Spring compressed?

Petro · September 30th, 2013, 21:28

Hi guys,

So I started fiddling around with my new G&P (well, new to me but the other guy only had it about a month). Some of you may have read my other thread where I thought it might be shooting low as I was getting about 310 fps using .25's. I watched some youtube videos on disassembling your gun and I thing I may have found an issue.

At the end of each game, I always make sure once I've removed the mag, to fire a couple shots on semi to make sure the chamber is cleared of bb's. On the dis-assembly videos I saw the guys being able to push on the air nozzle while it's attached to the gear box and it moves forwards and back. Mine doesn't. It's in the full back position. Would this essentially be storing the gun with the spring compressed or is this normal? Obviously if it is storing the gun compressed, my spring is probably been weakened and thus the low fps.

K3vX · September 30th, 2013, 21:37

1.12J (347fps using 0.20 BB) is not that low, and can happen for a number of reason, the last of them being a weakened spring due to compression.

It could be due to a air leak at the piston to cylinder, at the cylinder to cylinder head, at the cylinder head to nozzle, at the nozzle to the hop-up unit.

Also, compressing a good spring for some amount of time in general will not deteriorate it in anyway (assuming it's already "broken in"), and a bad spring doesn't need constant compression to lose it's strength.

Petro · September 30th, 2013, 21:39

OK, but when you're storing the gun or the gun is "off", battery out, etc., should the nozzle be all the way forward, back or it doesn't matter?

K3vX · September 30th, 2013, 21:44

Quote:

Originally Posted by Petro

OK, but when you're storing the gun or the gun is "off", battery out, etc., should the nozzle be all the way forward, back or it doesn't matter?

The nozzle is all the way forward when the cycle is either 1)Not started, meaning no compression or 2)Near end, when the rifle is a few teeth away from firing.

The nozzle will be pulled between those two times to "chamber" a round and return to the ready position to be fired.

Maybe you have what is called "over-spin" when even a single semi shot will turn the gear with such force that the momentum of the motor and gears will pull another half-cycle after the trigger is released. It is not impossible if you have a decent rate of fire in full-auto fire, and a "weak" spring. Hard to confirm through a forum.

Petro · September 30th, 2013, 21:52

Right, thanks. I'm guessing then something is wrong since the nozzle should be all the way forward. Trying to open up the gearbox to take a look but can't get the damn buffer tube off. Took the main screw out from the inside middle area, but it looks like there are 2 VERY small hex screws on the outside and I don't have a head small enough for them

ThunderCactus · September 30th, 2013, 22:02

Nothing is mechanically wrong with any springs in your gun.
Depending on the spring material, you can leave a gun with the spring fully compressed for over a year and not lose more than 5fps.

What's extremely likely is you lost seal somewhere. Either loss of compression in the cylinder, or the hopup has been damaged.
What's also somewhat common, is sometimes an idiot will forget they need to CLEAN the barrel, fire off 12000 rounds, complain of fps loss, and then I charge them $30 for having cleaned their barrel.

Petro · September 30th, 2013, 22:05

Thanks ThunderCactus, I don't know if they guy before me did or not, but after reading everything here that I have, I clean my barrel after every game. Will do an air seal test if I can every get the buffer tube of

Petro · October 1st, 2013, 00:18

Thanks again for all the help guys, learned alot tonight. Took apart my first gearbox for the first time and managed to get it all back together. Looks like it's a couple issues. The sector gear was, for lack of a better word, "misaligned" so the tappet plate was sitting normal, but had the air nozzle pulled back. Fixed that but I believe I have an issue with either the air nozzle, O-ring or both. While I had the gearbox open, I held my finger against the air nozzle, pushed it all the way back and tried to push the piston in. It went all the way in without any resistance whatsoever. The O-ring around the piston fit VERY loosely and was pretty much the same diameter as the piston itself.

ThunderCactus · October 1st, 2013, 02:56

The piston only compresses when it accelerates forward very quickly
And the only way the nozzle could be pulled back with the tappet being normal is if the tappet were broken and the air nozzle somehow jammed.
And everything is timed off one gear so nothing in the gear train can be misaligned.
Focus on the piston head, everything else is fine.

