Snarf
New Member
Ambidextrous selector switches are the bane of my existence
Posts: 560
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Post by Snarf on Apr 20, 2014 21:03:45 GMT -5
That sounds like a legitimate point. I never vented the mag because I didn't want to freeze the O-rings, but when I filled them they only made noise for a few seconds. Like the noise of transferring gas didn't continue very long before it stopped. Since this was consistent with all three mags I didn't think it was a problem, but it might be the gas capacity of the mags themselves. If you have the money, try just buying a new mag. I could have just gotten 3 dud mags from ASGI when I bought it.
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Post by Shadow (314) on Apr 28, 2014 20:29:31 GMT -5
I've definitely concluded that a "break in" time for KJW mags are both true and false. I've discovered that the spring metal used for the release valve in the mag is of poor quality and is often too strong at first and breaks in quickly to a more consistent level after use. This is the spring and nothing else to the with the mag. This I've discovered for myself by working with old and new springs. The new spring fired with a little less FPS but I did get an average of 2 more shots from it. Also, I've heard numerous reports that the rubber seal on top the mag that should lie flush with the gun valve often has seams and junk from the manufacturing process that often wears off after use, therefore making a better seal. I haven't experienced this myself but, it makes sense. What I did was to smooth the rubber lip a little with very fine oiled sandpaper and then shim that rubber lip so that it pressed against the gun harder. This made a noticeable increase in FPS but I didn't seem to get any more shots from my 23 round mag. I was still stuck at 6-7. Next, I'll be replacing the seal inside the blowback valve/action and the recoil spring to see what that does. I'll be using a PDI hi-cappa recoil spring that will be cut to give just enough force to cock back the hammer and feed the next round, but no more. I've heard good things about repairing or replacing the blowback piston head, and the recoil spring should give me faster follow up shots. I'll report back when it's done. Probably 30 days. The next adjustment after that will be a new hop up bucking and the teflon tape seal. This will be to ensure that minimal gas escapes that direction.
EDIT: My question now is, what can you tell me about the workings and compatability of the valve and blowback action inside the gun? I'm hoping to use a nine ball head but, what will fit? Google has little on this and what is there is in-consistent. From what I can tell, most parts should be TM compatible but, I'm not sure and would like some advice here.
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Snarf
New Member
Ambidextrous selector switches are the bane of my existence
Posts: 560
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Post by Snarf on Apr 28, 2014 20:42:19 GMT -5
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Post by Shadow (314) on May 1, 2014 17:56:30 GMT -5
Ok, so now I know I want to replace the Piston head inside the gas chamber. Parts 4A and 4B. I also am looking into getting a better seal or replacement for the Cylinder Valve, part 14. Does anyone know if this is a standard part for all TM clones or is this something that is particular to a KJW KP-02?
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Post by TheEnd on May 1, 2014 21:25:01 GMT -5
I've definitely concluded that a "break in" time for KJW mags are both true and false. Still false. I've owned a handful of KJW's and none of them required a break in. Further more almost every GBB pistol uses the same valve design (design, not dimensions). If KJW mags required a break in so would every other pistol. I'm also fairly certain the spring does nothing more than prevent the gas from holding the valve open after the fire cycle is completed. The gas pressure itself probably forces the valve closed. 100 psi of propane is a lot stronger than that dinky little spring. If my reasoning is correct the force the striker valve spring applies should be irrelevant to gas efficiency as long as it is within a reasonable ratio to the hammer spring. what that ratio is I have no clue, but I would hazard a guess you can't "feel" it. I thought about your issue some more, and I think it may be related to your firing pin. Even a terrible gas seal in a GBB will get more than 7 shots per full mag. While testing different O rings in my WE 416 GBBR (Buna-N, silicone, urethane, Viton, natural rubber) I had some O rings which cracked or were cut during cycling. My 416 has a steel bolt which is pretty heavy (granted a larger gas reservoir as well) but still managed to work fine during a CQB game while a huge chunk of the natural rubber O ring was missing. Point is, even with a shitty gas seal you will get more than 7 shots out of a conventional GBB as long as the mag is full. If your gas seal leaked bad enough to dump a mag in 7 rounds you would have liquid propane shooting out from between the slide and frame, out the chamber, and most likely in the barrel. Your pistol would most likely have a slick oily film all over it. I think your firing pin might be to blame. My theory is that your firing pin isn't pressing the valve enough and causing a light strike. When your mag is 100% full it has enough power to cycle the slide with a light strike. For example your striker valve is maybe opening only 30%. At 100psi (full mag) 30% of the valve travel is enough to cycle the slide. At 50psi (after a few rounds) 30% of the valve travel is not enough to cycle the slide. This would explain why all three mags have the issue but seem to be fine on their own. The O ring on the striker valve could also be over compressed which would cause the valve to sit too far into the mag. Try loosening the striker valve a little if you have the tool. To prove this false fill the mag, shoot the pistol as many times as it can cycle, then vent the mag. If you get nothing, back to square one. If you get a big rush of pressure you can check the firing pin to striker valve clearance.
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Post by Shadow (314) on May 3, 2014 19:59:59 GMT -5
Great idea. I didn't think of that. I just tested it by filling the mag, firing the gun until it won't fire, then pressing the valve to see if there's any gas left. Unfortunately, the mag was completely empty. I tried this will all three mags, twice each.
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Post by Shadow (314) on May 17, 2014 18:11:12 GMT -5
Ok, there's one last part I haven't replaced or tried others for yet. The loading nozzle and/or the valve inside the loading nozzle. Now, I've searched evike, airsoftatlanta, and eBay and nothing is coming up for valves with a tag for kjw sig 229 or anything I saw that might work. Does anyone know what valve or nozzle replacement would be comparable with this gun?
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