Quick update after another trip to the range...

I had a hunch that the barrel itself may need a good 'heat cycling' (for want of a better word...) to settle down, which worked on a previous SMLE No 4 Mk 1 I owned.

So rather than s-l-o-w-l-y shoot my group, waiting for the barrel to cool down between each shot I shot a rapid 5 shot string (the light barrel got VERY hot) then fired two 5 shot strings using Remington 180gr factory ammo.

This was the same ammo batch as the one which produced pronounced vertical stringing as the barrel heated up.

Each 5 shot string was fired with the barrel sizzling hot (not good practice I know, but necessary for this experiment...)

Look at the groups produced... no change to bedding, fore-end pressure, hold position or benchrest equipment