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AEG not shooting at high enough fps

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Old June 8th, 2010, 13:49   #1
sushicake
 
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AEG not shooting at high enough fps

Having an issue right now with my AEG for some strange reason it wont fire properly with the madbull ultimate hop-up, bb's just kinda spit out and have barely any FPS. But when I swap in my old plastic CA hopup it shoots wonderfully at 370fps.

I checked the madbull and see nothing wrong with it so what could it be, the rubber is still intact with no rips or damage. My guess it's a loading nozzle problem, but working with one hop-up and not the other?

I might add that everything was shooting fine and dandy when I had my old stock CA gearbox shell this issue only started happening when I replaced it with the Modify Torus gearbox.

And if you were wondering the hop up was turned up a bit to ensure a seal.
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Last edited by sushicake; June 8th, 2010 at 13:53..
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Old June 8th, 2010, 14:13   #2
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sushi,
the Mad bull hopup require a different hop up rubber, try using a different rubber
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Old June 8th, 2010, 14:18   #3
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Quote:
Originally Posted by wildcard View Post
sushi,
the Mad bull hopup require a different hop up rubber, try using a different rubber
Tryed it with both madbull blue and the stock CA one both dont give me any fps. And like I said it only started happening after I replaced the gearbox cause the old one exploded.
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Old June 8th, 2010, 15:10   #4
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Quote:
Originally Posted by sushicake View Post
Tryed it with both madbull blue and the stock CA one both dont give me any fps. And like I said it only started happening after I replaced the gearbox cause the old one exploded.
try comparing the box, some of teh mechbox are a bit different in size and lenght the difference may not be much but it's enough to cause some drastic changes ie. Systema box is like a cunt hair smaller than KA when i swapped teh box on my KA Troy it was misfeeding like a bastard (it was fixed with hockey tape shims to make it perfect fit) or the difference in nozzle lenght can also have the effect that you have.
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Old June 8th, 2010, 15:23   #5
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sushi, I too had this issue. for some reason I could not shoot BBB .25's. BB's would fall and drop to the ground 20-30 feet out.

as soon as I used .28's, they sailed far. now that I've had time to break in the new MB rubber (4000ish rounds), I was able to go back to .25's. don't know why but suddenly they worked.

CA metal shell, G&P m120, MB ultimate tracer, MB rubber, SCS, MB 509mm tight bore barrel.
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Old June 8th, 2010, 15:57   #6
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Originally Posted by coachster View Post
sushi, I too had this issue. for some reason I could not shoot BBB .25's. BB's would fall and drop to the ground 20-30 feet out.

as soon as I used .28's, they sailed far. now that I've had time to break in the new MB rubber (4000ish rounds), I was able to go back to .25's. don't know why but suddenly they worked.

CA metal shell, G&P m120, MB ultimate tracer, MB rubber, SCS, MB 509mm tight bore barrel.
But my problem is that it wont even go 20 feet it'll go like a foot then drop... I'm guessing it's the unit itself something maybe misshapen cause it works with the old style one piece hopup but not madbulls "redesigned" one.

I'll look into it some more thanks for the help though.
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Old June 8th, 2010, 16:12   #7
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Likely your stock nozzle isn't meshing properly with the new hop up unit. It happens sometimes and sounds like the case here, you have such a bad air leak that you get the same velocity as a fart-propelled BB out of your ass. I am not familiar with that hop up unit, so I can't say what type of nozzle to get, but at least I opened the door for more discussion with that suggestion.
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Old June 8th, 2010, 17:05   #8
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Quote:
Originally Posted by CDN_Stalker View Post
Likely your stock nozzle isn't meshing properly with the new hop up unit. It happens sometimes and sounds like the case here, you have such a bad air leak that you get the same velocity as a fart-propelled BB out of your ass. I am not familiar with that hop up unit, so I can't say what type of nozzle to get, but at least I opened the door for more discussion with that suggestion.
Before my gearbox cracked and exploded it was shooting fine, but after replacing the shell (internals still all the same) it started not shooting properly. I might add that I was using the MB hopup before the gearbox cracked.

probably a shell fitment issue
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Old June 8th, 2010, 22:43   #9
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What brand of shell? I know there are tappet/nozzle/Deep Fire shell issues I've experienced in the past, and DF tappet plate in CA shells, nozzle doesn't go far enough forward to make a seal due to thickness issues.
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Old June 9th, 2010, 11:53   #10
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Quote:
Originally Posted by CDN_Stalker View Post
What brand of shell? I know there are tappet/nozzle/Deep Fire shell issues I've experienced in the past, and DF tappet plate in CA shells, nozzle doesn't go far enough forward to make a seal due to thickness issues.
Using the modify torus with the provided tappet plate. The tappet plate being the only internal piece being replaced.

Now that you mention it it could possibly be the tappet plate, or even a nozzle problem.

But the good news is is that it shoots about 360 now, must have worn in the hopup. But the speed fluctuates and insane amount. It can go from 299-389 anything I can do to make it more consistent?
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Old June 9th, 2010, 12:01   #11
hadur
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Make sure the madbull hop up unit is moving freely, sand down the clip if need be. I had this same issue and That seems to have been the issue
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Old June 9th, 2010, 12:03   #12
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what's happening here is not the nozzle not being able to fully reach the rubber, but not have enough power to fully push the BB in and mate the hop up rubber.

You mention changing the hop up unit helps, this pretty much nails it down.

the cylindrical space inside the hop up unit where the nozzle travels to push down the BB is where the problem is happening. The nozzle is rubbing strongly against the surface, and therefore slowing it down, and thus not being able to fully insert the BB into the hop up rubber(and mating the hop up rubber) before the spring shoots forward.

causes are usually:

-Tight travel space inside the hop up unit
-Hop up unit is inserted into the gearbox at an angle
-nozzle is generally too fat

If these are not the problem, the cause is strictly "too much resistance against the nozzle", so that should help you solve the problem.

so the first thing I'd try is sand down the nozzle a bit and make it thinner. Next is dremel the cylindrical space a little larger. Next is try to align the hop up unit to the gearbox properly.
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Old June 10th, 2010, 03:48   #13
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Get the soft type bucking for m120 and under and hard type bucking for m130 and over. Hope this can help you out and also check if you have a good air seal. I usually apply some piston lubricant inside the cylinder, cylinder head and the piston head itself.

Last edited by cjboi; June 10th, 2010 at 03:51..
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