OzFclass

Will cases that close tight in the chamber affect my shot?

Not if they are all the same
you may want to consider shoulder bumping a few thou
the next level of this is they will become hard to extract
RB

Cheers, I've been having a few wild shot over the past few weeks, like going from a good group in the x and 6 to a high 4 or a low 5. These shots only seem to come on loads that are a little tight to close in the chamber. Going to try completely new brass and see if that will change it at all.

The key is uniformity with every single thing.
Good Luck
RB

Cheers for your advice mate I've been shooting for a while but am only just getting into f class and am really enjoying it.