Contradiction between FX and Pyramid Air

IMHO I see both as valid statements.

As far as how far you can shoot your gun down FX says " you will use the second regulator as your reference point" So don't shoot below 100 bar. What they did not say is "or damage to the gun can occur". Without enough pressure, in the gun, to fight against the hammer and return spring your valve will get pounded pretty hard and damage can, or will eventually, occur.

Your settings are good and as Pyramyd air said " In order to get the best performance you would want to keep the pressure in the tank above the first regulator pressure". So fill before 130bar because when you shoot to near the regulated pressure variances in speed, that affect accuracy, can and often do occur. 



Following both statements will keep you from going below the pressure from either one of the regulators and will allow you to get the best performance out of your gun without damaging it. 

I can't see how it would make a difference.... the pressure difference between the two regulators is so minimal, I can't imagine how falling off the primary regulator would affect performance until you fell off the secondary regulator, too.

So, essentially, I am thinking it's the same as with all regulated guns. Once charge pressure falls below it's regulated level, you will have power drop off and poi shift then, or shortly there-after 

Ha, what do you know, (inside joke) I agree with the biohazardman.



Mike

Once you have had a sesión of 50 shots, refill your rifle to top pressure, irrespective how much pressure it still have. 

You assure your rifle is ready for a long shooting sesión again. 

If you’re shooting pellets, reference the second reg. If shooting slugs, base your refill off the first reg.

If you’re shooting pellets, reference the second reg. If shooting slugs, base your refill off the first reg.

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Doesn't matter if you're shooting slugs or pellets, the rifle and regulators function the same regardless of the shape of the lump of lead in the barrel.

The second regulator controls the plenum pressure, and consistent plenum pressure is what matters for shot to shot velocity consistency. Shoot down to just above the second regulator set point, then refill.

The first regulator is only there to knock down the bottle pressure to a level closer to the second regulator setpoint, so the first regulator does most of the work of reducing bottle pressure and the second regulator now works with a smaller change in pressure across it for better consistency.

I can shoot my slug tuned M3 down right to the second regulator setpoint before the velocity changes and point of impact starts to change.

Shooting the rifle below the second regulator setpoint can be harder on the valve because there is now lower than normal plenum pressure trying to keep the valve shut, so the valve slams open harder than usual when shooting below the second regulator set point.

My recovery time slows when I get below the first regs set point. If I don’t wait and watch my second gauge, I can fire subsequent shots at a lower bar and not be on my accuracy node. My groups show it. Pellets don’t care. 

My recovery time slows when I get below the first regs set point. If I don’t wait and watch my second gauge, I can fire subsequent shots at a lower bar and not be on my accuracy node. My groups show it. Pellets don’t care.

Click to expand...

Waiting slightly longer between shots as the bottle pressure drops below the 1st regulator setpoint and approaches the second regulator set point allows the plenum to completely refill and avoids the issue you described.

When the bottle pressure is below the first reg set point, the 1st regulator is now open and the plenum fill rate is now a function of the orifice sizes in the 1st and 2nd regulator and the pressure delta between the bottle pressure and the 2nd reg set point... So the plenum fill rate will slow as the bottle pressure approaches the 2nd reg set point as the air has to pass through 2 very small orifices to refill the plenum, and the smaller delta p means a reduced flow rate between the bottle and plenum.

If you set the 1st reg only about 15 bar above the 2nd reg set point, the plenum refill time is slower but the plenum refill time stays much more consistent from a full bottle to nearly empty as the rifle won't fall off the 1st regulator until near the end of the fill. Compare this to a setup where the 1st reg is set say 40-50 bar higher than the 2nd reg; with this setup it will refill the plenum faster as long as the bottle pressure is above the 1st reg setpoint, but once the bottle pressure drops under the 1st reg setpoint the plenum will refill progressively slower until you shoot down to the 2nd reg setpoint.

This is a drawback of the 2 regulator design and the large plenum on the M3, the plenum refill rate is slower than a single regulator design because the air now has to flow though 2 tiny regulator orifices to get to the plenum instead of just one, and with the plenum being relatively large it takes a noticable time to fill-- sometimes longer than you're willing or able to wait before sending a follow-up shot.

