a ? about Short power
Is it common that a Short shoots at 30fpe? I’ve got a Petr Short and with the hammer recessed to o.o35″ it’s producing that kind of power with AA 18 grain pellets, along with a low Sd (3.52). It just seems to be shooting very hot. The gun can reach over 900 fps with no problem. That’s a problem for me.
thanks
Darryl
All Replies
146 bar which is the factory setting, a while back I just rebuilt the reg to change out the 2 small 0-rings to Polyurethane ones Dman sent.
Thing for me is and you may also consider ….
On my Cricket 177 when I did the barrel turn to reduce velocity it was a bit of a pain if I wanted full power again for some reason(s).
Although much easier than to pull and reset the reg.
I returned the barrel and just use the HST to QUICKLY on the fly dial the gun anywhere between 8 – 20 fpe !
You could also just pull the reg out and leave/don’t touch the setting and just change the 2 O-rings and see how much it improves, no reg tester needed for that.
Also no need to dissemble the entire gun …….
Just degas the AT, remove the receiver, remove the rear cap, pull the reg, remove the C-clip, remove the piston and replace the 2 O-rings.
Some Voodoo if you like, I lightly polished the piston shaft too. :biggrinn:
…. right after the rebuild.
~ Greg
Greg, that’s impressive! What did you say your reg is set at? It shows I may be able to take the power level down even further than I assume. If accuracy is the main thing, then perhaps I’m off mission in also going for lowert Es and Sd values?
thanks for posting this string. It’s something to mull over as I go forward.
Darryl
Darryl,
Thing is with a SD = 6 and ES = 20 @ a 30 yards shooting distance that’s only a .04″ shot to shot and a .2″ total vertical difference.
~ Greg
Ernest Quotes about the Mutant per Endo:
“This thing put the Edgun and Cricket in the back Seat.”
“All the negative things I know about the Edguns and Crickets you don’t see on the Mutant.”
“All the positive things I see on the Mutant I don’t see them on the Edguns or Crickets.”
He also said from one of his posts, but I haven’t try it:
“There is a spring guided on the end of the hammer that slide in the brass short spring guided on the HSTA so the spring stay straight while compressed. on the good note there is no hammer spring preload on the valve stem around 800fps and below —that’s why the speed can be adjusted down to ZERO.”
~ Greg
Greg, I do know that the HST can be backed out far enough to where the gun won’t cock (same thing if you turn it in too far too). But I’ve backed the HST out far enough to where there is so little air release that only the lightest puff can be felt against the hand. So being adjusted down to zero is 100% doable, from my own experience.
In my HST tuning efforts, it’s a thin line between being on the mark, and going just a hair too far one way or the other of the target goal (low Sd at 18 fpe). I suspect I’d have to get a slightly softer spring, as the OEM one is quite stout. Unless!! Unless someone is aware of the Short being tuned to less than 18 fpe with the OEM hammer spring?
Darryl
Hoot: where have u been …. good to see u back !
Ernest Quotes about the Mutant per Endo:
“This thing put the Edgun and Cricket in the back Seat.”
“All the negative things I know about the Edguns and Crickets you don’t see on the Mutant.”
“All the positive things I see on the Mutant I don’t see them on the Edguns or Crickets.”
He also said from one of his posts, but I haven’t try it:
“There is a spring guided on the end of the hammer that slide in the brass short spring guided on the HSTA so the spring stay straight while compressed. on the good note there is no hammer spring preload on the valve stem around 800fps and below —that’s why the speed can be adjusted down to ZERO.”
~ Greg
Hello Mike,
Even while I’m exploring this low-power sweet spot, I intend to open the air tube up and have at the regulator, if only to take advantage of Greg’s good grace and generosity in providing me with an o-ring upgrade kit. Also, Endo has offered me the use of his regulator tester, so I at least will be able to log it’s pressure setting. Who knows? maybe i’ll be able to get the gun shooting in fine tune at lower than 18 fpe. I do own a non-FAC, non-regulated PCP, which is becoming quite the closet queen since the Short appeared on the scene. It’s a quirky little thing, but at 11.53 fpe, it’s up to easily dispatching local pests, and has a nice feature for very quick follow-on shots (not that I ever need them. :whistle: )
See here: https://www.youtube.com/watch?v=tBNYs3ZY4KE&t=98s
Dam Hoots alive,
But I am with him going into the regulator is a little over my skill level. Greg is the man when it comes to understanding the PCP and working on the Mutants , Me I am all about power,But accuracy above all else,
I wonder if any of them guys in the UK have any Mutants in the 12 ft LB range and how they did it?
Just a thought ,
Mike
Hoot, I think I’ve touched a low-power sweet spot with HST tuning. I can get low Sd values with about 18 fpe. Still, I’ll want to open it up and yank the regulator. Btw, yes, touched, but got to looking for a lower Sd, and used a heavy hand instead of finessing it. So now I’m search that sweet spot again. Oh well. Tinker-tinker.
