G&G GR4 CQB-R 270fps?

[Noenine]

Hi, I wonder if anyone can help. I am fairly new to airsoft and bought myself a G&G GR4 CQB-R. It only shoots around 270fps sometimes lower and has done from the start. Is that kind of fps a problem? Should it be firing at a higher fps? If so what can I do to sort it out, I want to be able to do any of the work myself and don't mind giving it a go. I'd like to get around 330fps with 0.25s. Also if I extend the barrel from its current size (260mm) to a 360mm tightbore would I have to make any changes with any internals?

Thanks for the help!

[Orion1]

Re: G&G GR4 CQB-R 270fps?

It sounds like you have an airleak, have you changed or moved your hop-up rubber or barrel, if it is a new gun take it back and get a new one. You could take it to a tech to look at.

[jagillham]

Re: G&G GR4 CQB-R 270fps?

What is your site limit?

[Noenine]

Re: G&G GR4 CQB-R 270fps?

Unfortunately I have had it for a while, but just assumed the fps was normal but now know it should be 330ish with 0.2s. I have taken out the barrel and hop up but don't think I disturbed much. Also my hop up chamber hasn't got that little spring at the front of it. Not sure if it makes any difference at all!

[Noenine]

Re: G&G GR4 CQB-R 270fps?

330 I think.

[jagillham]

Re: G&G GR4 CQB-R 270fps?

That will be 330 with .2's.... so you'll want it more like 310 with .25's

[Noenine]

Re: G&G GR4 CQB-R 270fps?

Ah I see, yes, I'd like it to shoot roughly 310 with 0.25s

[Flanbix]

Re: G&G GR4 CQB-R 270fps?

I think it is normal that you don't have the spring on the hop unit (if it is the same as my CM16).
You have most probably a bad air seal. Perhaps at the piston head, cylinder head or noozle or the 3 at the same time...

[Flanbix]

Re: G&G GR4 CQB-R 270fps?

Server error...

[jonny lovegrove]

Re: G&G GR4 CQB-R 270fps?

My gr16 r5 was firing at 290 on .25s (have changed barrel, hop and motor since though) and i thought that 298fps on .25 was 330 on .2?
And it was getting around 50/60m on a bog standard setup

[dannyeprice23]

Re: G&G GR4 CQB-R 270fps?

take the cylinder and piston out, remove the piston, take off the large black o-ring and stretch it over the cylinder, heat it briefly with a lighter (really briefly, dont melt it!) and after about 5 minutes, take it back off and put it on the piston, then put your finger over the nozzle, and try push the piston in, you will then know if you have a good air seal, as if it pushes all the way down easy, then its the airseal, but if it wont go down with your finger over the nozzle, good seal...might sort it out...had a smiliar problem on my troy..over time the o ring shrinks. you say it was like that from new, but it may have been stored in a freezing warehouse for yonks!

[Noenine]

Re: G&G GR4 CQB-R 270fps?

Thanks for all the advice I'll open it up and check it all out. If it all goes wrong I'll give it to someone that knows what they are doing!

[Phatvortex]

Re: G&G GR4 CQB-R 270fps?

take the cylinder and piston out, remove the piston, take off the large black o-ring and stretch it over the cylinder, heat it briefly with a lighter (really briefly, dont melt it!) and after about 5 minutes, take it back off and put it on the piston, then put your finger over the nozzle, and try push the piston in, you will then know if you have a good air seal, as if it pushes all the way down easy, then its the airseal, but if it wont go down with your finger over the nozzle, good seal...might sort it out...had a smiliar problem on my troy..over time the o ring shrinks. you say it was like that from new, but it may have been stored in a freezing warehouse for yonks!

For the love of god, just buy another oring, they cost peanuts! In fact they cost less than peanuts!

Heating it like that will potentially damage the oring, and if not it'llshrink again in short order