.22 Cricket mini Carbine Power Tune

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Another question I have for the experts is the hammer spring and hammer. 

1. Do you use the stock hammer for the power tune? If not what is recommended?

2. The hammer spring obviously needs to be heavier. Any suggestions? Ernest sent me 3 hammer springs plus one valve spring to use. I think I have the correct longer lighter valve spring but not sure which hammer spring to try first?

Thanks for all the advice, appreciate it.

Mike 
 
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I'd personally increase hammer weight by the % of power your intend to increase, but its not required. You can add weight to the stock hammer normally by using thick washers that fit either inside the hammer or outside on the back provided neither interfere with clearance. That would allow you to use the same hammer spring the rifle currently has. JMO.



If you can't slightly modify hammer weight and require a heavier rated spring the same % of power increase but divided in half should suffice. So if you currently have 10 lb/in and are increasing power by 20% then you'd want to run 11 lb/in provided the 10 lb/in isn't getting you there. You should know best if your current spring is maxing out near the plateau or if there is enough room left in it to leave it all unchanged and just add more preload. I don't know if crickets have hammer preload adjustments that are pre-set or user adjustable or not at all.



-Matt
 
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Mike, Fuss’s power tuned .22 Cricket is using a .25 Cricket HS and no added weight. His reg is at 150 bar and I installed a lighter valve-return spring. I tuned a converted to .30 Cricket that needed an added hammer weight but it was set to 162 bar. 

I’d hope you can install a .25 HS, the light valve-return spring and set reg at 155 bar and get what you are looking for. Although, Matt had a good suggestion about adding some washers for weight which would preload the HS as well.


 
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Thanks again Matt and Derek. For those interested, I'm waiting on the Huma to get here. I also called Mark @crank who also lives here in San Diego and has LOTS of experience with machining and gunsmithing in general. He's currently busy this week and weekend, but volunteered to help out the next week. I won't have the reg till then anyway, so I'll take the barrel, action and valve over to his place then and we'll do the porting and polishing. After that I'll install the Huma nd Power Plenum and start the tuning process with the valve and hammer springs, and maybe a hammer weight. 

Its pretty cool that this is turning into an AGN group effort. ;) More to follow...
 
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Update on the project. As you know from previous posts, I wanted to do this project for two reasons. First is that it looked very interesting and I hadn't seen it done before (although I know Ernest did some .30 cal Mini Carbines) to shoot the .22 cal RD Monster 25.4 grain at 42-ish FPE. Second, my best shooting buddy Nick @socaloldman is looking for a small-ish, lightweight, super accurate woods walker type gun that isn't pellet fussy (like the FX Wildcat Compact). So, basically same size and weight as FX Warcat, shooting 42 to 45 FPE, and getting about 35 (or more) shots per fill. 

Well, that gun at the time was/is the .22 Cricket mini Carbine.

Herein lies the rub. I just bought that .22 Taipan Mutant Standard that was on the AGN Classifieds. And that one would also be a prime candidate since its small, accurate (CZ barrel), awesome trigger, etc. Plus larger pressure tube and barrel is about four inches longer than the mini. I don't know if the pressure tube is the same diameter as the Cricket, so not sure about adding a power plenum. Will check that this weekend.

Just FYI, why am I buying all these guns lately? Answer is the Horse Ranchers at the permissions I shoot now all want an accurate air rifle for their ground squirrel problems. I have about 100 acres of permissions in Descanso, CA, east of San Diego. So, since July I've bought and sold 7 air rifles, two .22 Daystate Renegades (one was mine for a long time and highly modified, that’s the gun I almost always shot over 720 with in 25M BR, and should have kept), one .22 FX Bobcat, one .22 Cricket bull pup, one .25 Cricket bull pup, one .22 FX Wildcat, and now Nick's .22 FX Streamline. I have two more not sold, a .22 Cricket mini Carbine and a .22 Taipan Mutant standard. I'm not keeping them in case you were wondering.

So my dilemma is which one to "power tune". What we're going to do is scope both of them, and Nick will take them and shoot both for a week or two. Whichever one he likes best we'll power tune as described above. Might be a few weeks until I make the decision. The other one will be sold.
 
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Hello all, I finally figured out how to log into this site.

I wanted to get on this thread because there is some erroneous information being handed out here.

Centercut, if you add any weight to the striker or change the striker to a heavier one you will damage the internals of your Cricket receiver to where it cannot be repaired. Also if you go with anything other than a Cricket hammerspring, either .22 or .25 you will end up with the same terminal damage to your receiver.

I say this because I have seen receivers that had the added weights or stronger springs added to them, which ended up requiring a total receiver replacement.

Also, taking you reg setting to 150 bar is way more than necessary.

When I have everything in place when I am doing a powertune, my reg setting is only slightly higher than factory.

