Bushings with an expander. What’s my neck tension?

[DellaDog]

Currently, I load 223 with Lapua and RWS brass and use two different bushings, 246 and 248. I chose these sizes based on Redding’s instructions which say to measure the neck size with a loaded round and subtract .001.

After purchasing a Dillon 550 I started expanding with a carbide turning expander as the first stage. The question I have is, other than not overworking the brass is there any reason I shouldn’t just use a single bushing for both brass types since I’m running them all through the same expander?

Is my “neck tension” really just .001 since I’m using the expander?

Thanks.

 

[giumau1]

I am not enough knowledgeable to question your reloading process, however here is a cheap answer to your final question:
Ballistic tools

 

[kyzim311]

Load 10 shots of the thicker brass with each bushing and see which shoots better. I personally have had better luck running 0.002" neck tension, but it will depend on what your gun likes.

 

[DellaDog]

The question really amounts to - if you're using an expander to open the all necks up the same, why use a different sized bushing to begin with?

 

[kyzim311]

Two reasons, the first you already hit on which is overworking the brass. The other would be concentricity as working the brass more than needed can cause concentricity issues. It is going to be hard for anyone to say for certain if there will be any impact on your group sizes or not, which is why I recommended a quick test.

 

[DellaDog]

Thank you. Seems to be addressed here as well.

 

[jakelly]

Your different bushing sizes are due to different thicknesses of brass. Expander size is irrelevant. Expander and bushings are two different methods to accomplish the same things. Not really sure why you are using both.

 

[DellaDog]

Not really sure why you are using both.

Because I need something to do with the first stage
Actually, it's a feel good thing that seems to even out the seating pressure. (Since imperfections are pushed inside the neck?)

 

[jakelly]

Yes, the reason you use two different bushings is to get the same neck tension. If you use a single bushing for both brass types, you’ll get different neck tensions.

If you want to use one bushing, you need to turn the necks on the thicker brass down to match the thinner.

 

[jakelly]

Ok, I get what you’re saying. Yeah, you could use one bushing.

 

[Baron23]

Expander and bushings are two different methods to accomplish the same things. Not really sure why you are using both.

Perhaps you will help someone just getting to reloading metallic.

My very vague and totally uninformed understanding is that the expander mandrel opens the neck to some set size and replaces expander balls on a FL sizing die, for example. While the bushing type die provide the compression for neck tension and that bushings versus fixed neck OD in a standard FL/neck die, allow you to take into account different thickness of the brass at the neck.

I must be confused....could you explain as it would appear that use of a mandrel for expansion would absolutely require either a bushing or standard FL/neck die to compress it back to have neck tension.

Thanks in advance for your time to consider my inquiry.

 

[kyzim311]

Perhaps you will help someone just getting to reloading metallic.

My very vague and totally uninformed understanding is that the expander mandrel opens the neck to some set size and replaces expander balls on a FL sizing die, for example. While the bushing type die provide the compression for neck tension and that bushings versus fixed neck OD in a standard FL/neck die, allow you to take into account different thickness of the brass at the neck.

I must be confused....could you explain as it would appear that use of a mandrel for expansion would absolutely require either a bushing or standard FL/neck die to compress it back to have neck tension.

Thanks in advance for your time to consider my inquiry.

You definitely need some form of die to squeeze the neck back down to use a mandrel to set neck tension. What you are missing is you can skip an expander ball or mandrel step with bushing dies as you can set neck tension by selecting the size of your bushing. It is redundant to pick your neck tension twice in the reloading process.

 

[Baron23]

You definitely need some form of die to squeeze the neck back down to use a mandrel to set neck tension. What you are missing is you can skip an expander ball or mandrel step with bushing dies as you can set neck tension by selecting the size of your bushing. It is redundant to pick your neck tension twice in the reloading process.

Ah, I think I may have misunderstood. I rather thought you use the expander mandrel and THEN using the bushing to tighten the neck up again.

If I understand you correctly, you are saying this is redundant because you use some die or another to compress the necks and THEN use the mandrel to open them to the diameter you want.

Or am I misunderstanding yet again.

 

[kyzim311]

Ah, I think I may have misunderstood. I rather thought you use the expander mandrel and THEN using the bushing to tighten the neck up again.

If I understand you correctly, you are saying this is redundant because you use some die or another to compress the necks and THEN use the mandrel to open them to the diameter you want.

Or am I misunderstanding yet again.

I think you are getting it. If using a mandrel, it comes after the sizing die. Most are 0.001-0.002" smaller than bullet diameter to make sure you have enough grip/ neck tension on the bullet.

 

[2aBaC̶a̶]

Spring back may vary.
Bushings control neck OD
Mandrels control neck ID
Which do you care about more?

 

[DellaDog]

Mandrels control neck OD

ID?

 

[2aBaC̶a̶]

ID?

Yes, fixed. Lol

 

[jakelly]

Ah, I think I may have misunderstood. I rather thought you use the expander mandrel and THEN using the bushing to tighten the neck up again.

If I understand you correctly, you are saying this is redundant because you use some die or another to compress the necks and THEN use the mandrel to open them to the diameter you want.

Or am I misunderstanding yet again.

Yeah, you’re tracking. On a fired case the mouth is already larger than a bullet so an expander isn’t any help. The neck is larger in OD by whatever the chamber reamer allows. ID therefore follows.

In a traditional FL sizing die the case passes around the expander ball, gets sized down at the top of the stroke, and drug over the expander on the down stroke. In a bushing die the neck is sized exactly at the top of the stroke, the operator picks the size that yields the neck tension he wants. There are expander balls with the bushing dies, but I don’t know many that use them.

 

[Baron23]

You guys have all been great, thanks so very much