Thanks for all the replies guys.
Well ... a number of comments there from guys who I respect that are suggesting this polishing out of this tight spot is a no no. So the handbrake has gone on at the moment and we'll just hang on a bit and have a think.
I'll have look at how long the tight bit is at the breech and have a look at how far in the bolt pushes the pellet etc.
Last edited by skires; 14th January 2016 at 08:19 AM.