Generally, in a regulated PCP, as you increase the FPE requirement, you need a higher setpoint pressure, or the efficiency suffers.... even if you can attain the higher FPE level.... This means that the typical trade off in FPE and shot count you see in an unregulated PCP doesn't often apply.... As you increase the setpoint pressure to achieve the higher FPE, you lose "headroom", ie the amount of HPA available between your fill pressure and setpoint, and that costs you directly on shot count.... For instance, if you increase the setpoint from 1800 psi to 2200, on a gun with a 3000 psi fill, the headroom in the HP side of the regulator decreases from 1200 psi to 800 psi, which relates to a direct 33% loss in the air available to produce shots.... Factor in that your shots are now more powerful, and each one requires more air, and the shot count drops dramatically, even if the efficiency remains the same.... If you don't increase the plenum size, you are likely to lose efficiency at the increased FPE level, further reducing shot count.... and if you do increase the plenum size, you lose even more air on the HP side, which again loses the ability to produce shots.... In a nutshell, that is the basic reason that regulated PCPs are more suitable for low to medium power applications.... The exception is if they are specifically designed, from the ground up, for a high-power application.... with a large bottle and a large plenum.... Bob
40 FPE is not a high-powered tune for a .25 cal.... With equal barrel length and pressures, and similar proportions on the ports (eg. 75% of caliber, for example), the following tunes are roughly equivalent.....177 cal.... 20 FPE.22 cal.... 30 FPE.25 cal.... 40 FPE.30 cal.... 60 FPE.35 cal.... 80 FPEThe above power levels are quite reasonable to achieve with a regulated PCP and still get a good shot count and efficiency.... At 1.5 times those FPE levels, things get more difficult with a regulator, and you have to start thinking about longer barrels, bigger ports and plenums, and maybe higher setponts.... To get twice those FPE numbers, you are really pushing what can be achieved with a regulated PCP, and you will be looking at bullets to get the FPE and bottle guns to get the shot count.... In most cases, starting with a conventional, single tube PCP, you would be better off unregulated....Bob
I broke down and bought a TSS for my regulated Mrod im thinking im going to be able to get a higher power tune than my last and looking forward to the easier cocking for sure!
Quote from: Dairyboy on January 05, 2017, 11:21:13 PMI broke down and bought a TSS for my regulated Mrod im thinking im going to be able to get a higher power tune than my last and looking forward to the easier cocking for sure!Great, but how did you manage it? I didn't think they were available quite yet. Not on the web site, yet, that I could see. In any event, I will be looking forward to your results. Good luck.
Well, it is easier to get 40 FPE in .25 cal than in .22 cal, because the air has more area to push on.... To get 40 FPE in .22 cal is going to be similar to trying to get about 53 FPE in a .25 cal in terms of efficiency.... but you only need enough air (at that efficiency) to develop 40 FPE, not 53 FPE.... Shorty got 24 shots with his 50 FPE tune in .25 cal, so at the same pressure you might get 30-32 shots in .22 cal.... I think three mags at 40 FPE should be easy, but four 10-shot mags at 40 FPE in .22 cal might be pretty tough with a regulated MRod....Bob
It is highly unlikely you will get 30 shots at 40 FPE with your .22 cal. The main thing to focus on is the accuracy and finding the most accurate pellet for your unique barrel. The speed at which you push a pellet will be part of the accuracy equation. I have pushed the 21.14gn to 35 FPE once, but the accuracy and shot count were reduced at that level. However, this was with a stock valve and porting so I suppose you could hit 40 FPE at the peak with a modified valve and heavy lead, but not for 30 shots unless you fill to levels beyond the manufacture's safe operating recommendations. I run 40 shots at 30 FPE at a 2% ES for accuracy at 50 yards and beyond, but that's just me and what I like my .22 to do.
Terry I've seen where guys are using the .25 Mrod valve in their .22 also, I've never really looked into it but it's worth finding out about.
40 shots at 30 FPE will be easier to obtain than 30 shots at 40 FPE in .22 cal.... To get 40 FPE you will probably need larger ports than stock, in a regulated MRod....Bob
Quote from: Wayne52 on January 06, 2017, 10:53:52 AMTerry I've seen where guys are using the .25 Mrod valve in their .22 also, I've never really looked into it but it's worth finding out about.On Gen II, the main difference is the poppet spring. The 25 cal TP has a larger ID than the 177/22 TP. ie the valve itself won't buy any real performance improvement. Tim's valve that he has ordered will be much better than stock.
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