Topping off question from a newbie...

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MikeyPewPants

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May 6, 2022
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Michigan, United States
So I'm completely new to PCP airguns... I never really paid airguns all that much attention in general, actually. Recently I was looking up a CO2 gun and it resulted in me falling down a rabbit hole resulting in my new obsession with PCP airguns.



I'm still researching and learning about this stuff before I make the jump and get my first one, and there's an answer to a question I can't seem to find through searching, so I thought I'd just join a forum and ask.



I'm looking at an FX Wildcat Mk. 3 - BT compact. I'm trying to get an idea of how many top off fills I could get from different sized tanks, but I can't find an answer to at what point you would top off. I've seen some stuff that stated you would top off at 2,000 psi but those guns were all 3,000 psi. I wasn't sure if 2,000 psi was a universal point for topping off or if it changes with different pressures/capacities etc.



So are there some guidelines for when you would top these guns off?



Thanks.
 
When you get a new pcp gun, what you need to do is buy a chronograph also, fill it to its stated top pressure, and just shoot it over the crony, and record the numbers. you will see what is called a shot curve, (when the numbers are plotted on a graph, which is easy to do. I believe there are apps for this purpose.) the velocities will begin to drop off at some point which you will stop and need to re-fill. You will need to keep an eye on what your fill pressures are during this time also. Once you do this a few times, you will have a good idea where within the shot curve the tightest numbers fall, and between what fill pressures. Eventually you will find that you will get the tightest group of numbers (and best accuracy between a certain spread of pressures. This operation needs to be repeated with each type of pellet or slug you try.

Now this is a very simple explanation of how to find out the answer to your question, as all guns are different slightly, and with each individual type of ammo used. Since you are looking at an FX, that is likely regulated, there won't be as much of a shot curve so to speak. the string will be more strait and will then fall off quickly at some point. It will likely be at the point the tank reaches the same pressure that the regulator is set at, that the velocities will begin to fall off. So if the regulator is set at 140 Bar, and the tank pressure is filled to 300 bar, around 140 bar will be the point you would need to re-fill. it depends on the numbers though. hope this helps, and if you already knew most of this, my apologies. I wasn't sure how new you are to this stuff.

Thanks,

V
 
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When you get a new pcp gun, what you need to do is buy a chronograph also, fill it to its stated top pressure, and just shoot it over the crony, and record the numbers. you will see what is called a shot curve, (when the numbers are plotted on a graph, which is easy to do. I believe there are apps for this purpose.) the velocities will begin to drop off at some point which you will stop and need to re-fill. You will need to keep an eye on what your fill pressures are during this time also. Once you do this a few times, you will have a good idea where within the shot curve the tightest numbers fall, and between what fill pressures. Eventually you will find that you will get the tightest group of numbers (and best accuracy between a certain spread of pressures. This operation needs to be repeated with each type of pellet or slug you try.

Now this is a very simple explanation of how to find out the answer to your question, as all guns are different slightly, and with each individual type of ammo used. Since you are looking at an FX, that is likely regulated, there won't be as much of a shot curve so to speak. the string will be more strait and will then fall off quickly at some point. It will likely be at the point the tank reaches the same pressure that the regulator is set at, that the velocities will begin to fall off. So if the regulator is set at 140 Bar, and the tank pressure is filled to 300 bar, around 140 bar will be the point you would need to re-fill. it depends on the numbers though. hope this helps, and if you already knew most of this, my apologies. I wasn't sure how new you are to this stuff.

Thanks,

V
Click to expand...

Okay, that makes sense. So, basically, I need to just jump in and start figuring these things out based on how I'm using it.

Thank you.
 
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Greatgrips23's explanation is good for an unregulated gun but the Wildcat is regulated. With a regulated gun you fill it up after the tank pressure gets down to the regulator pressure. If you have a gauge for both you just look. One of mine does not have a gauge on the regulated chamber so I just had to watch the velocity as the tank pressure came down to get a good idea where the regulator is set. You see the velocity go down when the tank pressure goes below the regulator pressure.
 
