FD XS60C PCP Rifle

[dcmeyer]

I've been talking with Mike at Flying Dragon about some tuning and parts for a break barrel I have and I was looking over his website. This rifle, XS60C PCP, entry level PCP converted from CO2 can get 15 shots in .22 with a 1500 psi fill, is that right? What am I missing.

http://flyingdragonairrifles.org/index.php?route=product/category&path=63_65

I just bought a new rifle and I'm not really shopping but everyone talks highly of Mike but the products seem to good to be true, for the price, how good can they be.

[avator]

Buy from Mike with confidence. You won't go wrong.

[Bentong]

I get 20 useable shots, using CPHP 14.3 @ 19fpe. Mine is a gen2 version with safety on the trigger guard. Pleasure to shot and easy to pump back to 1500.

[Ribbonstone]

Count in another (.22) still being used (Gen. 1) with no complaints.

[Hoosier Daddy]

While not the PCP conversion, I have a XS60-C from Mike and it is easily one of my favorite airguns. so light and shaped just right.
 I bought one of his "bulk fill" adapters and teather it to a bottle with HPA regged down to 900 psi CO2 pressures. At the end of the day I will close the valve and shoot it down to disconnect the whip and get about 5-6 more shot to empty... so it is quite evident to see how he could get that kind of shot count out of 1500 psi in the tube.

[nervoustrigger]

Like Ribbonstone, I enjoy my .22 cal Gen 1.  A lightweight, accurate rifle for hitting the woods in pursuit of gray squirrels.  Have also used it to deal with some pesky raccoons that were emptying my feeder at night.
https://www.gatewaytoairguns.org/GTA/index.php?topic=135634

[avator]

I too have one of the 3 original Gen1 Fd-PCP guns I got from Mike. I have a .177 and a .22 barrel and bolt for it. Still runs like the day I got it. Added the BStaley buffer and it runs a Stalwart massaged trigger group. It still holds air forever.

[dcmeyer]

Wow, those are some convincing testimonials. I do get a good feeling talking with him that he really is a stand up guy. I guess what I'm confused by is that's a pretty low pressure to start at, around 100 bar. Seems most PCP's start dropping velocity by that point so I don't understand how you get that many shots at 800fps starting there. And yeah, that would be easy to pump back up!

I've only had my first PCP a couple of weeks and my chono is coming this week so I'm really new to all this. Who would have known after shooting all my life that air rifles would teach me so much about the science of it. Those "dang" powderburners have spoiled me!

[avator]

It's because these guns were meant for C02 pressures and not HPA. The valves are set up to be more conservative.

[dcmeyer]

It's because these guns were meant for C02 pressures and not HPA. The valves are set up to be more conservative.

Forgive my ignorance but if that is possible why are modern PCP's such air hogs by comparison.

[avator]

Because they are designed for HPA exclusively. A typical C02 is run  at 1900 psi? And that's only after the C02 turns from liquid to gas. HPA is a stored pressure in the air tube. Someone correct me if I'm wrong.

[Ribbonstone]

Just to mention...as far as the stress to the rifle is concerned...pressure is pressure.  Doesn't matter a bit if it is Aardvark farts, co2, air, or Helium, pressure is a measure of the force applied to the container (and any valve attached to the container).

Co2 can easily top 1500psi in warm weather,so the stress on the mechanics is really no different than August shooting co2 out in the heat or 1500psi  PCP air shooting.


One gas is fater than the other at the same pressure...SAME PRESSURE...but becasue the "thinner"gas flows more freely/expands faster (can call it molecular weight/molar value.or whatever...the thin stuff (at the same pressure) shoots faster).

[Hoosier Daddy]

Because they are designed for HPA exclusively. A typical C02 is run at 1900 psi? And that's only after the C02 turns from liquid to gas. HPA is a stored pressure in the air tube. Someone correct me if I'm wrong.

I think you got a 1 in there that doesn't belong.
Depending on the ambient temp of course, CO2 is usually 850 to 950, maybe 1000 psi on a regular "optimum" summers day. Below 65 degrees it gets unusable because it falls below the PSI needed to work.

[Ribbonstone]

While it might only be 90F outside, if the rifle isn't in the shade, it can easily get up to 110F.

Considering the fill to be full (which in the following chart does include the "air space" rahter than turley full of liquid co2) can see somthing close to 1800psi...although usually a paintball tank will pop it's burst disk by then.

So, yep...in normal summer use, maybe 1000-1100psi...but past that point, UNLIKE air, it kind of goes "nuts".

 
http://www.spudfiles.com/spud_wiki/images/8/8d/Co2_pressure_vs_fill_phases.jpg

[dcmeyer]

I guess my question was misunderstood.

I was wondering how they are getting that much velocity at such low pressures.

Again, I am uneducated on the subject but all the data I've been looking at suggests velocities in shot strings in a typical PCP rifle start to fall off to the mid 700's at 100 bar or even higher on a .22 or .25 and that's where the starting pressure is in this rifle is. So how does it sustain a average velocity of 800fps over 15 shots when by half hay through the string pressure has to be much lower that the 1500 psi it started at, well below 100 bar. If that efficiency was possible on a standard PCP, why wouldn't they be valved that way. Why are PCP's running at 200 bar if they don't need to. I can understand valving being different to accommodate CO2 but were talking about compressed air, not CO2 and the energy required doesn't change.

