Lowering Pistol FPS

captainkirk05 · Post by **captainkirk05** » Sat May 19, 2012 5:00 pm

Chrono'd my KJW M9 a few times now. I remember it shot 309 fps and up with .25g and propane. Yesterday's chrono with .20g and King Arms green gas started me at 360 fps and settled around 340 fps. And yeah the hop up was cranked on for this too.

I bought this pistol for CQB use, but it shoots way hotter than advertised, and I can't use it under 20 ft, and not at all at some indoor places with 330 fps w/.20g limits. Is there a way to slow this thing down some?

I read the below forum topic but don't know if that applies to this type of pistol (and I simply don't quite get it)

Post by **SteevoLS** » Sat May 19, 2012 5:10 pm

Run it on duster gas instead of green gas or propane. That should bring it down to 200-something.

captainkirk05 · Post by **captainkirk05** » Sat May 19, 2012 9:21 pm

Might try that, though I'm wondering if it is safe to use in the gun, it was only labeled as using green gas, propane, and CO2 (bad idea btw).

Avenger · Post by **Avenger** » Sat May 19, 2012 9:23 pm

Duster is weaker, so it can't really hurt anything.

Keep it lubed up and clean and you're good to go.

Post by **SteevoLS** » Sun May 20, 2012 6:57 am

captainkirk05 wrote:CO2 (bad idea btw).

They're actually made to run on CO2, unless you mean the FPS difference is a bad idea.

captainkirk05 · Post by **captainkirk05** » Mon May 21, 2012 2:38 pm

Too many stories of the CO2 pressure prematurely killing KJW's, and yeah the fps would be out the roof. I'm going to get some 134a gas, of course with the gun designed to take green gas pressure gases for it's heavy slide and strong recoil/hammer spring, I'm wondering if it will be enough to cycle the slide.

Post by **SteevoLS** » Mon May 21, 2012 4:10 pm

If it has issues cycling on weaker gas, your best bet would probably be to find a plastic slide or sell it and pick up a TM.

captainkirk05 · Post by **captainkirk05** » Wed May 23, 2012 3:19 pm

A light bulb just turned on over my head!
You hear about these high output flow valves for sale on all of these magazines. I think I heard KJW includes theirs with high flow valves already. If you look at Evike's KJW M9 mag page, it advertises itself as shooting 5 - 10 fps more than HFC mags. So I wonder if the HFC brand "reinforced valve" (no high flow or output mentioned) on the site might have tighter openings to help lower fps... You can see the openings are far smaller than the other valves

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