There were zillions of student trials and tests between two groove and 5 groove barrels and there really was no difference between the accuracy of either that could be put down to the rifling. It was said that the two groove barrels stayed more accurate for longer for various proven and unproven and even mystical reasons. Some could be described as simply magical reasons judging from the way some papers were written!

It really is all about imparting gyroscopic effect to the projectile plus the foibles of .........., well everything else on the particular day in question really!