kwc sigpro

I found my sigpro that kwc makes it's a Co2 non blow back. I want to try to field it before the summers over but my mag leaks gas then it stops after about 5 minutes and leaves Co2 to shoot. my first question is do all Co2 guns do that leak gas when it's first put in buts stops leaving gas (I'm not sure myself the gun was donated to me) second can sombody please link me to a site that has mags for this gun.

Ehh sorry for the double post if anybody actually reads this but I did find the magazine I need.

http://www.shortyusa.com/airsoft.html?http://www.shortyusa.com/cart/viewitem.html?II=1166&UID=1276896557-174.45.156.31&CA=&RID=

it's from shortyusa and I haven't heard much about them so I'm not sure if they are very good. I have looked this up on google count less times and ran across it here so ehh can somebody get me a link to a better site that has the mag so I can just be sure.

co2 guns shouldn't be leaking gas.

yeah thats what i thought but it leaks for about 5 minutes then all of the sudden it stops and holds the gas perfectly again i went over to my team leaders house to chrono it. it shoots about 10 fps less after the leak.

heres the stats
co2 put in with leak

367
372
369

after leak noise stopped
360
358
358

I don\'t think it really effects the fps to much. So I don't mind this mag will be a spare mag and ill use the new one from the begging and this will be kind of a desperate times mag.

just make sure when you put the co2 in all the way
my last co2 gun (and my only one and my last one forever) had a screw on the bottom of the pistol grip that screwed up and punctured the co2 canister. so if yours is the same make sure you have it screwed up/in all the way

yeah its screwed all the way nice and tight, i think the little o ring around the pin thing is messed up. i personally don\'t want to take it apart untill i get another mag. it doesnt effect the performance to much though.

You said it stopped leaking after a while? Could it be because a full Co2 Canister is too much pressure for the O-ring, but after some of the pressure is released it works normally? Thats the impression I got from the stats in your post

hmm thats very likely because its held co2 for a day now and still is holding.

but i asume people only read one question at a time here, so heres the other question. how is shortyusa except expencive since thats the only retailer i have found that has mags for this gun.