7mm WSM Redding bushing size after neck turning

[VKC]

I was using a Forster FL resizing die for my non-neck turned Winchester 7mm WSM brass but then decided to try neck turning just to even out the necks to get more consistency. Before the first firing after neck turning, my Forster FL resizing die gave just enough tension to hold the bullet, but after one firing there isn't enough neck tension to hold the bullet solidly. I only neck turned minimally to even them out.

Now it is looking like I will have to use bushing type FL resizing dies to get more neck tension. I planning on getting a S-type Redding FL bushing resizing die.

Question: what size bushing should I use?

Thanks in advance for your help.

 

[gvanhyning]

Seat a bullet and measure neck diameter. Subtract .002" and that will be the bushing size for standard neck tension.


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[ZiaHunter]

If you have access to a tube micrometer, measure neck wall thickness multiply that value by 2 add the diameter of the bullet then subtract the desired tension. If you are going to turn necks make sure you turn all of them to the same thickness and don't expand the necks when sizing. You will find that you will eventually acquire several bushings for each caliber. I have a minimum of three and more for certain calibers since I don't turn all calibers.

 

[VKC]

Seat a bullet and measure neck diameter. Subtract .002" and that will be the bushing size for standard neck tension.


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If the neck tension is too little with seating the bullet, would the measurement be wrong?


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[knockemdown]

I turn the necks on my Winny 7WSM brass to ~.0145" to clean em up, and run a .310 Ti bushing for resizing...

 

[gvanhyning]

If the neck tension is too little with seating the bullet, would the measurement be wrong?


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You only need tension enough to hold the bullet securely. If the current sized case neck will not support or hold the bullet then you'll need to measure neck wall thickness as described by ZiaHunter.

 

[VKC]

So somewhere around 0.310 bushing for light neck turned, and 0.312 for non-neck turned sound about right?

 

[Jeffvn]

Its hard to say what bushing you need unless you know the thickness of the brass. Its best if you measure the brass with a tub micrometer. If you don't do that you can back out the number by measuring several of loaded rounds then subtracting .284. Once you clean it up it should be consistent; before that you might be surprised how inconsistent it is.

My neck-turned 7WSM when loaded is .310 (I use a .308 bushing), and goes into a .313 chamber.
My "cleaned" neck 7WSM when loaded is .312 - I use a .310 bushing.

The base brass is roughly 0.015 +/- (when I clean it to 0.014 it does not cut the entire neck of the brass.)

Jeffvn

 

[VKC]

Its hard to say what bushing you need unless you know the thickness of the brass. Its best if you measure the brass with a tub micrometer. If you don't do that you can back out the number by measuring several of loaded rounds then subtracting .284. Once you clean it up it should be consistent; before that you might be surprised how inconsistent it is.

My neck-turned 7WSM when loaded is .310 (I use a .308 bushing), and goes into a .313 chamber.
My "cleaned" neck 7WSM when loaded is .312 - I use a .310 bushing.

The base brass is roughly 0.015 +/- (when I clean it to 0.014 it does not cut the entire neck of the brass.)

Jeffvn

I used the 0.310" bushing on my cleaned neck turned cases and that worked great. Thanks Jeffvn