Chubbs,
You will appreciate its a hard call without the rifle in your hands to see exactly who the culprit is. If I were you and you live in the Midlands area take it into Norman Clarke Gunsmiths 19 Somers Rd, Rugby CV22 7DG
Phone: 01788 579651
On a Friday and Bill Smallwood will be in, ex PH engineer, he will sort it for you I am certain, but it is something that needs to be held to cure!