My routine for concentricity and neck tension.

[EXPRESS]

I want to share my reloading routine which I developed with a .338 win mag that would not shoot as well as I wanted, with the bullets I wanted it to.
It's shooting just fine now, but I came across a new issue.
The two things I wanted to address are neck tension and concentricity.
Neck tension became an issue when I thought it was the reason why I wasn't able to get consistent seating depths and bullets being retained in the die. Turns out it was a die issue. Concentricity, well, because. I don't measure it, but we all want more of it.

I give my cases a wipe down with a rag, slip on a latex glove lube up with imperial die wax, then give them a spray with a silicone lubricant.
Run through a collet belted mag die, which is something I've never had to do in reloading over a dozen belted mags for 15 years. This rifle has a large chamber I suppose.
Then I run them through a FL die.
It should be done the other way around, but these cases will not run through the FL die unless you resize with the collet first.
Then I tumble in stainless media and dry.
After that they get run through the FL die again, bug this time with no expander plug.
Prime, charge.
I seat in two increments, by running each case through the die on a "zero" setting then a second time at the final depth. Second time is bump of 1mm (0.04") and I turn the cases and give them a second gentle bump at the same setting.

Now, what I don't like is that I noticed that some cases shave copper off the bullets and some don't. The bullets are CNC turned and there is no inconsistency in diameter, so it must be the case necks.
Is it due to the tumbling and drying or the second pass with no expanded that does this?
The accuracy is good, but I have to check now that the cartridges that shaved shoot the same as the ones that don't shave.

Anyone else have this happen?

 

[Rich Coyle]

I used to get the shaved bullets. Now I champher the inside of the neck mouth.

 

[Garycrow]

I'd agree that you need to chamfer the necks better. Get a good chamfer tool.

L.E. Wilson Chamfer Deburring Tool 17 to 45 Cal

 

[EXPRESS]

I do need to chamfer, and I alread have the Redding VLD and the Wilson tool.

This was once fired Norma custom brass, so as yet I hadn't trimmed it and it was pretty good around the case mouths.

Next firing I will give it a trim and chamfer. When I chamfer, I put the tool in a mini lathe on a slow setting, time it for 3 revolutions, and go through. Then I put a cup shaped tool in the lathe which is filled with 1000grit steel wool and use that to polish. Give a very nice result.

I also lube the bullets with imperial wax, initially because I was trying to stop them from sticking inside the die, but I found that it makes seating that bit smoother too.

 

[Garycrow]

I wouldn't lube the bullets with imperial, you might glue them in if the ammo sits for a while which would defeat your attempt for consistent neck tension. I wouldn't lube them with anything. I like to brush my necks with a nylon brush to remove residue.

 

[EXPRESS]

Noted.

 

[tbrice23]

Express, if you are FL sizing with out the expander plug ,the necks are too small inside diameter. Thats why you are shaving bullets. ?????
You need a bushing FL die.

 

[tbrice23]

Or see of Lee makes a Collet neck die for 338wm.
The absolute straightest ammo I make is sized with a Redding body die and then lee collet neck die, because nothing is dragged up through the neck. I measure the run out of every round I make.

 

[EXPRESS]

First I FL size with the expander plug and decapper in the die, then I run them through the same die minue the expander and stem, so that the necks are tighter and I have better concentricity because as someone posted earlier, no plug is being dragged through the neck. However the Forster dies have a plug that onlye goes to the base of the neck, and once polished, it doesn't reallt seem to drag or hang up like the RCBS ones.
I don't suppose it would be a bad idea to eliminate that step from the process. I just fell like more neck tension is a good thing.

 

[tbrice23]

Too much neck tension actually causes crooked ammo, and shaved bullets. .002" neck tension is ideal.

 

[Garycrow]

...

 

[EXPRESS]

I checked my neck tension, and by running the case through the die with no expander, I am around .009" neck tension. I don't have a mic so that measurement could be slightly off.

This is because I shoot the CEB bullets which are 0.0078 undersize.
With a Matchking, Id be at .016" if I size using the expander, as you usually would,

The rifle shoot much better this way, I'll see what happens in a side my side trial.

 

[918v]

.009" neck tension is excessive.

.001" to .002" is ideal.

Redding body die and a Lee collet neck die is the easiest recipe for concentricity.

 

[tbrice23]

Or see of Lee makes a Collet neck die for 338wm.
The absolute straightest ammo I make is sized with a Redding body die and then lee collet neck die, because nothing is dragged up through the neck. I measure the run out of every round I make.

Ok.