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New neck expander/bullet tension/accuracy

FL sizing the necks, bullets are 55 FMJs, 69, 77, and a few 80s BTHPs, seating according to each type, mostly mag length. I don't leave em hanging so to speak.
So you FL size necks and don't know how much bearing is in or through necks?
I don't see how anyone could guess about your tension.
 
I don't shoot the AR platform, not since I was in the Army in the early 70's so my remarks are relative to my experience with several 223 Rem precision bolt rifles.

I won't comment on the suggestions already offered but I'll share my thoughts and experience on the use of expander balls.

I full length resize all my cases for all my rifles. I do not turn necks. I use a standard RCBS full length sizing die for sizing. I've found that the standard RCBS expander balls are too large, tend to stretch the necks and over work them. Thus I lean towards more neck tension rather than less (i.e. small diameter expander balls.)

The appropriate size expander ball varies of course between brands of brass, age of brass, and rifle. I do not like an expander ball that has too much drag on the neck of the case that can stretch the neck or over work the neck. According I have several expander ball / depriming assemblies of different diameters. I use the one for a specific lot of cases / rifle that expands the neck with the least drag on the neck but expands the neck slightly for a uniform concentric neck. I've found that a least in my rifles, this produces the most uniform groups.

It's quite easy to make a series of expander ball assemblies with different diameters. Just chuck the assembly in a drill, lock in a vice, and polish with fine emery cloth a little at a time until you obtain the desired diameter. This also polishes the ball producing a "glass" like finish making it pass through the neck smoothly without having to lube the inside of the neck.

Also I use a rubber O ring under the assemble lock nut so the expander "floats" thus minimizing run out.
 
Many reloaders use the Lyman type "M" expander for their AR15 rifles and bump the case mouth onto the .226 section. This aids straight inline seating and reduces neck/bullet runout. If needed a taper crimp die can be used to close up the case mouth for proper feeding. Normally after brass spring back the case mouth is only .001 larger than bullet diameter. My main point being the Lyman expander is .221 and .003 smaller than bullet diameter.

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Below is from a test of .223 resizing dies and how much they work the brass, And you can see the inside diameter of the case neck using the expander and the amount of bullet grip.

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And below the RCBS AR Series dies come with a taper crimp

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What!?......... no mention of of the great Forster F/L sizing die Ed?.....Bwahaha!...
Wayne
 
Thanks Ed!.... I needed that fix I haven’t heard how great they were for almost 24 hours and started to forget!... but now I’ve been reedgumacated!.....thanks buddy!
Wayne

If you liked that fix, then here is a giant overdose................:)

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My wife loves her Forster also. ;)

M4Y_000.jpg
 
Why not chunk the expander? I don’t think it matters what size bushing you use if you are pulling an expander back through your necks. The mouth is going to be the size of the expander less the spring back(.001 or so)
If you want to open the neck after sizing, use pin gauges.
 
The Redding bushing die FAQ tells you if do not neck turn and the neck thickness varies .002 or more to use the expander that comes with their bushing dies. ;)
 

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