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September 30th, 2013, 21:28	#1
Petro Trader rating Join Date: Jul 2013	Spring compressed? Hi guys, So I started fiddling around with my new G&P (well, new to me but the other guy only had it about a month). Some of you may have read my other thread where I thought it might be shooting low as I was getting about 310 fps using .25's. I watched some youtube videos on disassembling your gun and I thing I may have found an issue. At the end of each game, I always make sure once I've removed the mag, to fire a couple shots on semi to make sure the chamber is cleared of bb's. On the dis-assembly videos I saw the guys being able to push on the air nozzle while it's attached to the gear box and it moves forwards and back. Mine doesn't. It's in the full back position. Would this essentially be storing the gun with the spring compressed or is this normal? Obviously if it is storing the gun compressed, my spring is probably been weakened and thus the low fps.

September 30th, 2013, 21:37	#2
K3vX Trader rating Join Date: May 2012 Location: Quebec City	1.12J (347fps using 0.20 BB) is not that low, and can happen for a number of reason, the last of them being a weakened spring due to compression. It could be due to a air leak at the piston to cylinder, at the cylinder to cylinder head, at the cylinder head to nozzle, at the nozzle to the hop-up unit. Also, compressing a good spring for some amount of time in general will not deteriorate it in anyway (assuming it's already "broken in"), and a bad spring doesn't need constant compression to lose it's strength.

September 30th, 2013, 21:39	#3
Petro Trader rating Join Date: Jul 2013	OK, but when you're storing the gun or the gun is "off", battery out, etc., should the nozzle be all the way forward, back or it doesn't matter?

September 30th, 2013, 21:52	#5
Petro Trader rating Join Date: Jul 2013	Right, thanks. I'm guessing then something is wrong since the nozzle should be all the way forward. Trying to open up the gearbox to take a look but can't get the damn buffer tube off. Took the main screw out from the inside middle area, but it looks like there are 2 VERY small hex screws on the outside and I don't have a head small enough for them

September 30th, 2013, 22:02	#6
ThunderCactus Not Eye Safe, Pretty Boy Maximus on the field take his picture! Trader rating Join Date: Feb 2007	Nothing is mechanically wrong with any springs in your gun. Depending on the spring material, you can leave a gun with the spring fully compressed for over a year and not lose more than 5fps. What's extremely likely is you lost seal somewhere. Either loss of compression in the cylinder, or the hopup has been damaged. What's also somewhat common, is sometimes an idiot will forget they need to CLEAN the barrel, fire off 12000 rounds, complain of fps loss, and then I charge them $30 for having cleaned their barrel.

September 30th, 2013, 22:05	#7
Petro Trader rating Join Date: Jul 2013	Thanks ThunderCactus, I don't know if they guy before me did or not, but after reading everything here that I have, I clean my barrel after every game. Will do an air seal test if I can every get the buffer tube of

October 1st, 2013, 00:18	#8
Petro Trader rating Join Date: Jul 2013	Thanks again for all the help guys, learned alot tonight. Took apart my first gearbox for the first time and managed to get it all back together. Looks like it's a couple issues. The sector gear was, for lack of a better word, "misaligned" so the tappet plate was sitting normal, but had the air nozzle pulled back. Fixed that but I believe I have an issue with either the air nozzle, O-ring or both. While I had the gearbox open, I held my finger against the air nozzle, pushed it all the way back and tried to push the piston in. It went all the way in without any resistance whatsoever. The O-ring around the piston fit VERY loosely and was pretty much the same diameter as the piston itself.

October 1st, 2013, 02:56	#9
ThunderCactus Not Eye Safe, Pretty Boy Maximus on the field take his picture! Trader rating Join Date: Feb 2007	The piston only compresses when it accelerates forward very quickly And the only way the nozzle could be pulled back with the tappet being normal is if the tappet were broken and the air nozzle somehow jammed. And everything is timed off one gear so nothing in the gear train can be misaligned. Focus on the piston head, everything else is fine.

Spring compressed?

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