20 fpe qb-78?

Right now i just got my 22 al conversion done on my AR. And as it sits with the bolt probe mod and drilling out the transfer port its making about 15.1 fpe with superdomes (725 fps) and crow mags(615fps). It also has a full power valve, etc. from Mike M.
Is there anyhting left to do to raise the power up even higher? Maybe bulk fill it??    Id even be happy with 18 fpe...


Any help would be appreciated, thanks!!


Jason

[DanoInTx]

Bulk fill, chop the piercing pin off the valve, maybe get you a few more FPS.......add a regulated remote HPA tank at about 1100 psi and you could do some damage:)

[JMG]

So are ya saying that the setup in Co2 form as it is right now Dan can not be modified any further to get him a little more outta the gun? Hmm I am also kind of curious about tube extender's... be nice to be able to up the shot count some without going to mounting an actual paintball tank on there. I may be wrong... but just doin a little simple math I am thinking that an increase of tube length by 3" could prolly net ya 15 more shots?

John

[ribbonstone]

Are pretty much workingat the top end of what CO2 can do...it gets more and more wasteful of gas the higher you go.

BAsically, as we can't increase pressure, we have to incrrease the amount of gas in order to make the pressure last longer...but once most of the increase is being squired out into the atmosphere, the vel. gains get less and less.


But if you were to fit a .25cal barrel to what you already have, would be a little slower, but would proably be at or past 18foot pounds.
(using the OTHER way to get gas drive energy...rather than squirting out a longer blast, squirt out a WIDER one).

[DanoInTx]

I honestly have no idea about how many extra shots that will give you.  I think the bulking and the simple removal of the powerlet from right outside the valve inlet will give you a very few extra FPS...so yes, the bulking may help a bit, subract the piercing pin and flow is even smoother....but CO2 is only going to be at 850PSI +/- at 70 something degrees.  You need either volume or pressure, the first part will help get the volume faster, the HPA will give you a tad more pressure.  Don't bother bulking the tube for HPA though, I think you will be disappointed.

[DanoInTx]

ribbonstone - 6/19/2007  9:16 PM

Are pretty much workingat the top end of what CO2 can do...it gets more and more wasteful of gas the higher you go.

BAsically, as we can't increase pressure, we have to incrrease the amount of gas in order to make the pressure last longer...but once most of the increase is being squired out into the atmosphere, the vel. gains get less and less.


But if you were to fit a .25cal barrel to what you already have, would be a little slower, but would proably be at or past 18foot pounds.
(using the OTHER way to get gas drive energy...rather than squirting out a longer blast, squirt out a WIDER one).

I couldn't of, and didn't say it any better.  Pretty much just squirting CO2 and making more noise!

[ribbonstone]

Dano hit the nail on the head...bulking does gain a little vel., but that's through better gas flow/more gas flow than any increase in pressure.
(although, that piercing pin also actas as a valve limiter...valve can't open any farther than the pirecing pin will let it, and with a co2 cartrige jammed up against it, it takes several shots to beat a full-size hole into that cartridge's seal).

Once you HPA it, then it's not limited to the constant co2 pressure...there is a limit to what the tube, 0-rings, valve body will take without failing, but most HPA folks are running at something in the uppper pressure limits of CO2 (lets say C02 at 92degrees..somthing close to 1100psi).  

So..if running at the same pressure (HPA at 1100psi or co2 at 92degrees), why does HPA shoot faster?

Air is lighter than co2...in molecular terms, air is made of smaller molecules (on average) than CO2... more of it moves through a open/shut valve...more power at the same upper limits of pressure.  taken to extreams, some PCP shooters ahve tried Helium (even smaller molecules...more flow..higher speeds).

Down side to HPA is that you get WAY -WAY fewer shots per fill and need a good way to generate that kind of pressure.   IF you go to the expense of generating that kind of pressure, may as well generate full PCP presure and use a true PCP rifle

[IJL]

If you go for a full PCP conversion then 35+ fpe is easily done in .22.
And as another contributor has said, the wider the pellet the more energy you can get into it.

Ian

Would going to bulk fill and an extended tube possably gie about 50 more fps? i know thats alot but htat should bring it up about a pound and a half of energy. And I think my math was wrong... heh 14.5 grains @ 725 fps is like 16.9 fpe


Incase anyone is wondering why I care and why im wanting to do this. Well I like to tinker alot with the guns and try different things. I also wanted a cfx .22 really bad. Well money fell short and I got a .22 for the AR. And so far im at about the same power level as the cfx. Im pretty happy about that concidering I save almost $200 by not buying a new gun, and no recoil really rocks!

[ribbonstone]

Extended tube shouldn't make any real difference to velocity...just give you more shots before refilling.

Bulk filling lets you remove the piercing stem (and reshape the inlet of the valve if you desire) which does improve flow, and that can earn a bit of additional speed.  Maybe not the 50fps you're looking for as you've already tuned it up a good deal to get to where you are now.