I have four Lee Enfields and they all have quite oversize bores. I use the NOE 316299 sized to 0.315" and the NOE 0.314" x 129 gr. lapped to 0.316" again sized to 0.315". Both just fit into the throat at 0.315"+ and give good accuracy.

Check throat diameter and pick a size that will just fit. That is what worked for me anyway.

Longbow