I recently purchased a box of Horn. Interlocks 130 Gr in .270 caliber. The position of the crimping grooves, measured from the base of the bullets, vary between the bullets with as much as 3mm. Is this normal? I am worried that this will affect the accuracy of the bullets? Can any one give me some advice?

3mm seems like a lot. Have you contacted Hornady. They'd be glad you did. You should get a finders fee. Nice new box of bullets? Or do companies do that any more?

JohanW;
There shouldn`t be any noticable variation in the position of the crimp grove from the base in a box / lot of bullets, definitly not 3mm worth. That is about the variation one would expect between a 130 gr and a 150gr bullet from base to cannular. These were from a new unopened box? I`d weigh a few to make sure they`re the same wgt and in any case I`d give Hornady a call.

Joh: I suspect you meant .3 mm? I haven't worked much with Hornady's, but I completely gave up on bulk Remington and Winchester bullets due to the variations in crimping grooves.

This variation is a big problem if you actually need to crimp, but may not effect your ammunition much if you do not crimp. I NEVER crimp rifle ammunition unless for use in an autoloader which feeds rough or a tubular magazine.

JOHANW,
The only time I've ever observed a difference in the location of the cannelure was actually a difference in case length, not in the cannelures. I have only observed this in pistol ammo. It caused me to trim pistol cases to be used in matches. Good luck.