Darryl
:hoot:
Greetings misfits!
If I wanted less power I’d simply back out the hammer spring. That method also has the benefit of saving a lot of air, and would likely cut the muzzle report in half.
Poor ol’ Mike, out there in West Texas, has been snake bit too many times, but his advice is still good. GKU is on top of such things too!
Personally, I don’t like messing with the regulator. I lack the tools (brains) to do lt right. Being half blind doesn’t help either!
However, I’d try the simplist solution first and back out the hammer spring.
My Shorty is at 49 FPE and I’d like 60 but that’s not going to happen.
Regards Kindly ‘Ol Unce Hoot:
Greg, pm sent. Thank you!
Darryl
Hum … Darryl,
IIRC the hi SD and ES on the Mutants comes from not updating the 2 small O-rings on the piston inside the reg.
Typically SD and ES should be about 2.5 and 12 respectively from an entire shot fill.
Dman sent me new ones that are white in color, I believe they’re Silicon .. Teflon or some Urethane shit I don’t remember.
If you like Sir PM me your address and I’ll send you some for free.
~ Greg
Hi Greg,
I get it; give it a try and report back. Sounds good to me. I was just curious about what would be going on with the gun when the barrel port is reduced. Petr’s elongated port is said to cause a minor increase in fps, but maybe, in conjunction with a turned-up regulator, the gun is made into a hot shooter. It will be interesting to see if the reduced fps comes with reduced Es, and Sd. Tuning an unregulated PCP seems simple in comparison, though never the low Sd values of a regulated gun (in harmony with the HST).
So, with the regulator likely above 140 bar (150 bar?) that’s a lot of air released per shot…only to encounter a restricted path at the barrel. I’m trying to imagine what’s going on there. Out of curiosity, of course. :biggrinn: Theories, SWAGs and WAGs welcome! :winkn:
appreciate the direction, Greg.
Darryl
Darryl,
U always ask the harden question(s) …… !
…. the, beaten me. :rofl:
I like to help honestly, with every TAG member with at less 100 posts under their belt if my time permits me to do so.
I never tried to detune my Mutant 22 Shorty, only upturned ……..
BUT,
Try the barrel turn tune to my KG Cricket Compact 177 cal ONLY, U see !
Which had no ill effect in my book, only pluses … the shot count when into the heavens …. + 250 shot count filled to only 200 bar … on the 12 FPE tune in setting.
2 totality DIFFERENT animals if U ask me … Sir ….. so …. U, that is threading in unthreaded territory….. my friend.
… post up your NEW … Shorty findings !
~ Greg, PS. only the others suck dick …….. sorry 
… a DRUNKEN POSTING !
The reg on them are set high usually in the 140+ range, mines is set to 146 bar and achieves a maximum 820 fps with 18g.
If you don’t want to mess with the reg I’d try and reverse what Peter did to the TP enlargement.
By turning/rotating the barrel about 2 hour to start with and blackout the HST, retest to find where it maxs out than back out about 1/4 turn.
If this get you high or low from what you like turn the barrel accordingly to achieve what you desire ……. 15-30 minutes at a time.
Also, before loosening the frame hex bolts, engage the safety !
This is so you don’t loose the frame location/positioning which is a added pain to find/reset.
Most Shorty owners like me want and kill for more fpe ……….
Gee, u don’t like a Prod ? :rofl:
….. JUST JOKING WITH YOU Darryl, it’s been a long time good to see you back !
~ Greg
Hi Greg,
Thanks for the suggestion on turning the barrel. I’ve heard of that from long ago, and not related to the Short. Turning the barrel honestly never occurred to me. It’s a great suggestion, really. Thanks for the tip with the safety too.
My highest average fps was 913 fps, with an Es of32.18 for the 10-shot spread, and an Sd of 15.5 I had not thought these Shorts capable of almost 34 fpe. I’d be happy with half that or even lower.
Oh, I had a Prod some years ago. Even put a Marauder barrel on it. SIlly, actually. It reminded me of a Buntline Special! :biggrinn: Aside from that, it was pretty good as long as I fed it H&N 5.3mm 14.4 domes.
What ill effects, if any by turning the barrel? Not that I won’t try it, but aside from choking off the TP, any back-pressure issues?
thanks again!
Darryl
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Greg,
It hurts my eyes to look at that string! a 6-fps Es over 32 shots and 100 bar usage is quite the feat, and says a lot for the gun and it’s owner. The reg is still at 146 bar?
Thanks for the info on turning the barrel, the voodoo (polishing the valve shaft), and the AT removal. The kit is out for delivery,and I thank you for that too.
I’ll keep this thread informed as I go, but I’m waiting for this heatwave (97 and high humidity forecast) to pass out so I don’t. 😛
Darryl