Neck turning: the correct procedure?

[Campbell]

Merry Christmas to you all!

I am taking my 2 year reloading experience further. Please will you help me?

I have taken delivery of 200+ Lapua .308 cases.

30 odd of them are virgin cases, and the rest are once fired.

I have purchased the K+M neck turning lathe kit.

With the virgin cases, I have to use the K+M "expand mandrel" in order for the case to fit the K+M "tool steel pilot". When I do this, the case is a snug fit on the pilot.

However, the once fired cases (without any re-sizing) are not as snug on the pilot. So, do I re-size (Redding f/l with bushing) then use the K+M expander for neck lathing, AND then re-size again using the Redding ready for bullet seating?

Many thanks in advance.

Cam

 

[6mmcldasher]

simple answer is yes . use a brush on the inside of the neck before expanding the once fired stuff.

 

[Campbell]

simple answer is yes . use a brush on the inside of the neck before expanding the once fired stuff.

Many sincere thanks for your reply.

All of the cases will be s/ tumbled before any re-sizing procedure.

Cam

 

[rardoin]

Campbell,

First step is to resize the fired cases and new cases, then trim all to the same length. The reason for sizing all cases (the virgin cases, in theory, should not size when you run them through the die but sometimes the die will squeeze a few cases down a bit) is to get the neck shoulder junction at the same location from the base before trimming the case over all length. This should put the length of each neck the same. The turning tool 'length of cut' is set based on the length of the neck. If the necks are different in length, some cases may be cut too far into the shoulder and some cut a bit short of the shoulder...so the necks should be trimmed to the same length. Once trimmed, then runn all cases over the expander mandrel; lubricate the case mouth to prevent galling of brass onto the mandrel. Then turn your necks.

I hope this helps

 

[dkhunt14]

It is best to have a regular full length sizing die to size the neck all the way to the junction. Make sure enough take the expander out. The bushing die will not do this. Then expand them. Like said make sure you clean the inside of the necks. Matt

 

[skiutah02]

It is best to have a regular full length sizing die to size the neck all the way to the junction. Make sure enough take the expander out. The bushing die will not do this. Then expand them. Like said make sure you clean the inside of the necks. Matt

This^^^

It is important to size the neck all of the way to the neck shoulder junction. If, lets say using my brass as an example, the once fired case neck was 0.341 and the type s bushing FL sizer sized 90% of the neck to 0.336 and the expander opened it up to 337 to fit snugly on the pilot, you can see that the lower 10% on the neck will have 0.002 more metal removed than the rest of the neck (half the difference for each side). In my mind this not only gives nonuniformity to the neck you are trying to make uniform, it unduly weakens the brass at the n/s junction. While the numbers will vary for everyone, the effect will be the same unless you size ALL of the neck smalller than the expanding mandrel. Not a nt guru, but stuff I thought about before I started.

Drew

 

[spclark]

What others have suggested is good info. All I can add is use lube too, both on the mandrel and at the cutting edge as you turn & advance the crank.

My preference is for off-the-shelf thread cutting oil, while I'm positive there are secret formulas out there garunteed to make all your turned case shots go in the same hole.

 

[ab_bentley]

Do you have a tight neck chamber? Turning necks on a no turn or factory chamber will only degrade the brass faster.

Adam

 

[ShootDots]

A little trick here, especially with your virgin brass. When you run them into the mandrel, back the press handle off, lowering the ram, turn the case 1/3 turn in the shellholder and re-run it back in the mandrel die. Do this 3 or 4 times, it only take 2 seconds more, and you will feel the case start to enter the mandrel very smoothly. Now you know all the imperfections are pushed to the outside of the case wall and you can turn them off.

 

[mikecr]

I wouldn't turn anything but expanded new brass (no need to).
No firing, or FL sizing. Once doing these(either) the brass has reformed and you missed the chance to mitigate donuts.

 

[ShootDots]

I wouldn't turn anything but expanded new brass (no need to).
No firing, or FL sizing. Once doing these(either) the brass has reformed and you missed the chance to mitigate donuts.

^^^^^Personally, I agree with this statement 100 percent. I have done it after firing and although it "worked" it is not the best way to accomplish this task correctly.

 

[Campbell]

Many thanks to you all.

