This 1377 is my first crosman lego gun. I have been working on this off an on for a couple years. I never got the power I wanted out of it in .177. It barley hit 600 fps with 7.9gr. So fairly I recently swapped it to .22 with a 12" barrel and extended probe bolt from mellon air. Doing ok now but might still be on the slow side. Still has all oem porting other than the hard 90 degree in the valve being smoothed out so opening that up might help. The mod list is long if any one wants it I can try to remember everything.
I still need to find a decent metal barrel band with a front sight that dose not cost $70, and I'd like to try out a super sear in it. It's quiet, and lighter than it looks thanks to the aluminum breech and carbon fiber moderator. Crosman projects are rarely ever done. I'll post updates to this thread when I tinker with it.
A few shot strings. All shots using 14.3gr CPHP
6 pumps
5 shots
average 438.2 fps
Standard deviation 1.78 fps
6.09 fpe (about what it made on 10 pumps in .177)
12 pumps
5 shots
Average 564 fps
standard deviation 4 fps
10.10 fpe
15 pumps
one shot
596 fps
11.28 fpe

I still need to find a decent metal barrel band with a front sight that dose not cost $70, and I'd like to try out a super sear in it. It's quiet, and lighter than it looks thanks to the aluminum breech and carbon fiber moderator. Crosman projects are rarely ever done. I'll post updates to this thread when I tinker with it.
A few shot strings. All shots using 14.3gr CPHP
6 pumps
5 shots
average 438.2 fps
Standard deviation 1.78 fps
6.09 fpe (about what it made on 10 pumps in .177)
12 pumps
5 shots
Average 564 fps
standard deviation 4 fps
10.10 fpe
15 pumps
one shot
596 fps
11.28 fpe
