Reading this reminded me of the time I fettled a 'project 77' a few years ago. I fitted a new spring (not a HW one) and guide ... the spring had a lot of preload and was a b****r to fit and just about coil bound with no preload washers at all. The result was disappointing at c. 10. So I bit the bullet, as it were, and removed said spring and with heart in mouth removed a couple of coils. The spring was easier to fit and the power increased to c.11. Another coil was added to the bin and I ended up with a rifle running nicely at c. 11.5. This was in .177 Memory fails me and I may have missed a spring shortening stage as I now think that at one point I went OTT ... but whatever, to get the rifle shooting nicely I had to remove coils.
So, while I am not suggesting your rifle may be oversprung, it is worth considering.

Cheers, Phil