My original question omitted the steps that I have done before purchasing the K+M neck turning lathe, but after a bit of Festive practice case prep, here is my revised non-neck turned pre-powder charge procedure, which I would be very grateful for your critique: -

1) Cases are cleaned by s/s tumbling (assuming that the primers have been removed) If old primers are present, I use a Lee Universal De-capping die before cleaning.
2) Cases are dried
3) Cases are f/l resized.
4) Cases are trimmed
5) Cases are de-burred
6) Primer pockets are unified
7) Flash holes are unified
8) Cases are then put through the K+M expander die.
9) Cases are neck turned (once only, obviously).
10) Cases are then f/l resized again
11) Cases are re-tumbled for a short time to remove any swarf/lubricant.
12) Cases are dried
13) Cases are primed

In steps 3-4 I use the Lee Resizing Lubricant as I have found it be good stuff.

Edited after taking the advice of dedogs & rardoin

 

[Cool Tool]

Many thanks to you all.

My original question omitted the steps that I have done before purchasing the K+M neck turning lathe, but after a bit of Festive practice case prep, here is my revised non-neck turned pre-powder charge procedure, which I would be very grateful for your critique: -

1) Cases are cleaned by s/s tumbling (assuming that the primers have been removed) If old primers are present, I use a Lee Universal De-capping die before cleaning.
2) Cases are dried
3) Cases are f/l resized.
4) Cases are then put through the K+M expander die.
5) Cases are neck turned (once only, obviously).
6) Cases are then f/l resized again
7) Cases are trimmed
8) Cases are de-burred
9) Primer pockets are unified
10) Flash holes are unified
11) Cases are re-tumbled for a short time to remove any swarf/lubricant.
12) Cases are dried
13) Cases are primed

In steps 3-7 I use the Lee Resizing Lubricant as I have found it be good stuff.

My question why are you turning to begin with

 

[Campbell]

My question why are you turning to begin with

Hi George

In order to obtain a better chance of consistent neck-tension and concentricity.

 

[Cool Tool]

Hi George

In order to obtain a better chance of consistent neck-tension and concentricity.

Well if you have a standard chamber take as little as possible so you don't have to much clearance with a loaded round good luck.

 

[Campbell]

Well if you have a standard chamber take as little as possible so you don't have to much clearance with a loaded round good luck.

Hi George

The amount I take off is very small. The K+M allows .0002 increments.

The advice that has been given to me is that one should effect at least 80% of the neck surface in order to improve consistency.

 

[Cool Tool]

Hi George

The amount I take off is very small. The K+M allows .0002 increments.

The advice that has been given to me is that one should effect at least 80% of the neck surface in order to improve consistency.

Good luck you definitely have some of the best tools.

 

[Campbell]

Good luck you definitely have some of the best tools.

Many thanks . I just wish I had a commensurate amount of knowledge!

 

[dedogs]

here is my revised non-neck turned pre-powder charge procedure

Steps 7 & 8 should be done before step 4. It is absolutely essential that all the case necks be the same length for accurate turning (as was stated by rardoin above). If you want to check length again after turning and full length re- sizing the second time that's O.K. but may not be necessary. dedogs

 

[dannyjbiggs]

Merry Christmas to you all!

I am taking my 2 year reloading experience further. Please will you help me?

I have taken delivery of 200+ Lapua .308 cases.

30 odd of them are virgin cases, and the rest are once fired.

I have purchased the K+M neck turning lathe kit.

With the virgin cases, I have to use the K+M "expand mandrel" in order for the case to fit the K+M "tool steel pilot". When I do this, the case is a snug fit on the pilot.

However, the once fired cases (without any re-sizing) are not as snug on the pilot. So, do I re-size (Redding f/l with bushing) then use the K+M expander for neck lathing, AND then re-size again using the Redding ready for bullet seating?

Many thanks in advance.

Cam

Personally, I would go ahead and once-fire the 30 remaining cases out of the 200 total, clean them well, FLR all 200, trim to common length, use expander mandrel, and neck turn all 200 from a common size. (You will probably realize a little looser fit on the pilot mandrel after using the expander mandrel by working with all once-fired brass.) I would then match my cutter neck-shoulder angle to that of the cases shoulder, and neck turn up into the shoulder a bit to help mitigate doughnuts forming. Sinclair makes an excellent neck turning lubricant.

Dan