7RUM CRIMP OR NOT

[Varmint Hunter]

I do not crimp any of my reloads except for the 45-70. I have experimented with crimping Hammer bullets because of the minimal bearing surface in the neck with their bullets. In direct comparison with Hammer reloads with, and without, crimp; I found that the results varied. I have concluded that you can't just assume that crimping will always improve your accuracy. There was also an "assumption" that magnum primers always improved Hammer reloads but that has been disproven by many loyal Hammer users.

The fact is that all rifles are different, and components vary widely from reloader to reloader. It's difficult to predetermine the effects of various changes without actually trying them on paper. My recommendation would be to try your reloads without a crimp first and if unsatisfied then you can try crimping to see how it effects the group.

 

[valleysnyper]

I am using hammer bullets now, maybe I'll try it both ways and see the results

 

[Varmint Hunter]

I am using hammer bullets now, maybe I'll try it both ways and see the results

I'm guessing that you are already having satisfactory results. I would be most interested in your results when testing both ways. If you have a chronograph; checking the difference in SDs would be helpful too.

There "may" even be a noticeable difference between crimping on the crest of a PDR compared to crimping in one of the grooves. Shooters seem to prefer one or the other. Just another variable to make the game fun.

 

[ButterBean]

I crimp everything

 

[whirlwindjml]

Here is my 200 yd group, just wondering about crimp because of amount of recoilView attachment 413747

I would put that in the win column and go huntn

 

[Bob Wright]

It's not an expensive die to try. It helped my 7RM and 280AI extreme spread settle down.

 

[Creedmoor shooter]

I dont crimp anything. I think as long as you have proper neck tension consistency then you're fine. Moving to an expanding mandrel set up is the best thing I've ever done for resizing.

 

[cape cove]

I tried crimping in my 7/08 with the Lee FC. I took my best 7/08 load and crimped it and accuracy went south. I don't believe the problem was the crimping but the fact that I didn't work the load up using crimping at every powder and seating depth level. No doubt crimping will affect the start pressure and velocity changing the OBT of the load. I assume that was the reason. I may in the future work up another load using crimping at all nodes to see if it improves the accuracy. JME

 

[Varmint Hunter]

I tried crimping in my 7/08 with the Lee FC. I took my best 7/08 load and crimped it and accuracy went south. I don't believe the problem was the crimping but the fact that I didn't work the load up using crimping at every powder and seating depth level. No doubt crimping will affect the start pressure and velocity changing the OBT of the load. I assume that was the reason. I may in the future work up another load using crimping at all nodes to see if it improves the accuracy. JME

It would be very enlightening to see the results of such testing. Best load with crimping vs best load without, even if the loads are different.

 

[Creedmoor shooter]

It would be very enlightening to see the results of such testing. Best load with crimping vs best load without, even if the loads are different.

Id like to throw in mandrel sizing too. I think thats what most competition guys do as far as I know. I've not heard of any of them crimping. If I'm not mistaken the purpose of the crimping in this case is for my consistent tension on the bullet correct?

 

[ButterBean]

I dont crimp anything. I think as long as you have proper neck tension consistency then you're fine. Moving to an expanding mandrel set up is the best thing I've ever done for resizing.

That horse has been beat to death, if it works for you by all means stick with it, with that being said The Lee FCD used properly ( don't follow the LEE instructions)will always help and is a very instrumental load tuning tool

 

[Creedmoor shooter]

That horse has been beat to death, if it works for you by all means stick with it, with that being said The Lee FCD used properly will always help and is a very instrumental load tuning tool

I didn't say it wouldn't help in some cases. But as mentioned above in other cases it didn't help. As long as you have a method of keeping neck tension consistent then it doesn't matter which method you use.

 

[ButterBean]

I didn't say it wouldn't help in some cases. But as mentioned above in other cases it didn't help. As long as you have a method of keeping neck tension consistent then it doesn't matter which method you use.

You missed the key words " if used correctly "
As I said if it's working for you then stick with it but your method has been engrained in our way of thinking for eons, does it work, Yep, but so does the FCD used correctly
As far as you statement that it doesn't matter…. To me it does, I have had and seen bullets move from everything to airline trips to the magazine beating them back, I personally will not take that chance

 

[Creedmoor shooter]

You missed the key words " if used correctly "
As I said if it's working for you then stick with it but your method has been engrained in our way of thinking for eons, does it work, Yep, but so does the FCD used correctly
As far as you statement that it doesn't matter…. To me it does, I have had and seen bullets move from everything to airline trips to the magazine beating them back, I personally will not take that chance

I'm not sure why your singling me out but I'm not going to fight with you about it. The man simply asked if crimping was necessary and it's not. Lots of people shoot really small groups without it.