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NPAS + Power Up Suppressor

NPAS Power Up Supperssor

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#1 ps6379

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Posted 05 May 2013 - 06:59 AM

So i recently acquired the RA Tech NPAS kit for my KWA MP7. On stock it shoots an average of 400++ fps without the power up suppressor and 500++ with the suppressor on green gas. I acquired the NPAS kit so id have the fps lowered. With the NPAS kit installed, it now shoots 350fps. (but i read somewhere that you have to use the stock spring instead of the 1 that came with the kit to reach at least 370fps) im happy with the new fps output (350fps at max) but when i put the power up suppressor (theoretically it will add another 100fps or so to the gun) it doesn't do anything. fps values stay the same which baffles me.

My goal is to use the suppressor and reach a maximum of 450fps.

Help

#2 akiraspeedstar

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Posted 05 May 2013 - 06:48 PM

The power suppressor boosts fps because it gives the gas more time to expand. If you usually see a shot from a stock MP7 it actually spits out a decent amount of visible gas behind the BB. With the NPAS you have less gas entering behind the BB meaning its less to expand and build up pressure. Possibly the amount of gas expands to its fullest before even utilizing much of the power up. Try to boost your fps back up on the npas and try again with the power up.

Also a heads up, I had a power up on my mp7 and it pushed my inner barrel back 2mm. Also damaging the barrel clip and outer barrel in the process

#3 ps6379

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Posted 06 May 2013 - 06:07 AM

Hi akiraspeedstar, thanks for replying to the topic. anyway, i've tried maxing out the fps (closing the valve) to no avail. (maybe im doing it wrong.. i'll try to open it then close it manually when i disassemble it) Im actually considering getting the tonic valve to replace the npas valve but ill see what i can do first (will try to change springs)

re power up, ill check the barrel clip and outer barrel. read a few things about it so im quite careful putting the suppressor in. (i dont let it click and slam on the inner barrel)

#4 ps6379

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Posted 07 May 2013 - 02:23 AM

so i visited my gunsmith (since i dont have a chronograph) and we've replaced the spring from the RA tech npas kit to the stock one. 390fps @ .20g on a hot mag with the power up suppressor on. averages 370fps (room temp) with the npas valve closed and with the suppressor on.

my target is still 450fps.. what items do i need to replace to increase fps? (still leaving the npas on so it will be adjustable) ive thot about replacing the barrel (160mm) to a 6.04 or 6.03 to compensate for the pressure...

your thoughts?

#5 kwaispro727

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Posted 08 May 2013 - 05:10 AM

Well I don't have any experience with the npas, but I can tell you that you should NOT use the power-up supressor.  You can go look at the barrel and clip now if you want (like akiraspeedstar mentioned), but you probably won't see anything bad.  The damage is long term.  Using the supressor a few times won't damage it.  The basic problem is the supressor requires putting too much pressure on the internals to consistently do it's job.  I tried putting washers together instead of using the black spacer inside the supressor, but when doing that there isn't a good enough seal between the two barrels.  At the end of the day it's not worth it.

Regarding your goal of 450fps, the easiest way to increase it on the MP7 to my knowledge is simply changing the barrel.  If you can find a 6.03 in stock length, that should get you there, maybe just a little under or over depending on what you do with the valve.

#6 ps6379

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Posted 21 July 2013 - 11:29 PM

So i've decided to drop the angry gun suppressor due to its ineffective accuracy. i've decided to go to Edgi and got myself a custom 365mm 6.02id... installed it myself and borrowed a chronograph from my friend and did some tests using 2 kinds of valves and 2 kinds of valve springs. Used the angry gun power up suppressor as a barrel shroud. An expensive one i should say... LOL

When i got the barrel i said wow... shiny... inside and out... when you look inside, it has a mirror finish.. brass and not too heavy.

Note: I modified the RA Tech NPAS valve. Shaved 1mm from the body's diameter and 1mm from the top. (was not able to test this as i did it simultaneously when i got the barrel. i should have tested it first to see if there is a significant difference)

Baseline stats:
1. Mp7 with stock valve and stock valve spring on stock barrel with angry gun power up suppressor, the gun shoots 531fps average of 3 shots using .20g bb, green gas and mag at room temp. (this i got to measure before upgrading)

2. Mp7 with non modified NPAS valve using NPAS valve spring with angry gun power up suppressor, the gun shoots 355fps average using .20g bb, green gas and mag regardless if at room temp or increased temp (used this setup for 2 games)

3. Mp7 with non modified NPAS valve using stock spring with angry gun power up suppressor (ive been using this setup for months), the gun shoots 380fps average of 3 using .20g bb, green gas and mag regardless if at room temp or increased temp

Chrono results after installing barrel and interchanging valve parts:
1. Mp7 with custom edgi barrel with stock valve and stock spring - 562fps average of 3 shoots using .20g bb and green gas at room temperature

2. Mp7 with custom edgi barrel with modified NPAS valve and NPAS spring - peak adjustment 401fps average of 3 shots using .20g bb and green gas at room temperature. 29% decrease in power. adjustable gas output.

3. Mp7 with custom edgi barrel with modified NPAS valve and stock spring - peak adjustment 426fps average of 3 shots using .20g bb and green gas at room temperature. 24% decrease in power. adjustable gas output.

One thing i noticed using the modified NPAS is that before the fps reading will remain constant regardless of what temperature the magazine is at. Now, when i measured the it using a "hot mag" it increased to 436fps average of 3 shots using .20g bb.

Accuracy:
In terms of accuracy i was not able to measure it to the full extent since i have little room to shoot with and i spent all the green gas i had left. But i was able to measure it at 30ft. Works like a charm. Less than 1 inch groupings at that distance without a stable base shooting sitting down... also, at that distance, i shot at 2 second intervals... but if you double tap with less than a second as an interval the 2nd bb will land directly on top of the first. =)

Edited by ps6379, 21 July 2013 - 11:30 PM.


#7 EdGI

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Posted 24 July 2013 - 11:13 PM

Im glad the barrel performed well

EdGI
http://www.facebook....EdGICustomWorks

Edited by EdGI, 24 July 2013 - 11:20 PM.






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