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Half neck sizing

chamberbrake

Forward Forever Backward Never
Minuteman
Apr 23, 2020
64
7
www.chamberbrake.com
I use a bushing die in a FL resizer. I randomly loaded a few rounds with only half the neck in the bushing. I fired them and they turned out to be my best loads to date. Any thoughts on this being something others have done with success?
Thanks
Aaron
 
Lots of people have done it. Just another tool in the bag, another variable to test and chase down.

Now, would sizing half the neck be better and more consistent than sizing the entire neck slightly less in diameter? How do those 2 variable play together? Now all of the other variables.

Article on bullet grip


"Bullet grip is affected by many things, such as:
  • 1. Neck-wall thickness.
  • 2. Amount of bearing surface (shank) in the neck.
  • 3. Surface condition inside of neck (residual carbon can act as a lubricant; ultrasonic cleaning makes necks “grabby”).
  • 4. Length of neck (e.g. 6BR neck vs. 6BRX).
  • 5. Whether or not the bullets have an anti-friction coating.
  • 6. The springiness of the brass (which is related to degree of work-hardening; number of firings etc.)
  • 7. The bullet jacket material.
  • 8. The outside diameter of the bullet and whether it has a pressure ridge.
  • 9. The time duration between bullet seating and actual firing (necks can stiffen with time).
  • 10. How often the brass is annealed
— and there are others…"
 
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Lots of people have done it. Just another tool in the back, another variable to test and chase down.

Article on bullet grip


"Bullet grip is affected by many things, such as:

  • 1. Neck-wall thickness.
  • 2. Amount of bearing surface (shank) in the neck.
  • 3. Surface condition inside of neck (residual carbon can act as a lubricant; ultrasonic cleaning makes necks “grabby”).
  • 4. Length of neck (e.g. 6BR neck vs. 6BRX).
  • 5. Whether or not the bullets have an anti-friction coating.
  • 6. The springiness of the brass (which is related to degree of work-hardening; number of firings etc.)
  • 7. The bullet jacket material.
  • 8. The outside diameter of the bullet and whether it has a pressure ridge.
  • 9. The time duration between bullet seating and actual firing (necks can stiffen with time).
  • 10. How often the brass is annealed
— and there are others…"
Thanks, good article.
 
I use a bushing die in a FL resizer. I randomly loaded a few rounds with only half the neck in the bushing. I fired them and they turned out to be my best loads to date. Any thoughts on this being something others have done with success?
Thanks
Aaron

One of the competitive shooters I know leaves a significant amount of the neck shy of the bushing. He believes that the portion of the neck that goes unsized and therefore stays wider serves to better align the bullet in the barrel.
 
I too, have read that the partial neck sizing is believed to help align the case in the chamber. I'd say, trying both partial, & full neck sizing is worth trying...
 
So what about the shoulder? Are you not bumping it back?
If you are using a full length bushing die you can still get the desired shoulder set back as thats in the die body which's depth is controlled by the external lock ring. To partial neck size you just dont screw the bushing plug down as far into the die body which lets the bushing lift up inside to the desired location freely.
 
If you are using a full length bushing die you can still get the desired shoulder set back as thats in the die body which's depth is controlled by the external lock ring. To partial neck size you just dont screw the bushing plug down as far into the die body which lets the bushing lift up inside to the desired location freely.

Yes this is what I did.
 
I did this with some br brass that I found grew quite a bit fireforming bra, like .012”! So I decided to not bump the shoulder and run the bushing about 3/4 the length of the neck. Brass didn’t grow on next firing, just wanted to make sure, and it shot great. But with the length of the br neck I probably had full neck tension on the sized portion I did on the bullet bearing surface.
 
I did this with some br brass that I found grew quite a bit fireforming bra, like .012”! So I decided to not bump the shoulder and run the bushing about 3/4 the length of the neck. Brass didn’t grow on next firing, just wanted to make sure, and it shot great. But with the length of the br neck I probably had full neck tension on the sized portion I did on the bullet bearing surface.
This is what I'm seeing. Seating bullets basically full length but not full length neck sizing. Thanks.