neck size bushing for 220/6mm beggs

ndh78

New member
I have the bug to start shooting some more and am planning to build myself a new rifle. I want to use the beggs cartridges in both 220 and 6mm. What I am wanting to do is make my dies without neck bushings and try and reduce loaded round run out. So my question is without having much first hand experience what it the preferred neck size bushing. I will be using .269 neck on the 6mm and whatever the specified size is for a fitted .220 neck. I understand that some tune by neck tension but I will be using powder and a tuner for that. I also understand bullet size may come into play here so a suggestion on bullets would be ok as well. I do know that I will use barts for the .220.
 
I have the bug to start shooting some more and am planning to build myself a new rifle. I want to use the beggs cartridges in both 220 and 6mm. What I am wanting to do is make my dies without neck bushings and try and reduce loaded round run out. So my question is without having much first hand experience what it the preferred neck size bushing. I will be using .269 neck on the 6mm and whatever the specified size is for a fitted .220 neck. I understand that some tune by neck tension but I will be using powder and a tuner for that. I also understand bullet size may come into play here so a suggestion on bullets would be ok as well. I do know that I will use barts for the .220.


The bushing type sizing die made by Hornady for the Beggs cartridges produces good, straight loaded rounds. In my opinion, nothing can be gained by making your own, custom, fixed-neck sizing die. For the 6mm Beggs with the .269 neck, use a .2660 carbide bushing and keep a .2655 handy if neck tension gets a little light. Turn the necks to .0120.

For the 220 Beggs with .250 neck, use a .2480 carbide bushing and keep a .2475 as a backup. As with the 6mm, turn case necks to .0120.

It has been my experience that loaded round runout of up to .002 TIR has no effect whatsoever on accuracy. Loaded rounds sized in the Hornady die with bullets seated with a Wilson straight-line seater typically result in .001 TIR or less. It sure is handy to have only the one sizing die to size both the 22 and 6mm Beggs cartridges by changing only the neck bushing.

Once optimum seating depth and neck tension is established, all tuning is done with either the powder charge or if installed, a Beggs tuner.

As far as neck tension and seating depth is concerned, I have found that light to medium neck tension is the way to go and this can only be determined by feel.

Once you have settled on a neck tension that feels about right, "jam" is established with that tension. Begin testing with the bullets seated right on 'jam' and back them off .002 at a time until horizontal dispersion disappears. Then and only then tune the vertical out with the load or tuner setting. Remember; tune the horizontal out first, with neck tension and seating depth, then, tune the vertical out. :)

Have fun. Let me know if I can help.

Gene Beggs
 
Well I understand that the tir is kind of trivial but its just something I wanted to do, it won't cost me anything but a little time and I'm finally getting caught up so I can work on some of my own stuff. I have the die blanks sitting there and I can always knock the the neck out and switch them to a bushing later if I want.
 
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