JSB Jumbo Express. 22 in Sumatra Carbine.

[Froggy.]

I usually shoot 18gr jsb's in the sumatra, but since these were the only jsb's in stock at my local gun shop I bought a tin to try.. 5.52mm

De- tuned sumatra carbine... Velocity set to 910fps.
5 shot groups 44 yards no wind.
Flyer top left was the first shot of a 6 shot group.

 

[Froggy.]

Picture of pellets shot into a blanket at very low velocity to inspect the rifling engraving.
JSB 18gr on the left and 14.35gr right.

 

[carlhall]

hi Froggy

I am new to PCP rifles.I am going to get myself the same (Sumatra .22 Carbine) also with one of your LDC. 

Is there any other work you can do to it to improve it.

Regards

CARL