crimping and my exsperence

[misser]

after turning the necks ,to about 15 thousands , I found my accuracy had wain'ed . got it back by crimping just a touch. is that odd ?

 

[Uncle Ed]

All your crimping is doing is increasing neck tension or bullet grip. You could do the same by decreasing the neck diameter either by a smaller bushing or reducing the expander diameter.

Example below, many AR15 reloaders expand the neck with a Lyman type "M" expander with .003 neck tension. And the RCBS AR series dies have a taper crimp and the is more for smooth feeding by streamlining the case mouth.

And Lee makes undersized pistol dies to increase bullet grip and prevent bullet movement during recoil and feeding. No one anneals pistol brass and with mixed range pickup brass the undersized dies work very well.

And Whidden dies sells expander kits with five expanders from bullet diameter to .004 under bullet diameter.

 

[Richard Coody]

Obviously you have a problem with consistent neck tension. The crimping is making it more.consistent. there are much better ways to accomplish this.

I only crimp pistol rounds.

 

[misser]

I had not thought about reducing the expander . which would likely work better seeing I seldom use bullets with cannelure

 

[Rsadams]

I crimp my AR .223-556 stuff but I don't use a crimp in my bolt action rifles. What ever works for you is good....

 

[AJC]

sounds like you need to jump in the boat with me and buy a set of the new 21st century mandrels. If you have bushing dies then just go smaller.

 

[misser]

I dont yet know how to test how much neck tension this gun needs . or if there is a test or way to prove it. more seems better

 

[AJC]

In the book metallic cartridge reloading the author claims that neck tension is the only way to increase bullet pull and a crimp cannot increase that amount and done incorrectly can decrease total pull. Using different size bushings or mandrels would be how I would test. Thicker necks would normally increase tension and brass hardness would be the other factor. If you anneal every time for consistency then hardness should be a near constant. He goes on to say you can work your brass in a die a few times to increase hardness. This will decrease life a little imo.

 

[misser]

I will disagree with said author

 

[misser]

All your crimping is doing is increasing neck tension or bullet grip. You could do the same by decreasing the neck diameter either by a smaller bushing or reducing the expander diameter.

Example below, many AR15 reloaders expand the neck with a Lyman type "M" expander with .003 neck tension. And the RCBS AR series dies have a taper crimp and the is more for smooth feeding by streamlining the case mouth.

And Lee makes undersized pistol dies to increase bullet grip and prevent bullet movement during recoil and feeding. No one anneals pistol brass and with mixed range pickup brass the undersized dies work very well.

And Whidden dies sells expander kits with five expanders from bullet diameter to .004 under bullet diameter.

I turned the expander diameter down just a bit as you suggested . seams to have worked