is it better

[Bruce_in_Oz]

Neck crimping can have a couple of advantages, and one disadvantsge:

1. As noted by CINDERS, it helps prevent the projectile being displaced during "vigorous" feeding.

2. It DEFINITELY helps with combustion consistency, and thus muzzle velocity consistency, especially in rifles that have the typical long "military" throat, esp .303Brit.

The only REAL disadvantage is that it "works" the brass at the end of the neck. Thus, and especially if you do not regularly anneal case necks, the necks will start to split somewhat sooner than otherwise.

The Lee dies are capable of applying so much force that the "crimp" can also form a cannelure on the bullet. This does not seem to adversely affect accuracy.

I run "factory crimp" dies for .308, .30-06, 7.5 Swiss (essential for model 1911 rifles and carbines), .303 and 7.62 x 54R.

They are a boon to those lucky enough to be still able to run semi-autos. Those reloading for MGs should ALWAYS use such dies; much cheaper than having to strip and clean the toys on the line after a bullet gets rammed back into the case.