What happens if you shoot below 125bar with a 250bar rifle?

It will probably risk damaging things, the valve needs the back pressure to work properly and act as a cushion for the hammer striking the valve. Depends on the gun of course.

I disagree. If it is an unregulated gun, your velocity is at least potentially going to be much lower than it is at higher pressure. But I've shot my Prod down to that kind pressure before and it didn't harm it. Depending on the tune the velocity may also be reasonable.

My only regulated rifle I would shoot that low is my P35 in 177. The regulator is set a little above this so I do not do it often but the velocity is not too bad at 100 bar. My bigger calibers have higher regulator settings so their velocity falls off pretty bad so I don't shoot them this low.

It is true that the chamber pressure helps to close the valve on an unregulated gun. It is also true that it's hard to generalize, some guns might really not like it and do something silly like degass themselves. I would only do it if your gun shoots consistent velocities in this pressure range. If it does, I don't see why you cannot go down to where the velocity falls off significantly.

On a regulated gun, the valve is working on the regulated chamber so the pressure in the storage area does not have a direct effect.

With a pcp rifle you really need a chronograph as well. The chrono will tell you what pressure range you should be shooting a particular gun in.

+1
chronograph is an absolute must have.

WHICH gun are you shooting? Regulated or unregulated? If REGULATED shooting below reg pressure could cause problems. Unregulated, not so much. All guns have a "sweet spot" where they shoot most efficiently. If you only fill to the top of the sweet spot & refill at the end of it you'll be doing your gun a favor.

Depending on your hammer setting and the gun but most likely scenario is your speed will go up a few shots and gradually drop lower and lower.

qball said:

Depending on your hammer setting and the gun but most likely scenario is your speed will go up a few shots and gradually drop lower and lower.

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Xactly!

Nothing more should happend.

Some rifles under some preassure the valve does not return and seal, then all air leaks after that last shot.

Nothing else.

Kavliaris said:

What happens if you reach the yellow part of the bar meter? Is the rifle able to shoot under 100bar? I am new to pcps so maybe this question is stupid but I am confused

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WHAT GUN? It matters! Some guns you can shoot to zero pressure and be fine, but some guns are so sensitive that you have to stay in their zone or they get all valve(butt) hurt, like women, some are great, some are drama queens

I don't know the Blitz, but yes the exact mechanism will matter. You can shoot the Leshiy 2 down to very low reg pressure. You probably don't want to go under 10-20 bar, as you risk unseating some o-rings. But you can get pretty low. A Crosman P1322 you can shoot to empty, but it was designed that way, with minimal o-rings.

I am not familiar with those models. My first pcp was a Gladius from Hatsan, it could be dry fired to zero bar/psi, but alas it was not a gun that I liked so it sits in pieces for many years
I am only thinking about gun damage,, as the other have mentioned , shooting below regulator pressure will affect pellet velocity and point of impact

I used to have an Evanix Speed .22 semi-auto that I filled to 250 BAR,

I cut the hammerspring to tune the gun to 20 FPE,

I would shoot the gun down to 80 BAR and get a 220 shots string that would have a very usable curve to 35 yards.


...........Just and example of what can be done with a 250 BAR gun and shoot it under 125

I then re-tuned it to 26 FPE and got 160 shots from 250 BAR to 100 BAR

The simple answer is.....NO. you will NOT hurt, harm, damage your PCP by firing at anything LESS than recommended max pressures.
The pellet or slug will simply travel slower and slower until -- at some point -- it will not have enough 'push' to exit the barrel.
On the other hand--
You definitely can and probably WILL cause issues, problems and damage if you fire ABOVE the recommended max pressures.
But...that's a different topic.

I was not thinking of an Edgun or any other airgun that does not have the more typical hammer hitting a valve type design. But for designs that function by a hammer blow on a valve, regulated or not, I continue to believe shooting to low pressure will not harm the gun. Some people apparently empty their gun of air this way. If your bleed screw doesn't work you could have no choice. 3 of my 5 PCPs are P35s. They do not have a gauge on the regulated chamber. So you cannot know where the regulator is set other than shooting them to the point that velocity falls. That is shooting them under the regulator setting. It does not harm them in any way.

But I don't recommend anybody shooting an airgun below the point where the velocity falls off below what is useful for what you are doing. Doesn't make sense to me. But I don't think it will hurt the gun, it has not hurt mine.

Been emptying guns by shooting the to zero for decades, Sumatras and Sam yang for example do not have a bleed valve so shooting to zero is the vay to go,....my Evanix have a bleed valve but often I've shot the to zero just because

You risk opening a portal to another dimension. Last time it happened we lost most of our dinosaurs. .............................. just kidding.

I've switched to hammerless guns, Huben and LCS. They will shoot below the regulator set pressure with no problem. BUT don't shoot below 100 bar. There isn't enough to keep the proper balance to operate the valve trouble free. It manifests it's displeasure by ceasing to operate. To date bleeding down gun to 0 then refilling it resets the rifle.

I don't know of a rifle that you will harm by shooting it down. That said, there is an awful lot I don't know. As a practical matter, it's moot. Whether regulated or not, at low pressure, it's unregulated, and I see no need to shoot at very low pressure, because the rifle will be out of it's optimum performance range at that point. My advice, learn your rifle's performance range and refill accordingly.