I will locktite and see how it goes. This is my first year doing FT, so I started at the end of our summer here in NZ, shot through winter and now things are starting to warm up again a bit so wondered if that made much difference. I also might renew the breech seal as there is a bit of fluctuation in fps. It's been tuned to 12ft/lb. The variations seem to be mainly at 30+ metres so wonder if the lower power magnifies any problems.
Anyway thanks for your help. Hopefully I get it sorted for the worlds here in NZ next year.