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#1 SuperSanta911



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Posted 30 November 2008 - 02:56 PM

im getting a KWA, M16 or M4 and im planning on installing a tightbore , Prommy.

I hear that raises the FPS a good 20- 30 so im also going to need to drop the spring.

Which spring should i use to get my setup just under 400 FPS with 20's

Like the 170% springs and stuff, i have no idea what that means.   The closest ive seen is the systema M120, or M110

Any help would be appreciated.


#2 Stealthmaster14



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Posted 30 November 2008 - 03:22 PM

I doubt it will increase your fps by 20, but I might be wrong.  (I believe it is more like 5-10 fps)

A PDI 150% will put you under 400 fps.

#3 ejec19glock



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Posted 30 November 2008 - 05:17 PM

it will not increase fps unless youre getting 363mm tightbore. Mine is 509mm 6.03 prommy spring settled around 380-390fps with .2s

#4 brooklyn468



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Posted 30 November 2008 - 07:07 PM

You may have enough to just do nothing, if you get the KM-4.

The spring settles around 390 fps, and the tightbore goes 5- 10 fps faster, than you should stay under the limit.

If you get the KM-16, you will have to downgrade, at least to an m120.

#5 Guest_Radix_*

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Posted 01 December 2008 - 05:00 PM

Give the stock barrel a chance before you decide to change it out. Most brass barrels need time to break-in. When you get the gun, clean the barrel really well and shoot a couple thousand rounds through it.   You may be surprised at the results. ;)

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