I have my 1st reg set 15-20 bar above the second regulator setpoint and have no issues shooting slugs from a 250 bar fill all the way down to the 2nd regulator setpoint of 135 bar... But you do have to be aware of the plenum refill time. It's very easy to shoot faster than the plenum will refill, and while that's not a big issue at close ranges it certainly is a problem at longer ranges-- both with slugs and pellets.

My recovery time slows when I get below the first regs set point. If I don’t wait and watch my second gauge, I can fire subsequent shots at a lower bar and not be on my accuracy node. My groups show it. Pellets don’t care.

Click to expand...

Waiting slightly longer between shots as the bottle pressure drops below the 1st regulator setpoint and approaches the second regulator set point allows the plenum to completely refill and avoids the issue you described.

When the bottle pressure is below the first reg set point, the 1st regulator is now open and the plenum fill rate is now a function of the orifice sizes in the 1st and 2nd regulator and the pressure delta between the bottle pressure and the 2nd reg set point... So the plenum fill rate will slow as the bottle pressure approaches the 2nd reg set point as the air has to pass through 2 very small orifices to refill the plenum, and the smaller delta p means a reduced flow rate between the bottle and plenum.

If you set the 1st reg only about 15 bar above the 2nd reg set point, the plenum refill time is slower but the plenum refill time stays much more consistent from a full bottle to nearly empty as the rifle won't fall off the 1st regulator until near the end of the fill. Compare this to a setup where the 1st reg is set say 40-50 bar higher than the 2nd reg; with this setup it will refill the plenum faster as long as the bottle pressure is above the 1st reg setpoint, but once the bottle pressure drops under the 1st reg setpoint the plenum will refill progressively slower until you shoot down to the 2nd reg setpoint.

This is a drawback of the 2 regulator design and the large plenum on the M3, the plenum refill rate is slower than a single regulator design because the air now has to flow though 2 tiny regulator orifices to get to the plenum instead of just one, and with the plenum being relatively large it takes a noticable time to fill-- sometimes longer than you're willing or able to wait before sending a follow-up shot.

I have my 1st reg set 15-20 bar above the second regulator setpoint and have no issues shooting slugs from a 250 bar fill all the way down to the 2nd regulator setpoint of 135 bar... But you do have to be aware of the plenum refill time. It's very easy to shoot faster than the plenum will refill, and while that's not a big issue at close ranges it certainly is a problem at longer ranges-- both with slugs and pellets.

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You were preaching to the choir directing that info at me but it is very good that you took the time to explain it. I’m too lazy sometimes to keep repeating myself on all the topics that have been beaten to death. This one hasn’t so I applaud you. I have two regs on a MKII PP. I can only imagine the time it takes to fill the larger M3 plenum. I have settled on a 30b difference between my regs. It’s the best balance I could find.

You were preaching to the choir directing that info at me but it is very good that you took the time to explain it. I’m too lazy sometimes to keep repeating myself on all the topics that have been beaten to death. This one hasn’t so I applaud you. I have two regs on a MKII PP. I can only imagine the time it takes to fill the larger M3 plenum. I have settled on a 30b difference between my regs. It’s the best balance I could find.

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On my slug tune I'd say it takes about 3 seconds to refill the plenum after every shot based on what I can hear... if things are quiet you can hear the plenum refilling since it's right under your ear. If you take a quick second shot while the plenum is still refilling the velocity and point of impact is certainly different.

On my 25.4gr pellet tune I'd say it takes 2 seconds to refill the plenum after a shot, because with the pellet tune the 2nd regulator pressure is the same as the slug tune but the hammer tension is reduced-- so the valve is opened less distance for a shorter time and uses less air than the slug tune, so there's less volume & pressure loss in the plenum to refill after a shot.

On the 18.1gr pellet tune I'd say it takes only about 1 second to fully refill the plenum, because it's at an even lower hammer spring tension and muzzle energy and uses even less air.

