Cricket 9mm is coming together

[vmaxpro]

I dont have much time anymore but got to do some more toying with the 9mm cricket. I posted awhile back about a balanced valve but ive got a “ perfected” version in it now. What a power house and effiecent too! Heres where im at:

.320 porting

Peek balanced valve ( .380 poppet, .245 secondary, urethane internal orings x2, .062 vent with .048 jetting in the back)

Light weight free flaoting hammer

Huge 6” plenum extension tube ( I made it)

Huma reg

1 degree leade after chambering for 125gr slugs. Very important on these barrels as I couldnt even chamber a slug.

Long story short, the stock hammer spring was waaayyy to much ( total plenum dump what a recoil!) I had a taipan spring laying around that would open the valve perfectly at 115 bar. What a suprise I had when the chrono showed 1020fps at only 115 bar with 81gr pellets. My end goal is 950+ with 125gr slugs. I think I’ll get there around 160 bar. Anyhow just wanted to share. Next up is boring out a koi to work and adapt it to the factory shroud to help even out the shroud to the tube and gain a little less noise. Heres a quick pic I took of the valve. You can see the small jets in the tube for tuning. This is unfinished but the only pic I took!

 

[gendoc]

thats really bad @$$ right there !!!!!
an awesome hunting rig

 

[vmaxpro]

thats really bad @$$ right there !!!!!
an awesome hunting rig

I hope I can get it accurate! Im working on a speed dialer like the vets use. If the valve plays nice I can quick back it off to 120-130fpe with pellets and over 200 with slugs easily. Before any modding the barrel was very very accurate at 100 yards with pellets so fingers crossed! My only concern is can the platform handle 200+ fpe.

 

[Ezana4CE]

@vmaxpro That seems to be coming along nicely. I don’t even understand the significance of all that you’ve done, but I’m impressed that you posses the time and skill to do it. Especially what you’ve done with the barrel. How do those 81 grain pellets perform at over 1000fps?

 

[mercado]

Awesome..all these years the 9mm cricket been the ugly duck.. I no body expected to be able to make such a good power house.. it would be great if you put for sale those parts so people could get the most of those crickets.

 

[vmaxpro]

Tinkered a little more today, I think I need a valve return spring which will be easy. At 160 bar I cant find a good balance between the jetting and valve dwell. Makes alot of power but wasting a ton of air. As far as the signifigance of it, I just really really like the looks and compact size of the cricket but wanted some more power for slugs from it. It would also not be easy without some sort of balanced valve in it.

 

[Pale_Rider]

Did you free float the hammer with a shorter, stiffer spring? Or make an SSG?

 

[vmaxpro]

Did you free float the hammer with a shorter, stiffer spring? Or make an SSG?

Well, orginally I had a short stiff spring. But now, ive got the stock spring back in with preload, a heavy return spring, and a .029 jet and its actually working better. Easier to tune the valve. This is a learning curve for me thats for sure lol.

 

[vmaxpro]

What was fun was a heavy return spring, free floating hammer and a .062 jet. Full machine gun lol

 

[vmaxpro]

Some more fun results. Using a short heavy ( from talon tunes) taipan spring with delrin spacers to tune the gap for now, and a .034 jet with no spring preload shows im getting closer. The heavy valve return spring seems to be a must. At 150 bar Im getting 990 fps with 93gr slugs and its just sipping air and is much quieter. I took 10 shots above the reg from 200 bar and had more to go. Pretty cool!

 

[vmaxpro]

So it seems the smaller jetting, the more lift and dwell but there is diminishing returns. The larger wants to close the valve too fast unless a heavy hammer spring is used. But, by using a large jet and no return spring gets the valve hard to tune and wastes air.

 

[vmaxpro]

Well, dont want to give any false hope here, looks my chrono went bad giving me false numbers. Got another one out and got some real number. 990 @ 150 bar with 81gr jsb. Still not bad! Easy to cock, and more shots than factory. Still got some work to do!

 

[mtnGhost]

Well, dont want to give any false hope here, looks my chrono went bad giving me false numbers. Got another one out and got some real number. 990 @ 150 bar with 81gr jsb. Still not bad! Easy to cock, and more shots than factory. Still got some work to do!

A good Doppler / LabRadar pays for itself in ammo alone for tuning!

 

[vmaxpro]

A good Doppler / LabRadar pays for itself in ammo alone for tuning!

I hear ya! One of these days I’ll get one haha.

So using the “ lofty goal” is pretty darn accurate. I put up a wtb ad for 800mm fx liner. I may not need it, Im so close to my 200fpe mark, 180 may just be good enough!

 

[Pale_Rider]

So it seems the smaller jetting, the more lift and dwell but there is diminishing returns. The larger wants to close the valve too fast unless a heavy hammer spring is used. But, by using a large jet and no return spring gets the valve hard to tune and wastes air.

Is your valve similar to the JSAR balanced valve? I’m asking because theirs had jets too.

Have you tried tuning it by making different size vent holes in the valve stem?

 

[Long_Shot]

That's impressive. This is interesting to me, since I have a .35 cal. Cricket platform that I was wanting more power from.
Look forward to seeing more.

 

[vmaxpro]

Is your valve similar to the JSAR balanced valve? I’m asking because theirs had jets too.

Have you tried tuning it by making different size vent holes in the valve stem?

Yep! The jet is located on the back of the small end of the poppet.

 

[Pale_Rider]

Any issues with the first shot being slower?

 

[vmaxpro]

Any issues with the first shot being slower?

With no valve spring It was a little lower on first shot, maybe 20 fps. Now with a strong return spring I dont see any drop at all.

 

[mtnGhost]

I hear ya! One of these days I’ll get one haha.

So using the “ lofty goal” is pretty darn accurate. I put up a wtb ad for 800mm fx liner. I may not need it, Im so close to my 200fpe mark, 180 may just be good enough!

I would keep the barrel as short as possible and scale the power with air pressure. An 800mm FX liner is going to introduce a whole new world of problems that defeat the pupose, if you know what I mean.

Now if you can setup a barrel to run .358 ammo nice and tight, that would also help increase velocity. For pressure, I would think 215bar minimum for 125gr, but that might not be the right / safe platform for pressure that high.