Crossman E9A inconsistant muzzle energy.

[PESCA]

Wonder if you can help with this one fellas?

My E9A (which as far as I can tell, is remarkably similar to the EB20, though it is actually called 'Crossman Model E9A Series, Cartridge Valve), which has not seen much use, is firing with a very varied muzzle energy.

Mostly sitting just under four, but then doing a few crazies at eight to ten. Is it possible that, as it's not been used for some time (if even used at all), it simply needs running in?

Pellets are .20 Field Target Trophy (15.1 grain?). CO2's are Crossman, installed with a little moly around the nozzle.

Wondering if to, and how to polish the internals. What would I polish? Seems very straight forward to dismantle.

Can anyone tell me the difference (if there is one) between the E9A and the EB20 please? Does this term 'cartridge valve' have any significance?

Cheers.
PESCA

[Firestorm]

My EB22 has "crosman" on the side & E9A series, so I reckon it's the same thing.

Russ

[PESCA]

Thanks for that Firestorm.

So it would appear that this range came under Crossman, Benjamin and Sheridan tradenames?

PESCA

[Korium]

B.S are owned by Crosman IIRC, but I'm not aware what the manufacturing arrangements are.
The EB20 doesn't seem to be about any longer in England, but Brocock might be able to help on repairs if needed?.

Giving the internals a polish won't hurt. 0000 wire-wool and Autosol are what I generally use.

[Firestorm]

The EB20 doesn't seem to be about any longer in England,

my local RFD told me that it's no longer being made by Crosman.

Russ

[PESCA]

Thanks lads.

Korium, when you say 'polish the internals', what parts do I polish please?

I'm now on with another problem, as the CO2 capsules aren't being pierced properly, and all of the gas is then discharging Can't get the front cap any tighter though.

PESCA

[Korium]

Korium, when you say 'polish the internals', what parts do I polish please?

I usually do every moving part, particularly one's with a large amount of surface to surface friction.

[lightning22]

I'd be surprised if a CO2 pistol was running that hot on a standard length barrel.

What kind of Chrono are you using? Anything that could be affected by the muzzle blast of the CO2?

In terms of what to polish, the hammer and the cylinder within which it runs is a good place to start, use dry lube or no lube at all. Wet lubes and grease will cause inconsistency.

Rich

[Firestorm]

Thanks lads.

Korium, when you say 'polish the internals', what parts do I polish please?

I'm now on with another problem, as the CO2 capsules aren't being pierced properly, and all of the gas is then discharging Can't get the front cap any tighter though.

PESCA

this more than likely has something to do with the inconsistency. Probably a seal issue.
The EB pistols do run very near to the 6ft lb limit, butstill can't see how yours would jump up that high, def check your chrono.

Russ

[PESCA]

Thanks for that chaps.

Used the little CB chrony on the end of the barrel for this one. Also have a Chrony Alpha, so do you think that I should try that instead? Never really gave much thought to muzzle blast. Is that just particular to CO2 then?

Any ideas why the cylinders might not be punctured correctly? Could it be faulty cylinders? I really can't tighten the end cap up any more.

Sorry for the twenty questions, but never had any dealings with either CO2 or pistols.

PESCA

[lightning22]

I'd definitely try a chrono that is 12" or so away from the muzzle. The short barrel of a CO2 pistol tends to limit the power as the pellet exits before the CO2 has finished converting from liquid to gas, hence the fire extinguisher effect.

If you are having problems with piercing it might be worth trying a different make of cylinder, Crosman is a good bet.

Rich

[PESCA]

Thanks for that lightning22. I'll try using my Chrony Alpha.

The cylinders I'm trying are in fact Crossman. I do have some new Crossman ones coming this week so I'll try them before making any adjustments. Tried four in a row, all with the same result.

Cheers.
PESCA