Kings arms SIG556 low power?

[LazzurusMan]

So I picked up a King Arms SIG556 HOLO EBB from my local airsoft shop yesterday and they said it was only firing around 280 fps, when everything I've read online says it should be 300-350 straight out of the box. It is an ex display model and was heavily discounted from the usual retail price.

Anyone got any suggestions of how to get it as close to 350 as possible?

[Monty]

The problem could be airloss within the gearbox or hop up, or the spring could just be weak. Some suggestions;

 

Try the floss mod / teflon taping the hop up unit as that'll keep the air from escaping between the inner barrel and hip up unit.

 

Replace the bucking with a higher quality bucking such as a Guarder clear or Maple leaf, etc. Replacing the inner barrel with a quality tightbore barrel will also up the FPS significantly.

 

Now for the complicated stuff, involves opening up the gearbox;

 

Teflon tape the stock cylinder head / stretch out the o-ring by placing it over the cylinder and heating it up with a lighter.

 

Replace the nozzle for one with a o-ring inside of it.

 

Change the piston head for one with x2 o-rings, or repeat the same steps for the cylinder head o-ring to the piston head o-ring.

 

AOE correct the gearbox, plenty of info on here about it

 

And use quality BB's, better consistency overall, accuracy and FPS wise. Don't bother replacing the spring until you definitely know there isn't an airleak.

 

Hope that helps

[LazzurusMan]

I've changed the barrel for a 6.01mm tightbore and added a Guarder hop bucking, that's brought me up to 300fps. Any tutorials or guide anyone can link me to about everything else Monty told me to do?

[LazzurusMan]

And seeing as I'm doing stuff with my hop anyway, does anyone have any opinions on G-hop? Is it worth it? The bucking that came on the gun was ruined, so I might be able to use that for a G-hop if I can cut off a large enough piece that isn't ruined for a contact patch.