There has not been much information about the Kral Bigmax, so I thought that I would share my experience with it...
While the efficiency isn't great, I've been making slow but steady adjustments to my .22 Kral Bigmax. Here is my latest shot string from a few days ago:
(Full-sized image)
This is how it came out of the box (slightly shorter 84-shot string)
(Full-sized image)
In a nutshell I have de-tuned it slightly (32.5 fpe down to 31 fpe on average) by snipping 3mm from the hammer spring while increasing the fill pressure slightly. The ES percentage at the higher FPE was still not bad at just under 3%, but I'm super-happy with 90 shots at just under 1.7% ES. While the poor efficiency does bother me, I do have a shoebox compressor now to fill the 850 cc air capacity ;-)
I'd call the accuracy decent but not outstanding. Here are some typical groups at 63 yards on a less-than-optimal day. I was testing point of impact changes from the end of one fill (low pressure) to the beginning of another fill and found there was not much difference:
While the efficiency isn't great, I've been making slow but steady adjustments to my .22 Kral Bigmax. Here is my latest shot string from a few days ago:
(Full-sized image)
This is how it came out of the box (slightly shorter 84-shot string)
(Full-sized image)
In a nutshell I have de-tuned it slightly (32.5 fpe down to 31 fpe on average) by snipping 3mm from the hammer spring while increasing the fill pressure slightly. The ES percentage at the higher FPE was still not bad at just under 3%, but I'm super-happy with 90 shots at just under 1.7% ES. While the poor efficiency does bother me, I do have a shoebox compressor now to fill the 850 cc air capacity ;-)
I'd call the accuracy decent but not outstanding. Here are some typical groups at 63 yards on a less-than-optimal day. I was testing point of impact changes from the end of one fill (low pressure) to the beginning of another fill and found there was not much difference: