ICS Sig advice.

[zetec]

Need a little advice on our ICS Sig 552 MRS, new gun used a couple of times. Firstly FPS seems a little low at about 250, but has decent range so not too bothered by this. What I do find strange is that the piston only returns to fully extended every other time it is fired on semi auto. I always dry fire when finishing a game to make sure the spring is not compressed, but noticed the other day that I could see the piston in the cylinder port so it was mid way in its travel, fire the gun once and it stops in the fully extended position, fire again and stops mid point again...and so on. I now suspect that this could be the possible reason for a low FPS reading as the spring could have spent a lot of the time partly compressed.

Is this normal? And is it worth fitting a new spring?

Any advice most welcome.

 

[Airsoft-Ed]

It's to do with how the cut off lever is set up. My L85's the same.

I actually helps act as a sort of pre-cocking mechanism to aid with faster trigger response. I've never been sure whether they were designed with that in mind, or if it's something that happens when it shouldn't, but I've never really noticed it cause anything bad.

There's no reason why it'd alter the fps as the piston is still released from the same point each time.

As for the 250fps, I've been seeing similar issues with two different ICS L86s, I think it's down to a fault line somewhere between the hop unit and the gearbox, I dunno if a whole batch of various guns might've been made with defective hop units or something, but it seems weird that I've had it happen to two different L86s in the space of about a month, and then you have a similar sounding issue with a Sig...

It's probably a pipe dream I'm having but it's a weird coincidence. I'd just try sticking a stronger spring in it. Maybe go for an M110 or something.