Blatant hijack.... is your R10 more accurate than the S510? How fast is your R10 shooting.
Tuning a regulated gun is trying to find the most efficienct hammer strike without losing power for the pressure your regulator is set at.... The ultimate power will be dictated by the setpoint pressure and the porting in the gun.... Given a set value for those, then you want to try a bunch of preload settings on the hammer spring and plot velocity vs. preload to get a curve like this....You will note that after a given amount of preload, the velocity doesn't increase, all that happens is you waste air and lose shots.... This is on the "plateau" on the left side of the graph.... On the right side, the "downslope", the velocity drops sharply as you reduce hammer strike, the gun gets a lot quieter, and eventually you run into a situation where the velocity INCREASES after the pressure drops below the setpoint of the regulator.... IMO, if you want to shoot at such a low velocity, you need to reduce the setpoint pressure.... Where the two straight lines transition I call the "knee" of the curve, and that is where I tune all my regulated guns.... On that graph, I would use 4-5 turns out on the preload (from coil bind) because I'm getting 95-98% of the possible velocity but using the least amount of air to achieve that, and therefore getting the highest shot count.... Bob
So once I find the hammer pre-load setting that gives me the best efficency and velocity for a given regulator setting the correct way to increase velocity would be turning up the regulator slightly and do the same process with the hammer spring? Obviously I would reach a point where the ports would be the limiting factor but am I understanding the rest of the process correctly?
Then I could shoot till I get a rise in velocity and that would indicate I'm coming off the regulator?
I would try 2 turns in on the preload, just to confirm that you are indeed on the plateau at about 855 fps.... and I would try 2 turns out, to see if the velocity drops even more, to something on the order of 800ish.... You don't need to shoot complete strings to confirm that.... Then it is a matter of simply deciding how much power you need based on the shot count.... You had 41 shots from 840-850 fps in the string above, so if we assume that was from 3200 down to 1800 (1400 psi drop) we can do an efficiency calculation for where you are now if we know the reservoir volume....1400 / 14.5 = 97 bar x reservoir volume = total CI of air used at 1 baraverage FPE = ~29 x 41 = 1189 FPEdivide 1189 FPE by the total CI of air to get the efficiency in FPE/CIIMO, I would not run more preload than you did in the above string, but I would seriously consider 1-2 turns less, you may be shocked at how many shots you gain by doing that.... The final decision will be to strike a balance between FPE and shot count for your purposes.... With only a 12-15 fps drop 1 turn out from where you are, that sounds very promising to me.... It would be like 4.5 turns out on the first graph I posted, which is where I ended up tuning that QB79.... If you absolutely MUST have more power, then you either have to increase the regulator setpoint (less pressure range = fewer shots) or increase the port sizes (with luck, you might just get more FPE with only using slightly more air).... but as you can see, leaning on the hammer spring won't do it....Bob
you forgot to calculate the total CI.... 12.2 CI x 97 bar = 1183 CI1189 / 1183 = 1.00 FPE/CIThat's acceptable, but not stellar.... and exactly what I would expect if you are right at he beginning of the plateau (eg. at 4 turns out on my graph above).... 1 more turn out could easily increase the efficiency by 10%, and combined with the slightly lower FPE (~28 FPE?) could give you 50 good shots.... Bob
Guys, new to PCP entirely but getting an R10 MK2 from BAR (Blackpool Air Rifles) in the UK. It's listed as 'Regulated 200 shots .22cal' which is radically different than what Pyramid here sells that is 40 shots at 990pfs. I know in UK they have FAC rules of no more than 12ft/joules or whatever. Can my regulated one (according to BSA is only 570 ft/s) be adjusted for more power like you guys are experimenting? I won't be tagging squirrel or wild boar but in the event a crow happens to be in my scope I'd want some power behind the pellet! John Bowkett is going to blueprint it but he doesn't correspond via E-mail.
Tuning a regulated gun is trying to find the most efficienct hammer strike without losing power for the pressure your regulator is set at.... The ultimate power will be dictated by the setpoint pressure and the porting in the gun.... Given a set value for those, then you want to try a bunch of preload settings on the hammer spring and plot velocity vs. preload to get a curve like this....You will note that after a given amount of preload, the velocity doesn't increase, all that happens is you waste air and lose shots.... This is on the "plateau" on the left side of the graph.... On the right side, the "downslope", the velocity drops sharply as you reduce hammer strike, the gun gets a lot quieter, and eventually you run into a situation where the velocity INCREASES after the pressure drops below the setpoint of the regulator.... IMO, if you want to shoot at such a low velocity, you need to reduce the setpoint pressure.... Where the two straight lines transition I call the "knee" of the curve, and that is where I tune all my regulated guns.... On that graph, I would use 4-5 turns out on the preload (from coil bind) because I'm getting 95-98% of the possible velocity but using the least amount of air to achieve that, and therefore getting the highest shot count....Bob
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