crimping rifle cartridges?
 

Just getting started with handloading for rifle cartridges, after many years of using a Dillon for pistol ammo. Now I have a Lee single stage and am playing with .223 and 6.5 grendel.

Books I've read have suggested that a crimp is unecessary (and the Lee die instructions flatly state not to do it unless you have a bullet with a cannelure). Both of these cartridges are going into AR-15 style rifles. (Maybe someday I'll start .30-06 for my garand, but not yet)

Do you guys crimp?

For rifles, only on bullets with cannelures.

TR

Rich:

Most don't crimp for the rifle as in most cases it isn't necessary. I don't crimp even if I use a bullet with a cannelure. If you are using the Lee 6.5 G die set, it comes with a crimping die and some guys say it gives them more consistent velocities and accuracy. Most likely it will also wear out the necks faster and if used with a bullet that doesn't have a cannelure it will put an indentation into the bullet if not set perfectly on the press.

Probably the best route is to use a sizing die that uses neck bushings of various sizes so you can find the right bushing to give you good neck tension when seating. Such a set up will give you much longer brass life and also eliminate a need to crimp. Although I haven't found a bushing die to be a necessity for .223, I believe it is a necessity for the 6.5 G. Redding makes them.

GE

Depends on whether the bullet has a cannelure; sometimes not even then. I used to load a lot of "trash" ammo with MILSURP pulldown bullets. I always crimped them because they were for blasting at short range and the accuracy issues associated with crimping were not a factor. Lately I've been loading mostly long(er) range ammo that I never crimp. The more you know, the more "depends" sounds like the reasonable answer.

If I remember correctly, crimping bullets was for the same reason as crimping primer pockets. The shock of full auto fire. I see no real reason to do so.

My understanding it is about inertia energy from recoil. Other aspect of a crimp is case length. Cases need to be of the same length or pressures will vary. It also effect chamber pressure by increasing it. Definitely not needed on single shot firearms and low recoil types.


BTW, Lee's factory crimp die is a great bargain for the money.