disco factory parts for power

[lorraine]

Can a 22cal stock disco be made to shoot @ 45fpe using only oem parts from crosman?

[Motorhead]

Can a 22cal stock disco be made to shoot @ 45fpe using only oem parts from crosman?

On 2K fill pressure ... IMO Not very easily

[rsterne]

Nope, not using a stock unmodded valve, stock hammer spring with no RVA or shimming, stock transfer port and barrel etc.... In fact, you would be lucky to get to 30 FPE....

With enough machining, and STARTING with Crosman parts, it's possible to hit 50 FPE at 2000 psi with a 32 gr. pellet.... but you might need a stiffer hammer spring, although the new Disco spring might just do it....

Bob

[Monkeydad1969]

Nope, not using a stock unmodded valve, stock hammer spring with no RVA or shimming, stock transfer port and barrel etc.... In fact, you would be lucky to get to 30 FPE....

With enough machining, and STARTING with Crosman parts, it's possible to hit 50 FPE at 2000 psi with a 32 gr. pellet.... but you might need a stiffer hammer spring, although the new Disco spring might just do it....

Bob

X2

[Norm_m]

OK my Disco bottle gun is coming along very well, just waiting for some bottle bands!
Did a little testing yesterday and got the following 2 strings:
String 1 - 2000 PSI fill, 1000 PSI end, low fps 814.21, high fps 967.16, average fps 910.66, es 152.95, sd 41.53 and fpe 27.00 for 35 shots. This was accomplished with a modified valve, factory hammer, factory spring and factory TP & barrel port using 14.66 gr pellets

String 2 - 3000 PSI fill, 1900 PSI end, low fps 969.79, high fps1032.14, average fps 1002.27 fps, es 62.35, sd 13.24 and fpe 32.71 for 59 shots. This was accomplished with a modified valve, factory hammer, factory spring, factory TP & barrel port and a RVA set at 1/2 turn CCW from coil bind using 14.66 gr pellets

I hope to test this with some heavy pellets on 5/16 or 5/17

Norm

[rsterne]

String 1 - I assume this is with the new, stronger Disco hammer spring?.... and I'm guessing that the velocity started at 967 and dropped from there.... I'm also guessing that if you stopped when the velocity had dropped 4% (ie to 928 fps) you would have stopped at about 1700 psi or so?....

String 2 - no idea what the curve looked like, it would be much more informative if you reported the velocity at the beginning (3000 psi), pressure at the peak velocity, and velocity at the end (1900 psi).... That would give some idea of what the usable pressure range is to keep the shots within a 4% ES.... A greater ES than that is really only usable at close range....

Bob

[Norm_m]

Yes it was the NEW factory spring

All the strings are just to get a base line for what is to come.

String 1 & 2 used H&N FTT 14.66 gr pellets

3rd string used H&N Barracuda 21.14 gr pellets

4th string used JSB Jumbo  Monster 25.39 gr pellets

String 1- 2000 PSI fill, 1000 PSI end, low fps 814.21, high fps 967.16, average fps 910.66, es 152.95, sd 41.53 and fpe 27.00 for 35 shots. This was accomplished with a modified valve, factory hammer, factory spring and factory TP & barrel port using 14.66 gr pellets. 1st shot was 963.92 and the next 9 stayed in the low to mid 900s, the 4% would have been on the 20 shot but I was not watching the pressure for each shot

String 2 - 3000 PSI fill, 1900 PSI end, low fps 969.79, high fps1032.14, average fps 1002.27 fps, es 62.35, sd 13.24 and fpe 32.71 for 59 shots. This was accomplished with a modified valve, factory hammer, factory spring, factory TP & barrel port and a RVA set at 1/2 turn CCW from coil bind using 14.66 gr pellets

String 3 - 3000 PSI fill, 1500 PSI end, low fps 822.85, high fps 903.49, average fps 869.73, es 80.64, sd 20.09 and fpe 35.52 for 76 shots. This was accomplished with a modified valve, factory hammer, factory spring and factory TP & barrel port.

String 4 - 3000 PSI fill, 1500 PSI end, low fps 745.15, high fps 827.18, average fps 794.76, es 82.03, sd 21.48 and fpe 35.62 for 80 shots. This was accomplished with a modified valve, factory hammer, factory spring and factory TP & barrel port.

Now that I have the 4 strings above I will increase the TP & Barrel ports to .160 and see what the strings using the heavy pellets will look like. Seeing this is where the Bottle Disco is heading I will record the pressure more closely.

I'm hoping to be in the mid 40 FPE with a minimum of 20 shots!

We'll see
Norm

[rsterne]

I assume that the tank you have is a 13CI tank (215 cc).... That being the case, your shot count should match an MRod at the same power levels.... In fact, I guess you should get more shots because you have part (or all) of a Disco tube in addition to the tank.... My 2260 HPA uses a 13CI tank regulated to 1600 psi, and gets 40 shots at 37 FPE with 18 gr. JSBs.... from 3000 psi down to 1500.... The tank feeds a 2260 tube, which is 65 cc....

Bob