TargetTalk

I hope you do not get upset by my asking the coaches but I would like to know from experience what is considered a very good string for the challenger CH2009 with 7.33 grain pellets. JSB 7.33 and AA Falcon 7.33 seem to shoot the best at 10 MM for me. Would like to know the best string so I can adjust to it. This is what I am getting now:
Total 70
Start psi 2000
End psi 1400
Dif 600
High 557.6
Low 526.2
Average 546.2
3%drop 18.0
% of drop 12.30%
Hi-Lo 73.8
FPE-A 4.86
FPE-H 5.86
FPE-L 4.51
ST-Dev 7.4
Pressure Drop CI 542.9
FPE/CI 70.000
PSI-shot 8.57

As I said, 7.4 St.Dev is actually pretty good for the challenger. It's a unregulated PCP with a lower fill pressure AND lower volume than say a FWB tank. You can adjust hammer stroke length and hammer spring pressure, look in the manual. Maybe you could get it down to 5 fps St.Dev if you really tinker with it, but for a sporter air rifle it's really not worth it, unless you are trying to shoot it in the precision class. (In that case, watch for the twisting butt plate!)

I will NOT go into details about it, but you can regulate the Crosman Challenger. It is NOT LEGAL in SPORTER class competition however.

I guess I don't understand your question. Are you asking if your pressure limits versus your muzzle velocity is acceptable?
Are you asking if your accuracy is ok FOR A CHALLENGER?

metalsmith wrote:I guess I don't understand your question. Are you asking if your pressure limits versus your muzzle velocity is acceptable?
Are you asking if your accuracy is ok FOR A CHALLENGER?

I am wondering what I should be looking for in a shot string. I have heard that I should look for at least a string of 70 and what is the best FPS that string should consist of. Or should I be looking at a longer string and pick out of the middle? Would like to get into 10M target shooting.

The ideal string is......consistent. Doesn't matter if your shooting 400 or 599 (600 is the limit) because although the length of time the pellet is in the barrel increases with slower velocity, it's so little with decent follow through it shouldn't matter. I backed the power adjuster out on my mechanically stock challenger, shoots much shower than set from the factory; I get around 120 good shots from it before it starts dropping off. After that it's a click up every two shots....

Your string looks real good, keep in mind as your gun wears in it will get even better. The bolt will also get smoother.

PM sent about a regulator, (He does not plan to use it for Sporter class competition)

Andre wrote:The ideal string is......consistent. Doesn't matter if your shooting 400 or 599 (600 is the limit) because although the length of time the pellet is in the barrel increases with slower velocity, it's so little with decent follow through it shouldn't matter. I backed the power adjuster out on my mechanically stock challenger, shoots much shower than set from the factory; I get around 120 good shots from it before it starts dropping off. After that it's a click up every two shots....

Your string looks real good, keep in mind as your gun wears in it will get even better. The bolt will also get smoother.

PM sent about a regulator, (He does not plan to use it for Sporter class competition)

Thank you very much. Will start adding a quarter turn to hammer till I get 100 shot with 4% or less deviation. Then will shoot my 70 shots strings with no worry. I was under the impression that I should be at 550 or better FPS.

EJB123 wrote:

Andre wrote:The ideal string is......consistent. Doesn't matter if your shooting 400 or 599 (600 is the limit) because although the length of time the pellet is in the barrel increases with slower velocity, it's so little with decent follow through it shouldn't matter. I backed the power adjuster out on my mechanically stock challenger, shoots much shower than set from the factory; I get around 120 good shots from it before it starts dropping off. After that it's a click up every two shots....

Your string looks real good, keep in mind as your gun wears in it will get even better. The bolt will also get smoother.

PM sent about a regulator, (He does not plan to use it for Sporter class competition)

Thank you very much. Will start adding a quarter turn to hammer till I get 100 shot with 4% or less deviation. Then will shoot my 70 shots strings with no worry. I was under the impression that I should be at 550 or better FPS.

If you need to say raise the shot count by 20, I'd start with two turns. There are no real factory standards, but there are no ill effects if you crank on it. CCW to increase shots, CW to decrease shots.

PM sent.