PCP pistol

[clip]

I'm having a difficult time wrapping my mind around what size scuba tanks will and won't fill a PCP airgun. Does anyone know if a PCP Marauder pistol's reservoir is the same as a Marauder rifle? They're both listed as a 3000 fill but is it the same measurement? All I have is an 80cf scuba tank that I can't use for anything other than a 2000 fill Discovery. I'd like a PCP pistol but I don't want to buy another tank.
 Guess my question should be: Is a 3000 fill pistol and a 3000 fill rifle measured the same way?
 Thanks..
  Larry

[Nomadic Pirate]

3000 psi is 3000 psi no matter what the size of the air chamber is.


and no the pistol and rifle have different reservoirs

[rsterne]

The reservoir on a PRod is only about 1/3 the volume of that on an MRod.... about 65 cc compared to 215 cc.... They can both be filled to a maximum of 3000 psi.... so you can't fill them completely from a 3000 psi SCUBA tank.... However, both can be tuned to work fine at a lower fill pressure such as 2600 psi and then you can get many fills.... There is a fill calculator link on the top of the Library page....

Bob

[cactusrat]

Volume is what makes the difference.

Lets look at it the way.

How many cups of water can you pour out of a quart pitcher? Now, how many cups can pour out of a gallon pitcher?

The pressure is the same in both cases, lets say at sea level.

With a smaller tank you will get less fills than a larger tank, if the starting pressure is the same. The smaller tank will run out of air first (no air, no pressure). On the larger tank each fill of the gun uses less of the total volume of air in the tank, giving you more fills.


Edited: Bob and Manny beat my reply. Hope all this give you a clear picture.

[Ribbonstone]

The .177 and 22 MRods generally come set working thier best at about 2700-2600psi (not sure about the .25 version). The PRod about 2600-2500psi.  With the factory adjustments, could certainly set them to work well at those pressures or less.

Can certainly fill them with a 3000psi tank.
use this calculator:
http://www.airgunsofarizona.com/Tanks/FillCalc.html

If you set the gun to run well at 2600psi and refill at 1600psi, your 80cf tank could:

Fill a 220cc air tube (like the MRod)  20 times
Fill a 66cc air tube (like the PRod) 67 times

[clip]

Volume is what makes the difference.

Lets look at it the way.

How many cups of water can you pour out of a quart pitcher? Now, how many cups can pour out of a gallon pitcher?

The pressure is the same in both cases, lets say at sea level.

With a smaller tank you will get less fills than a larger tank, if the starting pressure is the same. The smaller tank will run out of air first (no air, no pressure). On the larger tank each fill of the gun uses less of the total volume of air in the tank, giving you more fills.


Edited: Bob and Manny beat my reply. Hope all this give you a clear picture.

Cactus...That makes sense when it's explained that way, Thanks.

The reservoir on a PRod is only about 1/3 the volume of that on an MRod.... about 65 cc compared to 215 cc.... They can both be filled to a maximum of 3000 psi.... so you can't fill them completely from a 3000 psi SCUBA tank.... However, both can be tuned to work fine at a lower fill pressure such as 2600 psi and then you can get many fills.... There is a fill calculator link on the top of the Library page....

Bob

 Thanks Bob..All I would need to do is find someone who knows how to detune one.

.[quote
 

author=Nomadic Pirate link=topic=19007.msg165946#msg165946 date=1317518826]
3000 psi is 3000 psi no matter what the size of the air chamber is.


and no the pistol and rifle have different reservoirs
[/quote]

Thanks, Nomad..I kinda figured the reservoirs were different but I wasn't sure what the differences were.
  
Thanks guys, for putting up with my elementary..( read "dumb" ).. questions. Springers and gas rams I can figure out...it's the PCP filling pressures that are fooling me.

[clip]

The .177 and 22 MRods generally come set working thier best at about 2700-2600psi (not sure about the .25 version). The PRod about 2600-2500psi.  With the factory adjustments, could certainly set them to work well at those pressures or less.

Can certainly fill them with a 3000psi tank.
use this calculator:
http://www.airgunsofarizona.com/Tanks/FillCalc.html

If you set the gun to run well at 2600psi and refill at 1600psi, your 80cf tank could:

Fill a 220cc air tube (like the MRod)  20 times
Fill a 66cc air tube (like the PRod) 67 times

  Thanks for the link, Ribbon...I'll check it out.

[rsterne]

All I would need to do is find someone who knows how to detune one.

or leave the factory tune alone and just shoot it.... They come factory set for about 2600 psi....

Bob

[clip]

All I would need to do is find someone who knows how to detune one.

or leave the factory tune alone and just shoot it.... They come factory set for about 2600 psi....

Bob

 I wasn't aware that they were factory set for that pressure. It puts a whole new outlook for the PRod in my future.
 Thanks, Bob

     Larry

[Ribbonstone]

You never get the max. fills.  The air between the tank valve and the gun's intake gets vented off when you disconnect...but you get most of the full fills.

Doesn't count the "almost full" fills...like getting 2550 or 2500 instead of 2600...so you can stretch out that 80cf tank a bit longer if getting it refilling is a PIA.

MRods usually come set for about 2700-2600 also.

But tuning them is pretty simple. The factory suppled 3 adjustments on the MRod and 2 on the PRod. A chronograph and the wiliness to experiment can set it the sweet spot pressure where ever you'd care for it.