Not trying to be a pain but I guess the light is just not coming on for me.   

[Bentong]

I had to detune mine and I have to clip 2 coils of the hammer spring and back out the power adjuster all the way back but that started  with 612 fps with 14.3 CPHP. Had to tweak the adjuster until I started with 782 fps then after 10 shots I peaked at 942fps then down to 788 at the 20th shot..end pressure somewhere between 850-800 psi using the pump gage. I still need to tweak it and get rid of the mid 9's...might have to close 2 of the 3 ports in the barrel. Gen1 barrel only got 1 port. Can't complain with the FD PCP I got for I only paid $85 used for it. My Benjamin Maximus holds 2000 psi and gets 40 usable shots starting at 765 fps with 14.3 CPHP tops at 813 fps then 762 fps at 40th shot. It's got bigger tube and the 500psi difference doubled the shot count. Maximus is detuned and power adjuster installed.

[Ribbonstone]

JUst my thoughts on it.

We hardely ever play at the low end of pressure with non regulated PCP's.....but do with regulated PCP's. And just like them, it's a matter of getting the balace right.
Balance would be between the force opening the valve (striker hit to stem) and the force closing the valve (air pressure). 

Non-regulated rifles can do a pretty good job of keeping in balance over a very short pressure range.

Bob (rstern) has done very good work figuring out the best balance of air use to power with regulated rifles. It's not intuitive and the regulator kind of covers up the evidence with each cycle, so but if you dig up the posts (with a search) can see the same idea of "balance" at lower (regulated output) pressure.

Ignoring all the follow up shots and just looking at  an individual shot, in one case (regulated) we have a small volume (plentium size) of (just picking a number) 1200 psi air.  On the other (FDPCP) have a large volume of 1200psi air (the whole tube).

Here I have to give the FDPCP some bonus points for a pretty clean flowing air passage from valve to barrel....clutter that up with narrow spots/hard right angles, and it's not so easy.)
So during the actual shot, the regulated rifle taps off from a small volume of 1200psi air...small enough that it seriously drops in pressure during the shot, so not a full plentium volume of 1200PSI during the shot.  Regulator kicks in and refills the plentium, but not in time to help with the shot.

In the non-regulated rifle, there is also a slight pressure drop, but such a large volume that the drop is a small amount, so the push supplied is closer to all 1200psi.

SO...it's a lot like getting a regulated PCP running well with a 1200 psi regulator setting.  Whatever power you can make with one 1200psi system, can make with the other....just for not nearly as many shots.


ASIDES:

Long long ago, were airguns (like the 1700's) that actually could get a reasonable number of effective shots from what today would be a really low fill pressure.  They used a whole lot of air per shot, but it was delivered effectivly (in balance).

NOt so long ago (1970's), but well before a serious internet...some folks tried compressed air in bulk fill CO2 rifles. Not easy to find mention of those experiments, but they seem to have been realitvily unbalanced systems, geared more to one or two powerful shots rather than what we'd think of as a shot string (but they COULD have been, it just didn't suit the use they were putting them to).

Did read of Davis Schwienger (and I likely misspelled that)  hunting with a Farco 28ga. co2 shotgun (as a smooth bore with a lead ball), using a 1200psi air fill rather than the co2 it was designed for.  Tremendusly l long barrels/gas tubes on those old guns.

Anyway...as always seems to happen...other folks took it to higher and higer pressure.  Evidently one of them had a major "whoops"  and either lost a hand or at least part or one.

BUT...it did kind of catch the attention of airgunners, and eventatully factory made/safe PCP's started being made...which pretty much is the zig-zag trail to today.

The FDPCP is kind of de-evolution.  It's safe with a 1500psi fill....and although folks get away with more, I'd rather not risk waving "by by"with one eye or 1/2 a hand.

[moorepower]

I guess my question was misunderstood.

I was wondering how they are getting that much velocity at such low pressures.

Again, I am uneducated on the subject but all the data I've been looking at suggests velocities in shot strings in a typical PCP rifle start to fall off to the mid 700's at 100 bar or even higher on a .22 or .25 and that's where the starting pressure is in this rifle is. So how does it sustain a average velocity of 800fps over 15 shots when by half hay through the string pressure has to be much lower that the 1500 psi it started at, well below 100 bar. If that efficiency was possible on a standard PCP, why wouldn't they be valved that way. Why are PCP's running at 200 bar if they don't need to. I can understand valving being different to accommodate CO2 but were talking about compressed air, not CO2 and the energy required doesn't change.


It's valve is designed for CO2 which is a denser gas than air, so its porting/ air passages are larger. This is why when you put in a thinner gas,"air" it has a higher velocity. Running at lower is not efficient in air usage, but it does produce more velocity. I bought a .177 and a .22 when they were the ticket for the $100 PCP. They are both quite accurate for a $100 PCP, but knowing what I know today, I would pick up a Maximus on sale. At the time I did not even know what a "Disco" was, because I never even considered them to be much more than a BB gun. Crosman and the aftermarket have tons of replacement and performance parts and if you so desire you can still tune to a 1500 psi fill with a lighter hammer spring and or power adjuster or enjoy the 2000 psi fill for more shots. Their are many choices for inexpensive PCP's that were not available when I bought them.
Not trying to be a pain but I guess the light is just not coming on for me.