If you have an MK11 with the standard plenum in .25 cal. and have added the M14 External Plenum what kind of power increase have you experienced? And at what price? I'm thinking of doing this but haven't heard much on the .25cal.. Shooters are getting 1000fps plus velocities with the .22 and 30cal. I'm interested in shooting the JSB 34's and the heavier slugs 33 - 40gr in the 920 to 1000fps range. What kind of velocities and what reg. pressures do you need to get the higher velocities when using the stock plenum at 28cc and the M14 at 52cc.? Those numbers were taken from a customer that had Ken Hicks build his gun. I realize that more work needs to be done besides just adding the external plenum. Thank you.
Impact MK11 with M14 External Plenum
- Thread starter hotair
- Start date
I shoot the 34gr. JSB's at 965fps and the 32.8gr VK slugs at 985fps with my regulator set at 140bar and hammer spring almost maxed out. When I was testing slugs all the time I could get quite a bit more velocity than that with some of the heavier slugs like the 33.5gr, 34gr, 36.2gr, but my reg. was as high as 160bar.. You should be able to reach those velocities pretty easily.
I did make the internal modifications too, plenum, probe, C3 bumper, hammer weight, etc... I can't help you with price, I don't know what the stuff costs, sorry.
You'll like the end results!
Stoti
I did make the internal modifications too, plenum, probe, C3 bumper, hammer weight, etc... I can't help you with price, I don't know what the stuff costs, sorry.
You'll like the end results!
Stoti
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Thanks brotha, I like to show her off. She's a shooter.
Hey Hotair, one variable is that my external plenum is more than 52cc. I can't remember the volume, but I'll find out for you.
Stoti
Hey Hotair, one variable is that my external plenum is more than 52cc. I can't remember the volume, but I'll find out for you.
Stoti
Upvote 0
Thanks for the reply stoti,
I'm a bit undecided on what to do. The Impact MK11 that I have has the power plenum. I was thinking of changing the plenum to the standard MK11 plenum like yours and then adding the external M14 to get more power. Originally this gun topped out at 120bar, anything more yielded nothing, and with the hammer fully maxed I could only get 920fps with the 34 JSB's. I've changed the hammer spring to the 57mm and put a ''very'' lite valve spring, instead of a heavier hammer, and a delrin stop in the valve cap to make sure the valve rod didn't blow out the other end. Then I ported the transfer port and matched the factory probe. Now the 34JSB's go 980fps and the NSA 36gr go 953fps at 130bar with the valve opening .150''. Anymore reg. pressure does nothing. You know how it is ''too much power is just enough''. Maybe what I now have is good enough. I was going to make a pin probe but am wondering if that's a waste of time. I haven't heard much about their results in the .25cal. Have you tried one?
What kind of accuracy are you getting with the VK slugs at 100yds and what liner are you using? I've been waiting to get the new superior heavy liner for months now--still nothing in sight.
I'm a bit undecided on what to do. The Impact MK11 that I have has the power plenum. I was thinking of changing the plenum to the standard MK11 plenum like yours and then adding the external M14 to get more power. Originally this gun topped out at 120bar, anything more yielded nothing, and with the hammer fully maxed I could only get 920fps with the 34 JSB's. I've changed the hammer spring to the 57mm and put a ''very'' lite valve spring, instead of a heavier hammer, and a delrin stop in the valve cap to make sure the valve rod didn't blow out the other end. Then I ported the transfer port and matched the factory probe. Now the 34JSB's go 980fps and the NSA 36gr go 953fps at 130bar with the valve opening .150''. Anymore reg. pressure does nothing. You know how it is ''too much power is just enough''. Maybe what I now have is good enough. I was going to make a pin probe but am wondering if that's a waste of time. I haven't heard much about their results in the .25cal. Have you tried one?
What kind of accuracy are you getting with the VK slugs at 100yds and what liner are you using? I've been waiting to get the new superior heavy liner for months now--still nothing in sight.
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I have the .25 MK2 PP 700 mm with a dual port/matching probe and all the rest of the gun is all stock, last time I checked, I got the 34 jsb's maxing out at 960 with a reg at about 125 bar.
These are numbers in my basement, no accuracy check because both shooting ranges around me all closed and my Impact still in the case since.
Shopping around for parts (hammer and weight, springs and don't know what else may be needed) but no dealers in Canada selling these and cannot find a single point to source.
Anybody can point me?
These are numbers in my basement, no accuracy check because both shooting ranges around me all closed and my Impact still in the case since.
Shopping around for parts (hammer and weight, springs and don't know what else may be needed) but no dealers in Canada selling these and cannot find a single point to source.
Anybody can point me?
Upvote 0