To all you gas gun techies, Gas problems with pistol

[x-ray]

Hi all,
Recently bought my self a TM XDM and have put alot of money into it however I am somewhat disappointed that using higher pressure gasses will make the gun not cycle but fire the BB or it will cycle but at nowhere near the blowback it should be for that gas, the gun does have a reinforced loading nozzle tightbore etc but does not have an uprated cylinder valve and piston head (Fire Fly (Cylinder Valve and Piston head) for Marui XDM Pistol.) I have ben told installing one of these will mean it can handle higher pressure gasses with ease. The pistol as it is now will fire once there is less gas in the mags due to the lower pressure in the mags but only enough for a few shots.

Is it worth buying the Fire Fly (Cylinder Valve and Piston head) for Marui XDM Pistol as otherwise this pistol is just going to have to go...


Cheers X-ray

[heroshark]

Re: To all you gas gun techies, Gas problems with pistol

The valve is better kept standard . Is the standard head the cup type or o-ring?

[x-ray]

Re: To all you gas gun techies, Gas problems with pistol

Cup type which seems to be made of a flexible silicon plastic.
this is a pic of the actual item im thinking of getting for it here the actual cylinder head I may not use as it causes problems with the loading nozzle not cycling properly, the silver bullet looking thing is the part im most interested in, the stuff inside the pistol at the moment is all plastic which may be the cause of the problem if I remember correctly there is not any parts inside the gun now that resembles the silver bullet like thing...

X-ray

[dadio]

Re: To all you gas gun techies, Gas problems with pistol

what higher pressure gas are you using? on one or two occasions i have come across a case here the gas is at such a pressure that release valve jams and does not release enough gas but that has only happened in hot weather on propane not at this time of year unless you are using co2 in a regular magazine.
start back tracking by removing the upgrades one at a time until it works again then add them again one at a time till you find the offending part.

[Boo-Sabum Ben]

I would swap the springs for nine balls smooth spring set as well. The hammer spring is far too stuff in my opinion

[x-ray]

Re: To all you gas gun techies, Gas problems with pistol

Ben will try new springs then :D . Dadio I have tried just that and it seems to get worse depending how much im taking off. The gas I use is call Guarder Black Gas this stuff worked flawlessly in my 5-7 and the Glock 17 (both stock and TM) so starting to loose patience with a £400 paperweight....

[heroshark]

Re: To all you gas gun techies, Gas problems with pistol

Like I said your best off sticking with the standard valve . The up rated valve sends more gas down the barrel than the regular one decreasing what goes into the blow back.

[x-ray]

Re: To all you gas gun techies, Gas problems with pistol

Right will stick with the stock one then, will try upgrading the springs on it and see if thats any better apart from that im stumped

[dave38x]

Re: To all you gas gun techies, Gas problems with pistol

x-ray - sounds like you need to upgrade the hammer spring!

Heroshark - thats not how high flow valves work - they dont change what they send gas proportions too - they just release a lot more gas, so more goes down barrel, but rocket valve snaps shut quicker, more gas left for blowback.

[x-ray]

Re: To all you gas gun techies, Gas problems with pistol

Nineball springs all round then it seems :D should be fun installing it

Cheers chaps for your help,
X-ray

[heroshark]

Re: To all you gas gun techies, Gas problems with pistol

x-ray - sounds like you need to upgrade the hammer spring!

Heroshark - thats not how high flow valves work - they dont change what they send gas proportions too - they just release a lot more gas, so more goes down barrel, but rocket valve snaps shut quicker, more gas left for blowback.

The gun only let's same amount of gas each time the hammer strikes ,the amount is determined by the mag valve not the bbu valve. The gas goes into the bbu where its shared between the blow back and the barrel . The high flow valves have 2 instead of 4 prongs to allow more gas through while is open . Some also come with a harder spring so they stay open for longer. You can cut 2 of the opposing prongs on the standard tm shut off valve to get the same effect.

[Boo-Sabum Ben]

X-ray.

Before you buy new parts, so a simple assemble of the hammer spring area.

When I had mine, it was totally sporadic on whether it would fire pathetically, or strongly.

What had happened is it had been dropped at some point and the hammer spring shifted to an awkward place. (As far as I know. My local gas tech bought it off me to fix it) so check and see if that's what's happened first.

The nine ball kit is actually weaker springs, not stronger ones. If you cock an XDM then cock say a Glock or 1911, you'll notice the XDM is a lot stiffer. That's what the nineball kit fixes

[heroshark]

Re: To all you gas gun techies, Gas problems with pistol

It's much cheaper to crop the standard spring if that's the issue.

[x-ray]

Re: To all you gas gun techies, Gas problems with pistol

So I dont buy the new springs?

[heroshark]

Re: To all you gas gun techies, Gas problems with pistol

Try cutting a couple of coils off the standard spring . You can always shim the spring if you've gone too far to increase the pressure . You can do the same on the recoil .