FPS question on stock Discovery

FPS question on stock Discovery

Joined: December 14th, 2009, 5:18 pm

April 1st, 2011, 4:14 am #1

I finally got my Chrony set up and checked the vel on my Discovery.
It is bone stock except for a mellon adjuster. My question is, what should I be getting
for top fps with a 2000psi air fill?? With my adjuster 1/4 turn from spring bind,I am getting 650, 630fps.
I would have thought it would be better. Any suggestions??

QB78 Deluxe Rich from Mich tuned
crosman 2400KT custom shop with added Discovery air tube
QB79 Rich from Mich tuned
QB2078 mike melick tuned
.22 and.25cal Marauders
Life member NRA and Texas State Rifle Assoc.
.308 corsair
Crosman 2260
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Joined: November 5th, 2008, 8:23 pm

April 1st, 2011, 1:58 pm #2

I can say that my bone stock .177 disco will push 7.9grain CPHP's across the chrony at an average of 985fps.
And I have a souped up .22 disco that I built myself from parts that is like your, in that the adjuster is running at max turns to get the most fps.
And it will put .22 H&N Barracuda 21.14 grains across the chrony at an average of 860fps.
So I'd say your gun is leaking air at every shot or your chrony is on the fritz.
Thanks
Ray
Last edited by ray1377 on April 1st, 2011, 1:59 pm, edited 1 time in total.
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Joined: May 17th, 2004, 4:36 pm

April 1st, 2011, 11:06 pm #3

I finally got my Chrony set up and checked the vel on my Discovery.
It is bone stock except for a mellon adjuster. My question is, what should I be getting
for top fps with a 2000psi air fill?? With my adjuster 1/4 turn from spring bind,I am getting 650, 630fps.
I would have thought it would be better. Any suggestions??

QB78 Deluxe Rich from Mich tuned
crosman 2400KT custom shop with added Discovery air tube
QB79 Rich from Mich tuned
QB2078 mike melick tuned
.22 and.25cal Marauders
Life member NRA and Texas State Rifle Assoc.
.308 corsair
Crosman 2260
Mine was shooting 825 - 850 fps with 14.3 stock. I have an adjuster I made for it to take it down to 800-ish. I'd say your gun has some issues if you're only in the 6-7 range.

"but I'll be needin' that gun, fer squirrels and such."
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Joined: December 14th, 2009, 5:18 pm

April 2nd, 2011, 2:09 am #4

I finally got my Chrony set up and checked the vel on my Discovery.
It is bone stock except for a mellon adjuster. My question is, what should I be getting
for top fps with a 2000psi air fill?? With my adjuster 1/4 turn from spring bind,I am getting 650, 630fps.
I would have thought it would be better. Any suggestions??

QB78 Deluxe Rich from Mich tuned
crosman 2400KT custom shop with added Discovery air tube
QB79 Rich from Mich tuned
QB2078 mike melick tuned
.22 and.25cal Marauders
Life member NRA and Texas State Rifle Assoc.
.308 corsair
Crosman 2260
Not sure what to check as the Discovery air tube was bought complete from Pacific Pellet and
installed on a 2400KT carbine with a 24 in barrel. It is the stock tube and valve and has a
"can't leak transfer seal. I know the Chrony is good as it is brand new and it shows 935fps on my Corsair and 850fps on my
.25 Maruarder.
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Joined: November 5th, 2008, 8:23 pm

April 2nd, 2011, 4:19 am #5

back off your power adjuster a couple turns and shoot it at 2000psi and see if the fps doesn't go up.
Your hammer may be binding on the inside of the tube and causing it to hit the valve with a weaker amount of pressure???
My .22 disco shoots 14.3 CPHP's at 960 with the adjuster turned in.
If that doesn't work, try the tissue or talcum powder test on your breech seal.
Also, run some orange glow citrus based cleaner down your barrel and give it a good cleaning. It could be gunked up.
Just some things to think about.
Thanks
Ray
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Joined: June 10th, 2009, 7:00 am

April 7th, 2011, 9:23 am #6

Mine was shooting 825 - 850 fps with 14.3 stock. I have an adjuster I made for it to take it down to 800-ish. I'd say your gun has some issues if you're only in the 6-7 range.

"but I'll be needin' that gun, fer squirrels and such."
i added a spacer to the back of my hammer spring (an easy adjustment). my disco shoots an average of 845 w/ the 13.5 grain jsb pellets.
Last edited by ranedouglas on April 7th, 2011, 9:23 am, edited 1 time in total.
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