Intenseaty just picked up his mini carbine, without adding a plenum extension, I was able to get it to shoot the JSB or Air Arms 18 grain at 905 fps with only a slightly higher reg pressure but also doing all my other trickery to the internals.

Please don't add weight or go to a stronger hammerspring.

Take care.



Charlie Frear, Georgia Airguns
 
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C'cut isn't aiming at shooting the 18gr. He wants to shoot the 25gr RD Monsters at 860+ fps. He is absolutely going to have to up the reg pressure near 150 bar to do so along with other mods discussed. He's planning to use a Cricket HS from what I understand.

Charlie, you do a great tune and provide great customer service. There is a wrong way to do things but in all due respect, there is also more than one way to skin a cat..........
 
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Thanks much Charlie, appreciate the input. I have the metal HST adjuster, and will start with the stock Hammer Spring. Like I said above, if I can get to a "knee" of between 830 and 850 FPS, I'll be happy, but would be happier with 860 to 875 FPS. Depends on accuracy and shot count. I also have the additional plenum I bought from Ernest, and with that he sent a lighter longer valve spring and three hammer springs. I'm pretty sure one is from the .25 Cricket, not sure about the other two. I certainly don't want to damage anything internal to the receiver, that's for sure. The forum has been great in providing suggestions and recommendations, and I truly appreciate everyone's expertise and opinion on how to get this done...

It could turn out to be a moot point if Nick decides he likes the .22 Mutant better than the Cricket mini. He's going to shoot both over the next couple of weeks and decide. Both have their plusses and minuses. Very similar guns in reality. With either one, like I said, will be ports enlarged and polished, port edges chamfered and rounded, plenum added, and reg. pressure increased. If the stock .22 spring is enough, great. If not, then I'll try the .25 spring. That in combination with the lighter valve spring should get me on the path I want to go. Its not like I don't thoroughly understand stress calculations and flow dynamics, etc. since my expertise and education are in Nuclear Engineering.
 
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Derek, the main point of my post was to inform all airgunners as to what can happen when you use heavier strikers and stronger springs.

Something I did not mention, the main limiting factor of obtaining power from a PCP is barrel length. Now I have not explored a plenum extension or super high reg settings on a Mini Carbine, so I am going to say with my experience there is very little more power to be gained from the given barrel length of the Mini Carbine. On intensity's .22 Mini Carbine I upped the reg pressure to where I believe the most could be gained along with all my other trickery to the internals. His gun on a 255 bar fill was still getting about 38 to 40 shots, going with such a high reg pressure will drastically cut down on shot count.

I hope it works out well for Centercut, I look forward to his results.

I e-mailed Kalibrgun Cricket last night and they told me the .25 Mini Carbine does not exist, it is only made in .22 or .177.

Thanks



Charlie Frear, Georgia Airguns
 
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Charlie, they (Cricket) must respond to your e-mails. I have e-mailed them and all I wanted to know was the barrel breech o-ring size for a .25 Cricket, since on the drawings on their web site all they list is .22 cal. breech o-ring size. No response after two e-mails about a week apart two weeks ago... ;(

PS., I hear you about barrel length, and am tending to agree that even though I think I can get 850 FPS with the .22 RD Monsters, I may only get 15 to 20 shots per fill, and that isn't acceptable. Worst case is that I port/polish, get unacceptable results on shot count (or velocity), and go back to normal plenum and sprint set up, but have 900 fps with 18s vice 850 fps which is the stock power (at least on the two that I have that is about the stock FPS). So not a bad thing. 

Should that be the case, I'm very confident I can get the velocity and shot count and velocity I want from the Mutant. Barrel is 19 inches, pressure tube is larger, etc. Yes, I know you used to sell and tune Mutants, so let us know your thoughts on that? Different set up with the way the transfer port is located in the receiver, but other than that not much different...? 




 
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You can't magically obtain the power Centercut is after without increasing reg pressure, and adding more hammer energy by means of additional weight or spring . Of course increasing barrel length would be the most optimal situation. I can't speak in terms of potential internal damage when slightly increasing hammer energy but I do know my math stands firmly correct when applied to his current barrel length. Increasing hammer weight marginally by 20% or so should not cause serious irreparable damage...and if it does I would want whatever was damaged to be reinforced / re-done...you don't want such fine margins anyhow...
 
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Centercut, I did very little to the Mutants as far as any tuning and power modding, I was not able to spend enough time with them before my supply was cut off.

Ackuric, I don't want to rain on your party but I have tuned a lot of these Crickets, I have my tricks on how to get the power I do without adding weight to the striker or a non factory spring while still keeping the reg pressure setting very close to factory. In my rather well traveled opinion, I would say any added weight will eventually result in the terminal damage I have seen done to Cricket receivers. 

Thanks

Charlie Frear, Georgia Airguns
 
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