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
MIke, you may be right. I’d thought about a softer spring as one solution. Endo has been advising me as well. I’ll be performing some specific testing per his instruction, and he’s been very selfless in responding to me. So far, he’s leaning towards my regulator being see on the high side. I gun maxes out at 100 fps higher than his. I’ve seen 928 fps under full HST compression ( just below where the gun won’t cock with too much tension). So maybe a softer spring will allow me to get to the low power I am looking for.
Maybe I’ll PM Greg too.
thanks Mike,
Darryl
Be a lot easier to replace the hammer spring,
Maybe we can get Greg in on his one,
Where is Earnest when you need him.
Mike
hi iride,
Sorry for the scant information. I’d become used to referring to the Mutant Short simply as “the Short”, and yes, it’s a .22.
I’ve been trying to get the gun to shoot efficiently at much lower power levels, as I have no need for 30 fpe. I just had not thought it normal for the gun to shoot at those power levels with the HST turned in only 0.035 in from flush with the action. As I mentioned, it’s a Petr Short (from Top Gun Airguns), though some may not be familiar with that name. The barrel is a “Czech Republic” barrel, not a CZub barrel. I was told by Petr it is made similar to how Lothar Walther barrels are made. Petr angled the barrel transport.
I’ve come to believe the regulator must be set higher than the usual 135~140 bar. At lower power levels, fps the Sd values are very high. Strings averaging between 746 fps, and 756 fps have Sd’s of 11.31 and 12.52 respectively. At an average of 872.9 the Sd is 3.46. So the gun seems more efficient at the higher power level. But it’s the opposite of where I want it. It’s not intended as a range gun, but as a small-pest eliminator, and general backyard plinker. Lower power is where I need it to shoot, and to be most efficient.
I’m guessing I’ll have to face lowering the regulator. I know the hammer spring is “stock” as I’ve compared it to another Short (which happens to shoot with low Sd values at just below 800 fps.The best Sd I’ve seen at less than than 800 fps came at an average of 706 fps (ES of 25.52, Sd of 9.16).
What’s confounding me is the gun shoots very accurately at below 800 fps within 30 yards which is all I have for safe (and quiet)shooting. I’m more interested in being a good neighbor than in 30 fpe.
When I’ve reduced the gun to an average of 676 fps I got this:Es = 39.31, Sd = 12. I’d like to set the gun to be efficient between 15 fpe and 19 fpe. So again, the regulator?
thanks for replying iride,
Darryl
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I guess you are talking about the Mutant, I guess you are talking about the 22,
Accuracy is # 1 for me, But If I was you I would move up to the 25.39 JSB 22 pellets.
Do you know what barrel your gun has ?
Mike
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I remember Peter working on Taipans to get more fpe from the little one …….
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