15 replies to this topic

[NSoft]

I just purchased the USP Tactical Compact, and was wondering if it was usual for a full mag fill with a new can of green gas to only last around one mag or slightly less. My UHC VP-70 gets at least two mags...

[xKingSizex]

You should get more, but it also depends on the temp...which I'm assuming is warm right now so that shouldn't be the issue.
How long are you filling the mag and have you tried another can of gas yet? Sometimes even new cans can have low pressure.

[gcw360]

What brand are you using and is the nozzle integrated or do you need to screw it on?

[NSoft]

xKingSizex, on 09 September 2011 - 05:01 PM, said:

You should get more, but it also depends on the temp...which I'm assuming is warm right now so that shouldn't be the issue.
How long are you filling the mag and have you tried another can of gas yet? Sometimes even new cans can have low pressure.

It is warm, I've filled both mags for about 5 seconds and somehow the UHC still pulled off almost an entire magazine more.

edit: integrated nozzle

Edited by NSoft, 09 September 2011 - 05:13 PM.

[gcw360]

Try 15-20 seconds.  The other model (UHC) may allow the gas to go in faster and you may only be getting the KWA to about half full.  It's worth a try.

[mcnabb100]

Yeah, somethings not right if you are only getting a mag. I can squeeze four out of my full size if I'm just doing slow target shooting. I would expect the compact to get two out now problem.

[xKingSizex]

Yeah, 5 seconds won't fill the mag. 15-20 seconds should get you filled.

[niko_gpsy]

I fill my mags at 5 second intervals 3 times.  I could, on a warm day, get almost 2 mag and a half with all of my ns2 guns.  You are either not filling them enough or filling them incorrectly.

[NSoft]

Okay, tried 15 second fill, 3 second interval, only got 22 rounds. My buddy with the same gun (full size) reports the same problem happens to him a lot as well, so that's why I was wondering if the problem was related to KWA's NS2 gas system. When the can stops hissing, the reservoir is full, right? Not sure if it matters. but it's a KWA branded green gas can.

[niko_gpsy]

When the mag is full you will have gas hissing out of the can.
Do you notice any gas leak from mag anywhere?

Maybe it's a fill valve problem. Start a warranty ticket with the help desk. They will fix that up for you.

[xKingSizex]

Have you tried another new can yet as suggested?

[alanbolt]

Just got the USP Tactical on Wednesday,  and I may be having a similar problem. I was out at my "range", and had what appears to be more trouble than normal filling the mags with gas. This was the first time out with this piece. I was barely getting the thing to empty the full mag.
My KSC G23F on the other hand being filled from the same can, had no problem.
I tried removing the base plate on the bag, (No lever. You have to use a pen to push the button down to slide the thing off )
Still same result.
Ill try the 3 x 5 second method with a new can of  gas.

[gcw360]

I count to 20 usually when I fill my mags....just out of habit.

[philsaudio]

With my new ATP I lube the fill valve o-ring and count to 15 while filling. There is no hissing. Hissing means you do not have a good seal. What is happening is you are pouring liquid propane from the can to the Mag. Hissing is a bad seal and wasted gas. If I then put the mag into my pocket and heat it to over 80 deg F before firing I am getting 3 solid 23 round uses with the slide locking back and usually a fourth where the slide will not lock back on the last shot. At least three.

I have started weighing the mags too. One is 309 grams empty and will be 313.5 grams full. I measure temp with a non contact thermometer. I am just getting started with the measurements and will post a little more as I understand more.

Another parameter I need to get a handle on is how the temperature of the green gas can and the empty mags weigh into the filling equation.

Does anyone know the gas weight in grams capacity of the ATP mags?

Edited by philsaudio, 14 January 2012 - 07:24 AM.

[forty2]

I primarily use King Arms green gas and I find that filling my USP mags can be finicky. I don't know than I can really explain it but I've developed a feel for when it's filling properly and it hasn't been much of a problem. I also have a WE 1911 and the mags for that aren't nearly as touchy, still prefer the KWA though.

[philsaudio]

I weighed the mags and found that the 23 round mags take 8 grams of green-gas while the 50 round takes 20 grams of green-gas. I marked the empty and full weights of each mag on them so at least I know they are full when I leave home. Carrying a triple beam scale to the field would be a bit much.

If you know your weights there is no more guessing.


BTW I am getting 9-11 BBs per gram


Also if you are having problems getting those last few grams of propane into your mag, try warming the fill can with your body for a while. And for you youngins, pay attention in physics when the IDEAL GAS LAW is covered any you will be less likely to fall prey to the "pressure and counting" BS. There is no magic to gas just because it is airsoft.

Hanibal says ,"And no Cigars! At least not lit Cigars. If your forget to lube your mag and it vents, that may result in a nice fireball in your face."

Peace

Edited by philsaudio, 30 January 2012 - 02:12 AM.