Quote Originally Posted by enfield2band View Post
They reckon that because the rifling on the .577" Enfield is only about .003" the bullets are not setting up in the rifling because the barrel has expanded enough to stop the bullet setting up in the rifling.
Excepting the earliest Patterns, Enfield rifles had progressive depth rifling, the P.53 for example being 0.015 deep at the breech and 0.005 at the muzzle. Parker-Hale used progressive depth rifling on their reproductions. So, on firing, the bullet expands to fill the deeper rifling, and is then swaged a little as it travels down the bore.

One variable creeping in as the summer months come and temperatures warm is the lube they are using. It may perform better in cooler temperatures? It could also be something external - do they always shoot on the same range; perhaps height of the sun and light and shade on the sights or target is detrimental to accurate shooting in the summer? Maybe the shooters themselves shoot better in the spring and autumn - are they wearing the same thickness clothing year round?

Lots of variables to consider... just a few passing thoughts.

David