Upgraded CA trouble

[incrediboy729]

I have a classic army m15a4 and here are all the parts i have installed (with an x for recently installed within the week):
G&P m160 motor x
12v elite mini wired to deans (was a 10.8v but i added a cell for extra power x)
Guarder m140 spring x
G&G Hyper torque helical gears x
Systema hopup bucking x
CA tightbore
So after all these are installed everything is fine and dandy with very high fps. After shooting it more the velocity goes down to the point where i cannot pierce the bottom of a soda can first shot 2 inches away. Shooting from a distance (20-25 yards) will either get me through one side or none. With a m140 i would assume my fps would be a bit more no? Is there something wrong? i have checked the internals since the fps loss and everything is fine, cylinder compression seems good. What do you guys think? piston head maybe? Much thanks in advance.
-Brett

[Styrak]

So it started losing FPS? Strange. Did you make sure to lube the piston head/cylinder?

[incrediboy729]

i heard mixed feelings about lubing the piston head......but i put some white lithium on the inside of the cylinder. so you think that's a little low fps for an m140 too?

[Styrak]

Well....an M140 should be pushing 450fps+, so if it can't pierce the bottom of a can then yes, it's VERY low for that spring.

[kalnaren]

Get rid of the CA tightbore. I guarantee you that's your problem. They're pieces of shit. I don't know what they coat them with, but it causes ridiculous amounts of friction. The barrels literally shred BB's.

I was talking to one of the former ASCA guys about it, and he said when they had them they cut one in half lengthwise to see what the problem was and could literally peel stips of plastic off the inside of the barrel. I had one in my G36 and man, it was crap.

[incrediboy729]

Originally Posted by kalnaren

Get rid of the CA tightbore. I guarantee you that's your problem. They're pieces of shit. I don't know what they coat them with, but it causes ridiculous amounts of friction. The barrels literally shred BB's.

I was talking to one of the former ASCA guys about it, and he said when they had them they cut one in half lengthwise to see what the problem was and could literally peel stips of plastic off the inside of the barrel. I had one in my G36 and man, it was crap.

Greaaaaat.........spent $40 for nothing......well thank you very much though, i will put my stock barrel in and see where that gets me. And i can pierce through the bottom of a soda can, but not first try. i have to hit the exact same spot AGAIN and then it will usually pierce. But even that seems low.
Thanks everyone for the quick responses, i will get back to you when i've put my stock barrel back in.

[Amos]

Get a real chrono!

That'll really help with your builds

I'd reccomend the Xcortech 3200, It's cheap and VERY accurate.

[incrediboy729]

Well i installed my stock barrel back and still pretty much the same result, both visibly and with the can. Btw tho i had my tightbore custom cut, and i have the rest of the section that was cut off and neither ends have the plastic you speak of. Maybe they fixed this in the newer versions?
hahaha, well i would like to have one but i don't have the money right now, thank you though. i am going to my local store to have it chronoed asap.
so what other things do you think i could be? i'm really stumped here....compression *seems* good so that rules out piston/cylinder assembly (right??), barrel ass. compression seem good (covering both holes in the hopup assem. and blowing into the barrel gives zero leakage).

[kalnaren]

Hmm, the barrel really would have been my guess. Oh well, sorry to make you go through the effort.

Is the spring in the right way? And, check the spring in another gun. I have a Promethius M110 that was shooting at 240.

[incrediboy729]

Originally Posted by kalnaren

Hmm, the barrel really would have been my guess. Oh well, sorry to make you go through the effort.

Is the spring in the right way? And, check the spring in another gun. I have a Promethius M110 that was shooting at 240.

No problem. Anything helps.

The spring is in the right way yes, tighter coils on the spring guide. Boy that thing sure was hard to wrestle into the gearbox. Sorry but i can't do that, i have no friends that have a gun capable of pulling an m140.
Everything sounds very smooth when firing, no grinding or squealing.

[incrediboy729]

Well i called the place i bought it from to see what they said and they said that even if i checked compression, i couldn't create the pressures of a airsoft spring, and that it was probably a compression problem in the cylinder head or nozzle (i was suspecting that also). What do you guys think? When i get the money i will probably get the systema silent piston head set. They also said to put in my stock spring back in and see if i still have low fps.
Does everyone agree with this?

[Amos]

Replace the piston head / cylinder head / cylinder with quality parts.

Get some Prometheus parts... If you cheap out on lower quality parts on such an extreme build you will not get the results / reliability that you're hoping for.

[incrediboy729]

Isn't systema quality? And does Prometheus make a silent piston head?
Thanks for the quick response

[Donster]

Originally Posted by incrediboy729

Isn't systema quality? And does Prometheus make a silent piston head?
Thanks for the quick response

systema parts are overrated IMHO. Prometheus doesn't make a silent piston head, but you can just buy some sorbo for that.

[Amos]

Originally Posted by incrediboy729

Isn't systema quality? And does Prometheus make a silent piston head?
Thanks for the quick response

Systema is quality... but the parts are over-rated and beginning to be out-dated by newly designed stuff.

Right now from my experiences Prometheus is Top Dog

Their Neo Strike line is AMAZING.