Lancaster oval bored artillery carbines, mates of mine who have used them find they give the odd inexplicable flyer, but that is using minnie bullets. I hope to try one one day with my Enfiled paper cartridges, these are made up with the pritchett bullet and are effectively paper patched. I can shoot these all day without fouling my Enfield rifled muskets, unlike using minnies where I have to wipe out the bore every 13 or 14 shots. I have seen a Lancaster small bore repeating rifle, English made in 6.5mm, for cordite and that was also oval bored, as agains some Canadian Lee Enfields that were just two grooved.