If you have a very "air thirsty" tune on your M3 (high muzzle energy with heavy slugs) then more air from the plenum will be used per shot and it will take even longer to fully refill the plenum, so for maximum consistency and accuracy you have to pace your shooting and wait to shoot until the plenum is fully refilled.

On my Edgun R5M, you can also hear the plenum refilling after a shot-- and even with the larger Huma power plenum I have installed I'd say it only takes about 1 second for the plenum pressure to recover in the R5M. It recovers much, much faster than the M3, and rapidly shooting over a chronograph backs it up.

Be interesting to screw a 1/8 BSPP threaded pressure transducer into the 2nd regulator gauge port on the M3 and do some data acquisition to see how long it takes for the plenum to refill at say a 15, 30, and 45 bar setpoint delta between the first and second regulator pressures to see how the pressure delta between 1st and 2nd regulator setpoints affects the plenum refill time. Also, I'd want to log the full shot strings from 250 bar all the way down to the second regulator setpoint at all 3 1st/2nd reg splits to see how the plenum refill time is affected by bottle pressure. I'll have to see if we have a 1/8 BSPP pressure transducer in the test lab at work, and maybe I can borrow the transducer and the DAQ laptop and do some testing. It's kind of a silly test to do when all it's going to prove is "wait a couple seconds between shots"-- but it would be good info to have.

My recovery time slows when I get below the first regs set point. If I don’t wait and watch my second gauge, I can fire subsequent shots at a lower bar and not be on my accuracy node. My groups show it. Pellets don’t care.

Click to expand...

Waiting slightly longer between shots as the bottle pressure drops below the 1st regulator setpoint and approaches the second regulator set point allows the plenum to completely refill and avoids the issue you described.

When the bottle pressure is below the first reg set point, the 1st regulator is now open and the plenum fill rate is now a function of the orifice sizes in the 1st and 2nd regulator and the pressure delta between the bottle pressure and the 2nd reg set point... So the plenum fill rate will slow as the bottle pressure approaches the 2nd reg set point as the air has to pass through 2 very small orifices to refill the plenum, and the smaller delta p means a reduced flow rate between the bottle and plenum.

If you set the 1st reg only about 15 bar above the 2nd reg set point, the plenum refill time is slower but the plenum refill time stays much more consistent from a full bottle to nearly empty as the rifle won't fall off the 1st regulator until near the end of the fill. Compare this to a setup where the 1st reg is set say 40-50 bar higher than the 2nd reg; with this setup it will refill the plenum faster as long as the bottle pressure is above the 1st reg setpoint, but once the bottle pressure drops under the 1st reg setpoint the plenum will refill progressively slower until you shoot down to the 2nd reg setpoint.

This is a drawback of the 2 regulator design and the large plenum on the M3, the plenum refill rate is slower than a single regulator design because the air now has to flow though 2 tiny regulator orifices to get to the plenum instead of just one, and with the plenum being relatively large it takes a noticable time to fill-- sometimes longer than you're willing or able to wait before sending a follow-up shot.

I have my 1st reg set 15-20 bar above the second regulator setpoint and have no issues shooting slugs from a 250 bar fill all the way down to the 2nd regulator setpoint of 135 bar... But you do have to be aware of the plenum refill time. It's very easy to shoot faster than the plenum will refill, and while that's not a big issue at close ranges it certainly is a problem at longer ranges-- both with slugs and pellets.

Click to expand...

There is some understandable reasoning here but it doesn’t fully hold true. The plenum in between the two regulators is so small that as soon as the second regulator opens up the pressure drops to practically the same value and only starts to gain a difference again when the main plenum is almost filled. With this very tiny plenum in between the two regs I noticed it is advantageous to have the pressure way up high to ensure that the regulators open up after a shot and put as much air as possible into the 72cc plenum without the flow restriction of two regulators. While running at a very small difference I’ve seen instabilities in the regs because they weren’t opened up properly.

With the maverick this second reg makes sense since there is a big plenum in between the two regs. There you can calculate how much higher your first reg needs to be compared to the first to ensure a quick response after a shot. With this super tiny plenum in the M3 the added value is really minimal and cripples the refill time unless you replace the pressure gauge of the first reg for a bigger plenum which is capable of topping up the 72cc plenum on its own. With no bigger plenum in between the two regs the refill rate is always dependent on the two regs at the same time which means two places where flow is reduced.

