Cricket .25 accuracy problems

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Hi , last time I shot my cricket it seemed to be inaccurate . Today I decided to find out the problem. First I clean the barrel , which was a bit dirty , until the patches were almost white. then I check the scope mounts , cant , tighten all the screws ( except the screws holding the barrel , they are under the scopes and are Loctited). I suspected the moderator to be the culprit , so I shot 11 pellets , JSB 25,39gr at 880 Ft/s without the mod and here are the result ( the 5 shots under the tapes were shot with the moderator on ).I can't explain such a dispersion ; shot string was between 872 Ft/s and 883 Ft/s , so the reg works properly. Was the velocity too high? I didn't try to decrease it. If somebody has an idea to fix this issue , just tell me . Thanks
 
.25 cal pellets have about a 850 FPS max velocity before they start getting inaccurate. I shoot 25.4 grain JSB Exact King pellets around 820-840 FPS depending on air pressure in my BSA Lonestar .25. A moderator increases speed by about 20 FPS, so if you are slightly over max accurate velocity, removing a moderator can increase accuracy. Try reducing your velocity a bit below 850 FPS and see if that helps. If not, you probably have another issue to resolve. Some rifles may not like JSB pellets, although I find they are the best in my rifles.

Understand that altitude has an effect on maximum accurate speed. I shoot above 3000 feet elevation. At sea level you may have to reduce velocity a bit below what I am shooting at. I would reduce velocity to 800 FPS and increase from there until I found at what velocity accuracy suffers, then back off a bit.
 
Scope is a Hawke Sidewinder , but I'll probably put another one just to see , and at the same time check the grub screws holding the barrel . When I shoot the gun , most of the time the 4 or 5 first shots are grouping very well , and then the group moves sideways or below the first one. Difficult to know if the barrel is the problem without trying another one.
 
I saw a video from Ernest Rowe on how to install the barrel back on the Cricket ; I made maybe two mistakes : I torqued too hard the grub screw which indexes the barrel to be sure the transfert port holes are in line , and didn't follow the torquing sequence of the four screws clamping the barrel.

Maybe this could help , unfortunatelly it was too late in the evening to test the gun . If this doesn't work 'll swap the scope......or put an order for the Kalybrgun Argus 60 😁
 
It should not be pellet speed the 885 fps is what i tune both the 22 and 25 to. I've had an Ernest tuned 25 to shoot at 885 with the 25's. My current gun is tuned to do the same with the 33's. That gun shoots the. 25's at about 990. At 73 yards it will hit 1" Christmas balls with both pellets. Maybe you clipped the baffles with a double load. Using Grizzlies or Polymags pellets are all over the place, and the accuracy is not there without the shroud.