Home Forums Hunting & Shooting Hunting Rifles Redding NK Bushing Die ???

At the risk of sounding really dumb, I need to ask a question about loading.
Do you guys always use the expander ball when sizing using the Redding NK Bushing dies? Seems pointless to use the bushing and then pull it through the expander. Anyone using a two step NK sizing process where you remove the expander on the second pass through?

I am using the expander. It pushes any inconsistency in the neck wall thickness to the outside leaving the ID a perfect cylinder which is important for bullet alignment on the finished cartridge.

I am using the bushing neck die and the competition bullet seat die. When measuring bullet run-out on a NECO gauge, I never see over .002" and many are less than .001". With those kind of results I don't see the need to change my process.

I have seen expanders on other brand dies induce run-out, but not with the Redding set I am using.

I use the Redding neck sizer competition dies with no expanders. I size no more than .005 inch at a time on the necks, so it takes two passes to get where it should be. Example: A .223 fired neck is .255 inch, so I use a .250 bushing, and then a .245 depending on the brass.

But it the expander is pushing any inconsistency to the outside of the neck, why doesn't the concentricity gauge see it if/when you run the mic on the neck?

I understand you may have good bullet alignment with the inside wall of the neck being consistently round, but I'm not so sure the bushing dies and expander result in pushing inconsistent neck wall thickness to the outside.


Casey

Run-out is a different geometric tolerance from concentricity. I am just measuring run-out of the finished cartridges using the NECO, not concentricity. The NECO is set up to contact the finished cartridge at only one place on the case (near the web) and one place on the bullet (on the full diameter of the bullet just in front of the case mouth) with the indicator touching the ogive. When you roll the cartridge you are just getting a measurement of how straight you put the bullet into the case. The neck OD may be out of concentricity but it is not being touched or measured in this setup. If the ID of the neck was very round and very straight before you pressed in the bullet you will see very little bullet run-out with this measurement.

Without a doubt concentricity of the OD of the neck is important, but the run-out measurement is is much as I am willing to do for my hunting rifle.

Another reason I am not looking at the neck OD is that I am using Norma brass and it is unbelievably consistent in regards to very low neck wall thickness variation (ID to OD concentricity)

BTW I don't think anyone is doing wrong if they skip the expander. My cases are so good I could probably do without it as well. My only point is that my loads are shooting so good I do not believe that tweaking my process is going to yield any more accuracy in my light weight hunting rifle.