If you want to do speed shooting I would advice the Impact MKII, it is less restricted in fill rate because of its single regulator.

Click to expand...

There is some understandable reasoning here but it doesn’t fully hold true. The plenum in between the two regulators is so small that as soon as the second regulator opens up the pressure drops to practically the same value and only starts to gain a difference again when the main plenum is almost filled. With this very tiny plenum in between the two regs I noticed it is advantageous to have the pressure way up high to ensure that the regulators open up after a shot and put as much air as possible into the 72cc plenum without the flow restriction of two regulators. While running at a very small difference I’ve seen instabilities in the regs because they weren’t opened up properly.

With the maverick this second reg makes sense since there is a big plenum in between the two regs. There you can calculate how much higher your first reg needs to be compared to the first to ensure a quick response after a shot. With this super tiny plenum in the M3 the added value is really minimal and cripples the refill time unless you replace the pressure gauge of the first reg for a bigger plenum which is capable of topping up the 72cc plenum on its own. With no bigger plenum in between the two regs the refill rate is always dependent on the two regs at the same time which means two places where flow is reduced.

If you want to do speed shooting I would advice the Impact MKII, it is less restricted in fill rate because of its single regulator.

Click to expand...

I'd agree, there's practically no plenum volume between the 1st reg and 2nd reg on the M3 other than a few small air passages in the lower action block, and on every shot both regulators will open and feed air since there isn't a large plenum space after the 1st regulator for the 2nd regulator and main plenum to draw from. Thus the air has to flow though 2 tiny regulator orifices after every shot and main plenum refill time suffers. Adding an external plenum to the 1st reg gauge port to add air volume between the 1st and 2nd regulators would be an interesting experiment.

Having the setpoints a bit wider between the 1st and 2nd reg would allow a tiny bit more of an air reserve for the main plenum to pull from after a shot, as well as keeping the opening and closing points between the 1st and 2nd reg a bit more independent-- but as I mentioned earlier it does cause a larger variation in main plenum refill time as the bottle pressure drops under the 1st regulator setpoint. That may or may not be an issue for you depending on the speed you shoot. You are right about regulator consistency as having the 1st reg setpoint too close to the 2nd reg setpoint can result in variation in the main plenum pressure as both regulators require a certain amount of pressure delta across the piston for them to function consistently and seal properly and overcome any stiction/friction. My second regulator seems very happy with a 20-25 bar split between the 1st and 2nd regulator setpoints which keeps the main plenum refill time quite consistent over an entire session starting from a full fill down to just above the 2nd regulator setpoint, but if your 2nd regulator is a bit "sticky" a 20 bar drop across it may not be enough to fully overcome piston/o-ring stiction and lead to inconsistent main plenum pressures. In that case increasing the 1st reg setpoint so the 2nd reg has a larger pressure drop across it could certainly produce more consistent regulator function/sealing and more consistent main plenum pressure.

IMO, the proper fix for this situation is to rebuild and relube the sticky regulator so it functions smoothly... but increasing the 1st regulator setpoint to produce a larger pressure delta across the 2nd regulator and make it function and seal more consistently works too, but at the expense of a larger change in main plenum refill time over a session as bottle pressure drops.

When I first got my M3, the first reg was “sticky” and when set at 165-170 bar (2nd reg at 135 bar) I could often take 2-3 shots and watch as the first regulator gauge would drop after every shot all the way down to about 137-140 bar-- only then would it fully reopen and return to 165-170 bar, then the cycle would repeat. The main plenum always stayed at 135 bar and the chronograph showed consistent velocity, but when the 1st reg was "sticking" and low on pressure the main plenum would take much longer to refill. If you waited about 3-4 seconds between shots the chronograph and target never showed a difference even though the first regulator was a bit lazy.

