Classic Army M15A4 CQB

smallbike

Hi Folks,

I'm wondering if anyone has had a similar problem to mine.
I got the above mentioned aeg a couple of years back and it is still my primary rifle. when i got it it was firing about 260fps out of the box. Not being entirely satisfied, i popped out the spring and replaced it with a stronger one which brought it up to about 280fps. At the time i said," ah sure, it'll do".

as time went on it got a little frustrating as the bbs weren't quite reaching their target when everyone else' were, so...

I put in a new tight bore barrel hoping that might help and while it did help with accuracy slightly, the fps remained the same.

I mentioned the fps issue to the guys in airsofteire and they said they had someone in before who had the same issue with this rifle.

I had had my eye on a systema turbo set for a while, so i figured I'd get one, pop it in and see what happens. the answer was nothing. the box and motor worked fine, but there was no fps change. i opened the box. took out the spring. got a new one, again. closed the box. nothing.

At this stage I've opened both boxes, had a look around and cant see anything that could be causing the low velocity. I'm still using the same hop up unit that came with the rifle although the rubber has been changed a few times.

Any ideas on what i can do to bring it above the 300fps mark? could there be air leaking from the hop up unit somewhere? It might be a stupid question but i really can't think of anything else.

I read somewhere once that if you're using a short barrel, the bb may have left the barrel before the piston has fully decompressed so i changed the barrel to the longer, standard m4 one, also a tight bore.

If anyone has any ideas it would be greatly appreciated!

If not, sure it'll just have to do!

Steve

Rooky1

Hey

Did you check the compression in your Cylinder?

Take the cylinder out with the cylinder head and piston still in it.
Put your finger over the outlet tube in the cylinder head and slide the piston in and out.

You should feel a good bit of resistance.
If the piston is moving in and out with virtually no resistance then your piston head oring could very well be worn out (or just a very bad fit).

Replace with a new oring and see if that makes any difference.

You can pick orings up at any good hardware store or motor factors.

smallbike

cheers rooky, will do!:)

Rooky1

smallbike wrote: »

cheers rooky, will do!:)

No bother.
I hope it helps.

JonnyTwoCombs

Couple of things you can do.

As Rooky said, check the compression / air seal.

Take the cylinder head out of the cylinder and give it a little silicon oil around the O ring. Then wrap PTFE tape around the O ring to increase air seal.

Clean out the cylinder and swear a small bit of litium grease on the inside and replace the cylinder head.

You could also swap out the spring.

glicster

have you checked the sorbo pad on the cylinder head? happened me before and the last thing i looked at was the cylinder head and noticed that the sorbo pad(black cushion where the piston hits the cylinder head) was frayed,thus letting some compressed air leak out very easliy. one morwe thing is to remove the piston head o ring and stretch it a bit and then replace it.might help?

smallbike

serious thanks for the tips guys.
although i haven't reopened the box yet, i will be doing so this week. just finishing off respraying everything before i do anything else.

ill probably be back for more info when the whole thing goes bottom up!

thanks again!