Neck bushing conundrum

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Hello. Here's a question I hope someone clever can help me with.

A while back I bought a Hornady "New Dimension" full length sizer die for my .223 rifle and, upon the recommendation by Hornady, a bushing for it, size 0.246"

Over the w/end I tried it out for the first time, all went well, until I tried to chamber an empty, sized case into my Tikka T3. The bolt almost fully closed, but needed a bit of a push for the last 1/4 inch or so. Also, when I sat several different bullets into the case neck they virtually fell into the case!

 

Q1. has the sizer opened the case neck out to much, making it tight in the chamber's throat & at the same time making it too slack internally to hold a bullet?

Q2. There are 4 bushing sizes for a .223 Rem. a. 0.242", b 0.244", c. 0.246" (mine) & d. 0.248". So, I kinda know its obvious, but can you confirm I need to go "down" a size, i.e. 0.244" to head it in the right direction and make it tighter / narrower across the neck?

 

I have some loaded rounds made by another, simpler die, and the external neck diameter on these are .246" & fit the rifle fine. Whereas, the external neck diameter on these new, unloaded cases, is .247" (using the .246" bush) I also have some empty, sized cases made by the "old" die & their external diameter is 0.245" and hold a bullet nice & snug.

Do you think it would it be best to go down just one size (0.244") to get it right as I think maybe a 0.242" bush would be too tight?

I'm certainly not new to reloading, but this is the first time using a sizer with separate bushes.

Thanks for looking & any advice given. Sorry if I've made this sound too complicated.

Cheers.

[trazman]

This video might help you.

 

[The Gun Pimp]

I've said it before - no point using a bushing-die if you aren't neck-turning.

 

If there are any discrepancies in the brass thickness in the neck area you will simply end up with different neck-tensions - probably exactly the opposite of what you were hoping to achieve.

 

Much better to remove the expander-ball and up-size with a mandrel.

 

If you do neck-turn your brass - unless you have a tight-neck chamber, you will simply increase the 'slop' in the neck area - again, counter-productive.

[Laurie]

223 brass has quite variable neck thickness depending on make. The norm for commercial brass is between 0.012" (12 thou') and 0.013", but can be more or less than either of these values. With 12 thou' neck thickness, the loaded round's neck should be 0.224" + 0.012" + 0.012" = 0.248". With 13 thou' necks, that rises to 0.250". A 0.246" bushing should therefore be fine for anything in that range, albeit risking getting a little too large for brass at the bottom end of the neck thickness range. So something is likely not right. Some makes of brass are below the 12 thou' level and a 246 bushing risks not sizing it enough but there has to be a large mismatch for the bullet to be so loose that it nearly falls into the case.

 

Measure the O/D of a fired case-neck. Remove the expander ball, resize a case and remeasure. The neck O/D should be reduced to around 0.247" with a 0.246" bushing allowing for a thou' of spring-back. See if that holds a bullet in your brass. If it's significantly larger than 0.247", there would likely be a problem with the bushing's actual as opposed to marked size. if the fired case measures 247 and still won't hold a bullet, the brass is too thin for that bushing and you either need to change the make of brass or get a smaller bushing.

 

If the above is OK, then replace the expander and try again to see if it over-expands. This is really rare though. (Better to use a mandrel expander as a separate step as TGP says anyway, but the factory expander shouldn't enlarge the neck so much that it can't grip a bullet.)

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Once again, very many thanks for all your inputs, your time spent replying is really appreciated.

All the best!