After disassembling the 1st regulator, cleaning, a bit of minor polishing on the belleville washers, and relubing, the 1st reg pressure now consistently drops about 10 bar after every shot but immediately refills to 155-160 bar which is the current setpoint. Main plenum refill time over an entire fill is more consistent as a result.

I also agree that if you're going to speed shoot and want the absolute fastest main plenum refill time for the most consistent followup shots I would either set the 1st regulator very high (say 200+ bar) or probably even better yet, remove the 1st regulator piston, belleville washers, and adjuster screw entirely so the rifle is only running on the second regulator and the air only has to flow though one tiny regulator orifice instead of two. At this point it's basically a Mk2 with the quick tune hammer spring setup and a few other improvements.

I'd agree, there's practically no plenum volume between the 1st reg and 2nd reg on the M3 other than a few small air passages in the lower action block, and on every shot both regulators will open and feed air since there isn't a large plenum space after the 1st regulator for the 2nd regulator and main plenum to draw from. Thus the air has to flow though 2 tiny regulator orifices after every shot and main plenum refill time suffers. Adding an external plenum to the 1st reg gauge port to add air volume between the 1st and 2nd regulators would be an interesting experiment.

Having the setpoints a bit wider between the 1st and 2nd reg would allow a tiny bit more of an air reserve for the main plenum to pull from after a shot, as well as keeping the opening and closing points between the 1st and 2nd reg a bit more independent-- but as I mentioned earlier it does cause a larger variation in main plenum refill time as the bottle pressure drops under the 1st regulator setpoint. That may or may not be an issue for you depending on the speed you shoot. You are right about regulator consistency as having the 1st reg setpoint too close to the 2nd reg setpoint can result in variation in the main plenum pressure as both regulators require a certain amount of pressure delta across the piston for them to function consistently and seal properly and overcome any stiction/friction. My second regulator seems very happy with a 20-25 bar split between the 1st and 2nd regulator setpoints which keeps the main plenum refill time quite consistent over an entire session starting from a full fill down to just above the 2nd regulator setpoint, but if your 2nd regulator is a bit "sticky" a 20 bar drop across it may not be enough to fully overcome piston/o-ring stiction and lead to inconsistent main plenum pressures. In that case increasing the 1st reg setpoint so the 2nd reg has a larger pressure drop across it could certainly produce more consistent regulator function/sealing and more consistent main plenum pressure.

IMO, the proper fix for this situation is to rebuild and relube the sticky regulator so it functions smoothly... but increasing the 1st regulator setpoint to produce a larger pressure delta across the 2nd regulator and make it function and seal more consistently works too, but at the expense of a larger change in main plenum refill time over a session as bottle pressure drops.

When I first got my M3, the first reg was “sticky” and when set at 165-170 bar (2nd reg at 135 bar) I could often take 2-3 shots and watch as the first regulator gauge would drop after every shot all the way down to about 137-140 bar-- only then would it fully reopen and return to 165-170 bar, then the cycle would repeat. The main plenum always stayed at 135 bar and the chronograph showed consistent velocity, but when the 1st reg was "sticking" and low on pressure the main plenum would take much longer to refill. If you waited about 3-4 seconds between shots the chronograph and target never showed a difference even though the first regulator was a bit lazy.

After disassembling the 1st regulator, cleaning, a bit of minor polishing on the belleville washers, and relubing, the 1st reg pressure now consistently drops about 10 bar after every shot but immediately refills to 155-160 bar which is the current setpoint. Main plenum refill time over an entire fill is more consistent as a result.

I also agree that if you're going to speed shoot and want the absolute fastest main plenum refill time for the most consistent followup shots I would either set the 1st regulator very high (say 200+ bar) or probably even better yet, remove the 1st regulator piston, belleville washers, and adjuster screw entirely so the rifle is only running on the second regulator and the air only has to flow though one tiny regulator orifice instead of two. At this point it's basically a Mk2 with the quick tune hammer spring setup and a few other improvements.

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Regarding the last part: what if I tell you that the chamber where the spring disks are placed is ventilated to the outside world The refill time will become infinite

if you want to have a regulated pressure above 170 bar you need to take apart the first regulator anyway. The standard stack does not accommodate for consistent high reg pressures.