Quote Originally Posted by 45flint View Post
I do think you are probably onto the issue. I know I read BB Pelletier review many times and if you look at his rifle it is really well used and not in great shape, even missing the barrel spacer. I have never felt any air puff out on firing and my lockup is pretty secure. My rifle though used is in very good original shape. But since you asked the question I thought I would further test it by laying a tissue over the top of the breech and yes it hopped a small bit (1/4 inch) with some oil on the tissue when I fired with 6 pumps. So my breech is not totally locked up either. I suspect that it just locks up better than yours and Pelletier’s? I could put some of my newly acquired damping grease around the probe and see if I get a total seal? I will try that this afternoon. This could explain why a professional reseal only went so far to give you your performance. I doubt any pro on a reseal would rework a breach seal that is metal to metal. Crosman like Sheridan would soon add a O ring to the probe to fix this potential issue.

By the way I tested Hobbys in my rifle the other day as well and like you I saw a very modest increase in speed. I think common wisdom is heavier pellets are better in pneumatics: seemed to hold true. In my spring powered gun they can really make a difference.
Very interesting. As my 108 is not 100% original anymore, it might (might...) be interesting to machine the bolt to use an o-ring.
Ped springs to mind immediately for an interesting job like this haha.