Neck turning logic

[Sharpshooter_308]

I have a Foster neck turner on order. See if my logic is correct. I am reloading for 308 win and use a Lee collet die. Since the die uses a fixed mandral to "smush" the brass around, then all problem areas will be pushed to the outside. Therefor, I dont really need a special die to do this.

Am I correct?

Thanks

[Elkbane]

You probably need to explain the your logic a little better with regard to the relationship between the neck turner and the Lee collet die. If you're asking whether the mandrel in the collet die can substitute for an expander mandrel before turning, then the answer is no.

Two reasons - the collet die will not establish a clean neck/shoulder junction fo you to set your neck turner against, and the collet itself will leave some shallow ridges on the outside of the case, which will get turned off. This will result in thinner "streaks" running parralel to the neck along the length of the neck. Also, the collet may not reach all the way to the shoulder, so when you turn the whole neck to a consistent OD, the lower protion will be thinner than the upper portion.

The preferred method is to F/L size with the expander ball out of the die, then run the case over an expander to bring the ID up to a tight fit on the turner mandrel while turning.

Elkbane

[wbm]

The preferred method is to F/L size with the expander ball out of the die, then run the case over an expander to bring the ID up to a tight fit on the turner mandrel while turning.

+1. I use the Lee's and the Foster and this is the way to go. Might want to consider a bit of dry lubricant on the Lee turner mandrel they can get a bit stiff to turn when the fit is tight.

[Kawabuggy]

I've done it the way the OP states-I've used a LEE collet die to size the neck, and then ran them over my K&M neck turner. Here is why I don't see a problem doing it this way; The mandrel on the K&M neck turner will act as an expanding mandrel. My experience has been that the neck I/D of the case will be smaller than the O/D of the mandrel, and the neck will have to be forcible pushed onto the mandrel expanding it as it goes. For this reason, you WILL have to lubricate the I/D of the case neck and/or the mandrel on the cutter to keep the brass from seizing on the mandrel.


After doing this I've then used a Redding Case Gauge to check that the neck was the same thickness all the way around. Yep.
http://www.redding-reloading.com/index.php?option=com_content&view=article&id=46:case-neck-gauge

Note that this will not address the issue with the neck/shoulder junction that was mentioned above. The way around that is simple, when you neck size a piece of brass in the future with a turned neck, put a thin washer around the case body so that as you push it up into the LEE collet die, the area of the case neck closest to the shoulder will not be sized, and you are left with a raised "hump" just in front of the neck/shoulder junction. This hump will help to center the round in the chamber, and will also insure you don't have any doughnuts forming inside the case. Thank you Reloadersnest.com