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You can notice when your gun needs to be refilled your pellet will move a lot after a while you get used to what pressure you have to refill my daystate revere i can shoot 3 mags after that the POI will change so i refill more often but its more accurate my dream tac with 480cc bottle i get over 100 pellets and i fill it but it could go further 
 
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You can notice when your gun needs to be refilled your pellet will move a lot after a while you get used to what pressure you have to refill my daystate revere i can shoot 3 mags after that the POI will change so i refill more often but its more accurate my dream tac with 480cc bottle i get over 100 pellets and i fill it but it could go further
Click to expand...

Yeah, I mean even with how new I am to this, it seems obvious after hearing it that you would have to fill it when the regulator and supply pressure meet.



You can notice when your gun needs to be refilled your pellet will move a lot after a while you get used to what pressure you have to refill my daystate revere i can shoot 3 mags after that the POI will change so i refill more often but its more accurate my dream tac with 480cc bottle i get over 100 pellets and i fill it but it could go further
Click to expand...

I was asking more for an idea of what I should buy with the gun. I'm going to buy a tank with it for refills, so I wanted to have an idea of how long the tank would last between having to have that tank filled by someone so I can get an idea of how valuable having a compressor would be.



But I should probably stop overthinking and just get a feel for all of this by using it like you said.
 
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Mikey -

There IS no hard, pat answer ! The answer depends on a few...things -

1.) The "actual" pressure in the guns air cylinder ("bar" pressure gauges are NOT very accurate) when you decide to...top it off.

2.) The "actual" pressure that you "end up", actually putting into the guns air cylinder ("bar" pressure gauges are NOT very accurate).

3.) The "actual" pressure that's in your supply cylinder. As the supply air pressure drops, the "available" pressure will be lower than with a "full" supply cylinder, and thus not be able to "fully"...top off, your guns cylinder "completely".

And one note - ALWAYS...fill your new gun "slowly" to help keep moisture to a minimum. In other words, do not let the guns air cylinder get warm.

Mike
 
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Greatgrips23's explanation is good for an unregulated gun but the Wildcat is regulated. With a regulated gun you fill it up after the tank pressure gets down to the regulator pressure. If you have a gauge for both you just look. One of mine does not have a gauge on the regulated chamber so I just had to watch the velocity as the tank pressure came down to get a good idea where the regulator is set. You see the velocity go down when the tank pressure goes below the regulator pressure.
Click to expand...

Great grip explained the whole regulated gun procedure on his bottom paragraph 
 
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if you plan on shooting a lot and mostly near home i’d suggest you spend the extra for a compressor and forget the tank as in the long run it will be cheaper
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I'm definitely going to need a tank one way or another. I plan on shooting at my lake property. That was part of why I was trying to figure out how many fills I would get out of one. So Id already have the tank and figured, if it lasted long enough, it wouldn't be that much of an issue to get it filled now and then and I wouldn't have to worry about a compressor.


I guess I won't know if the compressor will be worth it until I see how much I end up shooting it and how far a tank will get me. I could only need a tank refill every couple/few weeks... or every couple/few days.



Although, in reality, I know I'll probably just end up getting a compressor no matter what. I'm lying to myself pretending like I'm going to be frugal about any of this.
 
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Disregarding shots per fill, this webpage can give you fills per tank.

https://www.airgunsofarizona.com/Tanks/FillCalc.html

Example with my Dreamline with a 300cc bottle:

Capture5.1651898454.PNG


In reality I use a compressor, but the airgun numbers are real.
 
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I'm definitely getting a larger tank. I was looking at the Great White but ended up leaning towards getting the 98/cf AirMarksman tank at Utah Airguns because they carry everything I was going to buy, so I thought I'd just get everything from them all at once.



I do like that the Great White is made in America though. Do you happen to know where the AirMarksman tanks are made? I saw some stuff suggesting they are imported, but I don't remember seeing anything definitive on that. All else being equal, I'd probably want to go with the American made product.
 
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