Question: RE: Crimping match loads

[rduckwor]

I have a shooting friend who is a bit of an inventor/tinker and a pretty smart guy.

He recently emailed me about the fact that he had rigged a torque wrench to his SS press and was seating and "crimping" to set forces.

The seating part, yeah, maybe that's a good idea. However, I had always been taught that one does not crimp a bullet without a cannelure.

I understand the purpose of crimping to avoid bullet setback in auto loaders.

Does it play any role in developing and maintaining consistent neck tension as well for the typical bolt rifle loads? He is not neck turning to my knowledge.

Thanks,

 

[GhostFace]

I crimp regardless of semi or bolt using a Lee FCD. I think a light taper crimp keeps pressures consistent. All factory match ammo has crimp and its accurate as all get out so why wouldn't work for us?

 

[velillen]

For semi auto's I do .002-.003 of a crimp whether it has a cannular or not. Revolvers get a bit more but not much.

Bolt actions I dont crimp at all. I tested my load with and without crimping and didn't see any change personally

 

[joemusso]

i do the same thing i crimp semi auto's and pistol but not bolt actions.

 

[Temp9]

In my experience, any crimp on a non-cannelure bullet that isn't enough to deform the jacket also isn't enough to make a difference in neck tension. Likewise, if you crimp enough to see an increase in neck tension, you've deformed the jacket. You may notice a slight decrease in SD, but you will probably notice a slight decrease in accuracy, as well.

I only crimp for semi-autos running cannelured bullets.

 

[leadbullet]

i use a neck bushing die to slightly under size the neck, this will create uniform tension on the bullet on the whole neck of the case. then I don't crimp.

 

[Rob01]

In my experience, any crimp on a non-cannelure bullet that isn't enough to deform the jacket also isn't enough to make a difference in neck tension. Likewise, if you crimp enough to see an increase in neck tension, you've deformed the jacket. You may notice a slight decrease in SD, but you will probably notice a slight decrease in accuracy, as well.

I only crimp for semi-autos running cannelured bullets.

What he said. Neck tension holds bullets just fine.

 

[thrusty]

+1 here - crimp autos only. If you use a bushing die that gives you even more ability to adjust your neck tension in the bolt guns....it's always worked well for me that way...no crimping necessary in the bolt guns.