 

 

Im at the point of giving up with version 2 gearboxes :(

 

Notes:

as stated before, ive done all compression mods (even nail polish on nozzle to increase its diamter to reduce air leak in hop up unit).

But still I cant get good fps...

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Update 2:

seems its getting worse!

I re-installed the m120 spring and now im getting 280fps.

 

I cant think of anything else that might be causing this.

My only though is that there might be a massive airleak from air nozzle to hop up unit.

Ive used nail polish to increase its diameter but no luck..

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Trick I learned was to try a piece of paper over the bb pickup tube (Loosely). Load a bb into it first, holding the gun upside down, place the paper over the pickup tube. If you have a leak there, it'll puff the paper away.

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Update:

I finally got the hop up system (including barrel and all hop up unit components attached) at 100% compression.

 

When I test the cylinder with cylinder head. compression is 100%.

The only place that air is leaking from is the air nozzle. The air nozzle has an o-ring but air still seems to get through.

 

Anyone have some suggestions on how to seal air nozzle to cylinder head leak?

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evening update:

I assembled the aeg completely (I left the air nozzle leak dilemma alone for now) and when I shot it, it shows 360-365 fps with m115 spring).

Tomorrow morning, ill install the m120 and also shorten the new air nozzle since bb's can pass into the hop up since the nozzle doesnt retract all the way.

My only concern is it seems I have to shave about 2mm in order for bb's pass, im thinking its a little to much but will see!

Edited by Narancas

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evening update:

I assembled the aeg completely (I left the air nozzle leak dilemma alone for now) and when I shot it, it shows 360-365 fps with m115 spring).

Tomorrow morning, ill install the m120 and also shorten the new air nozzle since bb's can pass into the hop up since the nozzle doesnt retract all the way.

My only concern is it seems I have to shave about 2mm in order for bb's pass, im thinking its a little to much but will see!

When you shave it off make sure it is perfectly even.

 

Trust me if it isn't even bad things happen.

Edited by MrGearbox

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update:

found nozzle problem (after cutting new nozzle :(

 

--I installed a new tappet plate but the it had a different curve for the gear delayer and caused the nozzle to be more forward.

so I re installed the original tappt plate and everythings back to normal. (interesting how both tappet plates are dimensionally the same but had different desings in the delayer hand!.)

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