Quote Originally Posted by BTDT View Post
It would be nice if all measurements were either imperial or metric, but it's not a huge problem.

Did you test the full 286mm spring with the 3.2mm port before shortening it and, if so, what were the results?
Can't find definitive but fairly confident was above the 3mm TP values below.
268 x 36 lb/inch PL 67 Hobby 7 gn 10.8 fpe , SD 8.3 gn 10.3, Exact 8.5 gn 10.8, Bisley 10.2 gn 9.8.

For info. 268 spring now cut to 250 rate 40.6 lb/inch. Energy still near 11 with exact/express/FTT 9+ with Bisley.
Gone to owner for appraisal. His first shot rang 3/8" bell at 20 yds. standing unsupported.
Can't say shooter or rifle but promising.
Will report back after a bit of bedding in and try to be more diligent with recording data.
Many thanks to everyone.