GBB Pistol Mag Filling Help

[sonicninja]

Hi all,
Just wondered if a few of you gas gurus can give me a little advice.
I'm having some issues with my range of KWA NS2 Pistols and specifically their mags.

Basically I'm not convinced they're filling correctly with either my abbey brut or abbey ultra gas. I fill as you should (gas can upside down) in a warm room in my house with room temp gas mags. When I fill I hear no sound of gas going in and I can be sat there for absolutely ages with no gas spewing from either the mag or can.

The reason I ask is that I recently had a SD slide installed on my USP and have had issues revolving around limited slide movement. I'm now wondering if this is actually just down to low gas content/pressure in the mag.

Any help would be great, happy new year all.

[Sidewinderforge]

Re: GBB Pistol Mag Filling Help

They are silent fill valves so there will be little noise from them, couple of 5 sec blasts should see them full.

A different (esp heavier) slide will require more energy to blowback so a different recoil spring might be needed.

SAS

[loki7491]

Re: GBB Pistol Mag Filling Help

Is the new slide heavier or did it come with a stronger return spring? If so, you may just need a more powerful gas as what you are using isn't man enough for the job.

Is the new slide a good fit and moving freely?
You may need to rack the slide a few times, remove it and look for witness marks of rubbing. File down any high spots.

To be certain it is the new slide, restore to factory finish and do a comparison.

[sonicninja]

The new slide is heavier but I upgraded to 150% springs in the process too. The slide moves freely, it didn't originally but has now bedded in.

Are stronger gasses available? I was under the impression green gas was comparable to propane and red gas was really used anymore.
Cheers for the reply.

[loki7491]

Re: GBB Pistol Mag Filling Help

150% springs?

I think that could be your issue. Strip the slide, the spring at the front is the return spring... if it is now stronger to snap the slide forward faster, it is also stronger in resisting the backward motion of the slide due to the gas.

You are using the same gas but asking it to move a heavier object, with a stronger spring resistance

Put in the original return spring and try again. It should improve.

[sonicninja]

I have actually tried this with no change although I thought that it was common practice to upgrade to 150% springs when replacing slides that are heavier. What you've said is logical though.

Both my stock spring and 150% spring are exactly the same length however so I wonder if the 'stock' (which came with the used gun) is also 150%.

[loki7491]

Re: GBB Pistol Mag Filling Help

Look at the thickness of the spring wire and how many coils there are per inch.

To strengthen a spring, make the wire thicker or add more coils per inch. You could have an almost limitless amount of springs the same length, but with different ratings simply by manipulating these two aspects.

Did you add a stronger hammer spring too? So it hits the valve harder, opening it further for longer and thus allowing more gas out with each shot?

[sonicninja]

Again, I tried it but it made the trigger pull stiff to the point of making the pistol completely useless in a skirmish sense.

[sonicninja]

Sorted. It actually wasn't the recoil spring but the secondary smaller spring the sits on the same rod. It wasn't moving freely as the pin holding it in has bent. No idea what this smaller spring does but now it's fixed the whole thing is kicking like an absolute mother and locking back correctly. Bingo!

Cheers for the guidance all!

[dave38x]

Re: GBB Pistol Mag Filling Help

Drives me to distraction how it's always something that you check last that's the root cause!