Crimping required on cannelure bullets? Still learning the ropes

PersonalBurgers

PersonalBurgers

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Just curious if crimping is required when seating bullets with a cannelure? Recently got a batch of .224 FMJ 55gr BT and I wan't to start loading some tonight! Just a little apprehensive about the crimping thing.

Any input is appreciated! :wave:
 
If you are shooting a semi-auto, crimp.
If you are shooting a bolt action, crimp is not necessary. Some guys crimp anyway, but waste of effort imho.
 
My RCBS AR Series .223/5.56 dies have a taper crimp die, this makes it easy to apply a light crimp around the cannelure of the bullet. I also polish my expanders and they end up slightly smaller in diameter but have much less drag in the case neck.

Below is a Lyman type "M" expander for a .223/5.56, please note the .221 part of the expander is .003 smaller than bullet diameter. The upper part of the expander is .226 and you just bump the case mouth onto this step to help start the bullet straight in the case neck. And with brass spring back this section would only be .001 larger than bullet diameter.

My point being this expander is .0015 to .002 smaller in diameter than a standard expander in a die set. And will increase bullet grip-neck tension, many people with a progressive press use this expander and do not crimp because of the added bullet grip. Or if you want you can apply a slight taper crimp to streamline the case mouth for smooth loading in a AR15.

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Note, at the Whidden custom die website they sell expander kits with five expanders. The expander diameters go from bullet diameter to .004 under bullet diameter. These expanders allow you to control the amount of neck tension that can vary with brass hardness and brass spring back after sizing.
 
Semi, lever with a tube, or hard recoiling cartridge I like to crimp. I'll also crimp light bullets when used in larger cases like a 110gr pill in the 7RemMag, helps with ignition.
For crimping there is only one tool... Lee Factory Crimp Die.
 
Crimping in many cases actually helps with accuracy. I've done the test many times. Don't presume right off the bat that crimping hurts accuracy.

If you're taking your neck tension into consideration by using bushing dies, turning your necks, etc. then I'd avoid crimping.

Cheers.
 
PersonalBurgers said:
Just curious if crimping is required when seating bullets with a cannelure?
Click to expand...

The question is a straightforward yes or no type, not sure why everyone thinks the answers leave so much room for interpretation?

No, crimping is not required. The cannelure is there so that if your load requires crimping, there is a convenient place to do so. But the bullet does not need to be seated with the cannelure at the case mouth, and it doesn't have to be crimped. It is entirely up to you and your gun.
 
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