Neck turning, sizing die, and neck tension?

[MOOSE39465]

Like everyone else I'm trying to achieve the best possible accuracy I can. So I have been researching neck turning, sizing die, and neck tension. I have a few questions I would like to ask
1. What is the best Bushing type sizing die to obtain the proper neck tension after I neck turn?
2. What is the minimum case neck thickness? Including for semi automatic rifles.

The rifles I will be neck turning for is 243 win, 270 win, 6.5 Creedmoor, and 7mm Remington Magnum.

 

[MudMarine]

I will try and answer the best I know. I am open to corrections.

1. Choose a bushing that will size your necks .002 smaller than your projectile to get good consistent neck tension.

2. Most quality brass will clean up between 0.010 and 0.014. Edit: By cleanup, I mean that your thinnest brass in a lot can be found between 10 and 14 thousandths.

Obviously, the bushing you need is dependent on where your brass cleans up at.

Another way to go is to use a full length sizer and then use an expander die with a mandrel 0.002 smaller than your projectile. With this approach, the final neck thickness isn't critical (unless your chamber is special).

 

[dok7mm]

You'll have to measure the neck thickness of all the brass you're using in each rifle and know what your chamber neck diameter is, to get any idea of how much to turn for proper clearance.

The Redding neck bushing dies are top notch.

If your chamber necks are not custom tight necks or minimal, turning may not be the optimal route to pursue for much improvement in accuracy.

If you're shooting no-turn necks or factory sammi necks, FL dies and expander mandrels will be easier, cheaper and give excellent accuracy, if your rifles are capable. I have to turn necks for most of my custom chambers and I use expander dies instead of my bushing dies.

 

[MOOSE39465]

You'll have to measure the neck thickness of all the brass you're using in each rifle and know what your chamber neck diameter is, to get any idea of how much to turn for proper clearance.

The Redding neck bushing dies are top notch.

If your chamber necks are not custom tight necks or minimal, turning may not be the optimal route to pursue for much improvement in accuracy.

If you're shooting no-turn necks or factory sammi necks, FL dies and expander mandrels will be easier, cheaper and give excellent accuracy, if your rifles are capable. I have to turn necks for most of my custom chambers and I use expander dies instead of my bushing dies.

I have noticed a great deal of once fired brass has run out as bad as 3 thousands. I was hoping to make it more concentric in hopes of improving accuracy, but if you think I will not achieve that then it's not worth spending time and money on. Thanks for the info.

 

[MOOSE39465]

I will try and answer the best I know. I am open to corrections.

1. Choose a bushing that will size your necks .002 smaller than your projectile to get good consistent neck tension.

2. Most quality brass will clean up between 0.010 and 0.014. Edit: By cleanup, I mean that your thinnest brass in a lot can be found between 10 and 14 thousandths.

Obviously, the bushing you need is dependent on where your brass cleans up at.

Another way to go is to use a full length sizer and then use an expander die with a mandrel 0.002 smaller than your projectile. With this approach, the final neck thickness isn't critical (unless your chamber is special).

I have been researching a bunch and from what I gathered I could fl size my brass then neck turn. After that seat a bullet into the case. Take a micrometer a measure outside diameter of the neck then subtract 2 thousandths. That would give me a bushing size. Is that correct?

 

[MudMarine]

I have been researching a bunch and from what I gathered I could fl size my brass then neck turn. After that seat a bullet into the case. Take a micrometer a measure outside diameter of the neck then subtract 2 thousandths. That would give me a bushing size. Is that correct?

So you are proposing to full length size, turn the necks, seat a bullet and then subtract 2 thou so you can use a bushing sizer?

Seems convoluted way to get where you want to go. Why not just use a mandrel to expand the necks to 2 thou less than bullet diameter? Saves on bushing selection and second sizing.

 

[dok7mm]

If your brass has that much run-out after firing (not resized), it is more indicative of poor barrel/chamber alignment, a different problem.

 

[MOOSE39465]

So you are proposing to full length size, turn the necks, seat a bullet and then subtract 2 thou so you can use a bushing sizer?

Seems convoluted way to get where you want to go. Why not just use a mandrel to expand the necks to 2 thou less than bullet diameter? Saves on bushing selection and second sizing.

I understand what you are saying now. Thanks for the input.

 

[MOOSE39465]

If your brass has that much run-out after firing (not resized), it is more indicative of poor barrel/chamber alignment, a different problem.

I mostly purchase once fired brass. The measurements I take are before the brass enters my rifle. Usually if the case has considerable runout I separate it to the do not use pile. That pile has grown big and I hate to throw away brass. Even though it's only 15 dollars a 100. Lol

 

[dok7mm]

One of the keys to accuracy is a concentric inside diameter of the case neck. A mandrel pushes the variance to the outside of the neck, and leaves a concentric ID. You will have to have various sized mandrels to find your best tension for accuracy. Usually 1,2,& 3 thou under caliber.

 

[MOOSE39465]

One of the keys to accuracy is a concentric inside diameter of the case neck. A mandrel pushes the variance to the outside of the neck, and leaves a concentric ID. You will have to have various sized mandrels to find your best tension for accuracy. Usually 1,2,& 3 thou under caliber.

Good info thanks.

 

[bigngreen]

I mostly purchase once fired brass. The measurements I take are before the brass enters my rifle. Usually if the case has considerable runout I separate it to the do not use pile. That pile has grown big and I hate to throw away brass. Even though it's only 15 dollars a 100. Lol

I would not waste the time to make perfect brass fired from another chamber, it's kinda defeating the purpose, quality brass fired in your chamber with a FL bushing die will get you the largest step of improvement.

 

[Mikecr]

It'll take a bunch of work to get used brass right like ours is.
Possible of course, but less practical.

First thing for you to do is learn about sizing and measurement in general. Pick up a good book like; http://www.zediker.com/books/handloading/hlmain.html
Second is to think for yourself with everything you can learn along the way.

 

[DR 3006]

how do you decide between the choice of a bushing die or a mandrel? currently I have a basic 3 die set from Redding. 280 AI. I am wanting to get a more consistent setup.