More mods on the iguana hunter

More mods on the iguana hunter

Joined: September 7th, 2009, 10:49 pm

March 24th, 2011, 2:20 am #1

Today I decided to try some mods on my project "evolution" 2300KT pistol. I removed the valve and enlarged the exhaust port to 11/64th, changed the angle entering the port, and installed a new valve seal that came with the HiPAC for pressures above 2k psi. Next I'll post chrony#'s.

Last edited by turbonoma on March 24th, 2011, 10:22 pm, edited 1 time in total.
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Joined: September 7th, 2009, 10:49 pm

March 24th, 2011, 10:24 pm #2

Today I did a little more work on the valve. I started by rounding the base of the valve stem and then proceeded to cut off the piercing pin. Next I'll upgrade the valve set screw by drilling straight through the valve body and tapping for a #8-32, then cutting 1/4" below the head. I read some where that I could use the striker spring instead of the stock valve spring by making it 1/8" to 1/4" longer being that the striker spring is lighter. Any thoughts on this?
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Joined: March 16th, 2003, 11:14 pm

March 25th, 2011, 2:25 pm #3


The "How to" was written (and has photos) by user "Biohazard" of the "Bio valve" fame.

Good luck,
Lorrin
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Joined: September 7th, 2009, 10:49 pm

March 28th, 2011, 4:22 pm #4

Thanks Lorrin, that's the post I got my info from.
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Joined: September 7th, 2009, 10:49 pm

March 29th, 2011, 12:56 am #5

Today I shot the Iguana hunter and here are the results. I used CPHP(14.5grns.) and some Peak(13.9grns.)pellets. After the work I did to the valve, I am disappointed with the velocities. The Peaks shot at 307fps and the CPHP shot at 287fps. I shortened the striker spring and made it 1/4th longer than the the valve spring since it's lighter. Made the exhaust port larger using an 11/64th drill bit,eased the port angle,cut off the piercing pin,and rounded the stem. I was hoping for better
velocities. Next I'll try a stiffer hammer spring and report back my findings.
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Joined: March 16th, 2003, 11:14 pm

March 31st, 2011, 2:34 am #6

My gun has a valve spring that is really light, I can depress the valve shaft easily with my little finger and it is difficult to depress the hammer spring with a finger. I used a digital postal scale to measure the spring tension of both springs when I built my gun and I seem to remember that the hammer spring was about 3 or 4 times the strength of the valve spring. Remember that the hammer spring has to open the valve against the air pressure inside the valve also ( 2000 pounds in your case ). I bet your valve is not opening much at all unless something else is wrong with the gun's operation right now.. You don't have to disassemble the gun very far to try a heavier hammer spring. How long is your barrel?
I remember that I used the stock hammer spring and a much lighter valve spring than stock...
Remember to have the bolt cocked when you fill the gun from empty so that the hammer spring is not holding the valve open when you first fill the gun. If you don't do that, the air will just exit through the valve and out the barrel.
Good luck, Lorrin
Last edited by leel on March 31st, 2011, 2:44 am, edited 1 time in total.
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Joined: September 7th, 2009, 10:49 pm

April 4th, 2011, 1:06 am #7

I substituted the stock hammer spring cut 1/4th longer for the stock valve spring. Then I used the red hammer spring supplied with the HiPAC. The gun currently has a 10" barrel and I'm going to purchase a 14~16" barrel with the hopes that it will bring up the velocities.
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