turning necks twice?

[TackDriv3r]

When my 6.5 x 284 with .286" tight neck was built 11 years ago, my gunsmith turned 200 pieces of Lapua brass back then. Yesterday I used a batch of 20 old pieces of brass and neck sized them. I noticed some seated more than snug than the others. I measured the neck thickness of some pieces of brass and it shows .001" thinner than others. Is it normal that after some firings that necks are inconsistent? There may be a donut inside the neck but I don't believe I am seating the bullet deep enough to touch the donut, if there is one.

So I full sized 20 more pieces and ran them through a mandrel and K&M neck turned very slightly, and some necks cleaned up more than others.

Also the curved area where the neck / shoulder junction meets, I had seen the cutter cutting more material from there, but slightly cutting into the shoulder.

Is this a red flag and possible neck / shoulder separation since its been neck turned twice?

This is just an experiment I am doing, since 100 pieces of new Lapua brass is coming soon and all will be turned to .003" less than chamber neck diameter

Just wondering if turning necks twice is a no no?

 

[Uncle Ed]

Full length resizing, meaning reducing and squeezing the case diameter causes upward brass flow in the die. Meaning brass flow into the case neck, but I do not know if firing a neck sized only case if there is also upward brass flow.

I have neck turned a few older full length resized cases a second time and removed brass just above the shoulder neck junction. And I assume how often you need to trim your cases is a indication of brass flow into the neck. Meaning you originally neck turned the case neck to remove the high or thicker sections of the neck. So brass flow into the neck would also be uneven and what you found the second time you turned your necks.

As a after thought in a post here it was mentioned that only sizing 1/2 to 3/4 of the neck helped center the case in the neck of the chamber. But if brass flow into the neck is not even around the circumference of the neck this method could cause misalignment of the bullet with the bore.

 

[TackDriv3r]

Let me ask this question.

How much brass "thinning" may occur at the neck / shoulder junction if repeated cutting is needed to remove the dreaded donut?

Here is a pic of my turned necks a 2nd time after the gunsmith did the first time 11 years ago to .283 neck for a .286 neck chamber. ( assumed sized of .283 ) Does it look fine? It's my first time turning necks.

All three are full sized.

Top is unturned.

Bottom pic is turned and cut more fully into the shoulder.

Middle pic is turned and slightly backed off from the shoulder.

Which of the last two pics looks more appropriate?

 

[Uncle Ed]

I was impressed with the photo below posted by another reloader and how the cutter angle matches the shoulder angle.

I just have a older Hornady neck turning tool and my cutter does not match my shoulder angle.

Does this better streamlined shoulder angle from the cutter help with where to stop. Meaning less chance of turning down too far and screwing up the brass.

 

[TackDriv3r]

I would go with number 2. You want to go as close to the shoulder as possible without digging in.

To do it right you need to push the excess brass that is in the neck to the outside with a mandrel where you can shave it with the turner.

Yes Sir, I did full size first, then run a K&M mandrel with lubed inside neck and turned the necks after.

 

[CaptainMal]

On both of my BRA's I find that about every other firing I will take off brass from the turned neck just above the neck. Bet I could do it every time as it just seems to thicken there after each firing.

 

[Don Shelton]

On both of my BRA's I find that about every other firing I will take off brass from the turned neck just above the neck. Bet I could do it every time as it just seems to thicken there after each firing.

Above the shoulder?

 

[6BRA]

making sure your inside neck diameter matches your turning mandrel exactly, and anything less than zero runout on control of the linear action can distort the neck fit to the mandrel. If you dont have zero runout, and a tight neck to mandrel, you can neck turn brass, rinse and repeat and see shavings. JMO.

 

[Lone Hunter]

Above the shoulder?

Don, Just an FYI. Thread is 4 yrs old so hopefully you will get a response. Run a search and there are many neck turning threads. Look down below and there’s some threads there. Says “Similar Threads”. Hopefully it will help you.