i have a 177 cal 52 and i put a monolith spring 142 wire id 580 plus 30 coils oal is 11.5 i also replaced the breech seal everything else is stock. oh but i did fix the cocking problem and debur it. also i lubed the gun. but i think the volicity is low at 25 yds with cp 10.5 im getting 683.8 655.4 662.5 668.4 674.8 and with kodiaks at 25 yds 713.0 698.3 704.4 698.9 691.4 what gives can anybody help. thanks in advance airitout.
check the breech seal is not squashed/damaged or not seated squarely in its hole.
Then check that the cylinder and cocking arm relationship is as it should be, that is;
there should be a slight outward bowing of the cocking arm rod after the gun is cocked and the cocking lever returned to the closed position.
This indicates that the cylinder is firmly pushing the breech seal against the barrel and thus eliminating any losses here.
If after this it is still lacking power, you'll have to take a look inside then and do not overlube.
If everything checks out OK, I would put the old spring in to check and see if the Monolith is causing the problem.
You didn't mention if you have the fitted JM guide and top hat or got custom ones made, or just put it in. If the latter, the spring fit on the stock guide could be an issue.