Question on regulated guns as to accuracy diminishing after you are off the reg

Once off the reg your FPS continues to drop from shot to shot, so your pellet energy decreases and you will notice point of impact shifts on target. Some pellets prefer certain velocities for best stability in flight. As the FPS drops, you may also notice not only POI shifts but also accuracy changes. 

Those POI shifts and accuracy changes are more apparent the further the distance to your target. If you’re generally shooting at 50 yards, you’ll notice a change much faster than if you’re shooting at 20 yards. If your range is close, say 20 yards, you could technically shoot down to lower pressures without much perceived change to POI or accuracy. 

Not always an immediate DROP in FPS/POI when you drop off the reg unless the gun is tuned TO the reg pressure. Not unusual to see a jump in FPS/Sound for a few shots when going below reg pressure. If the reg isn't limiting the pressure, it isn't limiting the air volume/flow when the valve is open so it will flow more.... Anyone who 'tunes' a reg along with hammer spring / transfer port, usually balances this. And the first 1-?? shots off the reg may not be noticeable until the tank pressure wont support it anymore.

You don't want to shoot below reg pressure on an FX gun for risk of damaging the valve or something in there.

As far as accuracy, I don't think you'd notice much other than the POI shifting lower. For instance, I can shoot my Streamline 22 on Mid power and the accuracy is still there, the pellet just impacts an inch lower at 25 yds.

I like to tune for a pressure. So when the gun drops off the reg it will get another 10-20 acceptable shots. In my S500 it gives me 10 extra shots off reg that stay inside the regulated numbers then starts to fall off drastically. The FTP 900 I'm shooting and tuned get 2 shots off reg before a very noticeable drop in fps.Both guns are set at 90bar. The S500 has a 231cc tube, the FTP's is under 200cc.

Adding a reg will give you a longer sweet spot. Not a longer shot string. Without tuning adjustments, you will usually get fewer shots per fill. A longer shot string only comes at the expense of power. The lower you set your reg, the higher your regulated shot count will be. Just a couple of basics to consider before addind a reg to an unregulated gun with an efficient valve.

tommy,

Here's a link that explains risk of damage by shooting below reg pressure.

https://www.airgunnation.com/topic/wild-cat-is-behaving/#post-329160

Adding a reg will give you a longer sweet spot. Not a longer shot string. Without tuning adjustments, you will usually get fewer shots per fill. A longer shot string only comes at the expense of power. The lower you set your reg, the higher your regulated shot count will be. Just a couple of basics to consider before addind a reg to an unregulated gun with an efficient valve.

Click to expand...

Only to throw a monkey wrench into your explanation can you explain how my ES dropped and shot count went up, without any adjustment, when I switched from 10.3g pellets to 15.5g slugs? ( I already know why)

Adding a reg will give you a longer sweet spot. Not a longer shot string. Without tuning adjustments, you will usually get fewer shots per fill. A longer shot string only comes at the expense of power. The lower you set your reg, the higher your regulated shot count will be. Just a couple of basics to consider before addind a reg to an unregulated gun with an efficient valve.

Click to expand...

Only to throw a monkey wrench into your explanation can you explain how my ES dropped and shot count went up, without any adjustment, when I switched from 10.3g pellets to 15.5g slugs? ( I already know why)

Click to expand...

I'm sorry but your question is a little cryptic for me to understand. I assume you are referring to a 177, other than that I have no idea what your point is. I never said anything about adding a reg not lowering your ES. If you are telling me that after adding a reg to an unregulated gun and your power hasn't decreased and your shot string has increased, without changing anything else, I'm all ears.

There is no rational reason to go off-reg (except in a shot string, and then for only one shot to determine where that line is). Aside from the fact that you instantly lose power and accuracy, you run the risk of damaging your rifle (not to mention voiding the warranty; and yes, a technician can easily tell). Regulated PCPs are designed to maintain a minimum amount of pressure behind the valve to keep the system stable. DON'T DO IT!

A properly tuned gun should be able to shoot 10-20 bar off the regulator (depending on several variables) andvmaintain the set speed

+1 on what Edgunwest said. If the hammer strike (and/or transfer port restrictor) are not adjusted to the knee, it will either have a velocity rise as pressure falls below the setpoint or it will be wasting air.

Thomas............the best way to describe it is when the pressure in the tank drops below the capacity of the regulator.

This is called falling off the regulator. I have fallen off regulators many times with 0 damage to any gun. It would be unheard of in the industry if a warranty claim were voided because someone fell off the regulator. I have no idea where that load of caca came from. Every time you pick an airgun up you risk damage to that gun. Every time you drive a car is a risk.

However, if you should happen to damage something because you fell off the regulator, it can be fixed pretty easily..........odds are about 1000 to 1 that it will ever happen. But it's possible. Its best not to fall off the reg but sometimes it happens unintentionally. It's not like people are going out shooting airguns and one guy jumps up and states, " Okay everyone,.,,,,,,its time to have the third annual falling off the regulator contest!"

the point when the regulator stops functioning, when its supply input pressure is lower than its the set pressure. It’s inlet valve stays open the way that the piston/needle will lift off the seat and can move freely, many think this is not desirable as when you refill suddenly the needle can land in a different spot (as the pistons are very loose fit in the housing in typical designs so there is always some side play) then the result can be erratic behaviour later... not sure about that, my guns don’t do this...

However when you want best consistency, you need high grade of repeatability also In the way you operate the gun also.

i don’t remember getting many duplicates, repeat FPS reading from an unregulated guns however regulated some can do amazingly well!