HI, new here.
I have had a KWA mp7 since they came out, and the gun has run flawlessly for me. Only problem I have ever had with it was a 10 year old seal finally giving up. No problem, just replaced it with a new one, and off I went. I've only played indoors, but am getting ready to start doing outdoor stuff, and thought running a mp7 with a 370mm barrel might be fun.
So here we go: I purchased a used beat up listed for parts mp7 on eBay. The previous owner said it wasn't operating because it needed a new bucking. Bucking was fine, it needed a new piston seal. I replaced the piston seal and ran it for a couple of weeks to work out any other problems that it had.
The body came with a cracked rear(by the pins of course). So I ordered one off of Rainbow8, and transplanted the internals to the new body. While I was taking the whole thing apart, I threw in a TN.T 370 barrel and bucking kit. The inner barrel wall is a lot thicker than standard barrels, so it came with an outer barrel too(they include a 12mm to -14mm adaptor too which is nice). The bolt carrier was banged up and had parts broken on it, so I purchased a new one and figured I would try a TN.T piston 'upgrade' while I was in there. It uses an o ring instead of the seal cup. I figured if parts become unobtainium, I could always find a new o ring.
So all together now, and it seems to cycle and kick like it's running well. But the FPS dropped to 180 FPS with .20s. I swapped bolts with my stock gun, and the bolt was running 330 FPS with .20s(I should mention that the bolt was set up for cqb). So it's not the bolt. Thinking that the hopup might be swollen, so turned the hop all the way off, and no change.
Not a lot of GBBR info to be found about these upgrades. What I understand is that I should see FPS increase, just because the barrel length if nothing else. So I'm wondering if the nozzle spring could be the culprit. Is the valve getting shut off before it should, causing the gun to shoot low? I'm thinking of trying a stiffer spring in the nozzle...
Thoughts?
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I have had a KWA mp7 since they came out, and the gun has run flawlessly for me. Only problem I have ever had with it was a 10 year old seal finally giving up. No problem, just replaced it with a new one, and off I went. I've only played indoors, but am getting ready to start doing outdoor stuff, and thought running a mp7 with a 370mm barrel might be fun.
So here we go: I purchased a used beat up listed for parts mp7 on eBay. The previous owner said it wasn't operating because it needed a new bucking. Bucking was fine, it needed a new piston seal. I replaced the piston seal and ran it for a couple of weeks to work out any other problems that it had.
The body came with a cracked rear(by the pins of course). So I ordered one off of Rainbow8, and transplanted the internals to the new body. While I was taking the whole thing apart, I threw in a TN.T 370 barrel and bucking kit. The inner barrel wall is a lot thicker than standard barrels, so it came with an outer barrel too(they include a 12mm to -14mm adaptor too which is nice). The bolt carrier was banged up and had parts broken on it, so I purchased a new one and figured I would try a TN.T piston 'upgrade' while I was in there. It uses an o ring instead of the seal cup. I figured if parts become unobtainium, I could always find a new o ring.
So all together now, and it seems to cycle and kick like it's running well. But the FPS dropped to 180 FPS with .20s. I swapped bolts with my stock gun, and the bolt was running 330 FPS with .20s(I should mention that the bolt was set up for cqb). So it's not the bolt. Thinking that the hopup might be swollen, so turned the hop all the way off, and no change.
Not a lot of GBBR info to be found about these upgrades. What I understand is that I should see FPS increase, just because the barrel length if nothing else. So I'm wondering if the nozzle spring could be the culprit. Is the valve getting shut off before it should, causing the gun to shoot low? I'm thinking of trying a stiffer spring in the nozzle...
Thoughts?
