Lee (.308) Collet neck sizer questions

deepcore · June 25, 2011, 12:30 AM

Couple of probably stupid questions about the Lee Collet Neck Sizer (LCN):

1. Is the amount that the LCN sizes the case neck/mouth down to a fixed value? If you wanted snugger or looser are there options?

2. When checking to make sure I've sized correctly or want to work on setting my seating die (without powder or primer in the case), and after I've pulled the bullet out, is it okay to run these bullet pulled cases right back into the LCN? Or should I expand the mouth back up using my full length sizer (just enough for the expander ball to do this, loading for bolt gun so don't need the full length sizing at this point yet). Wanted to make sure using the LCN to expand the case mouth back up was okay.

steve4102 · June 25, 2011, 01:48 AM

#1. Yes, it is a fixed value. The neck is squeezed-formed around a mandrel. The diameter of the mandrel dictates neck tension. If you want "snugger" you reduce the size of the mandrel, either by purchasing a "reduced mandrel" from Lee ($5) or chuck the mandrel into a drill and polish it down to your desired size.

#2. Sure, run it back through the Collet die as many times as you wish, won't hurt a thing.

Ike666 · June 25, 2011, 09:01 AM

Not sure if this is enough of a difference to make a difference, but you may want to use annealed brass if you are going to experiment with multiple sizings.

While the whole case is not being worked, the neck is - and that tends to be a failure point. Each working hardens the brass just a little and over time can shorten the time until you start to get stress cracks after firing.

I think for what you are doing (experimenting with seating depths), this is not so much of a problem. But once you decide on an optimal seating depth, set that case aside and just use it for this type of experimentation.

I use the LCN for all of my fireformed brass and it works just great.

June 25, 2011, 09:01 AM	#3
Ike666 Senior Member Join Date: October 10, 2009 Location: SW VA Posts: 491	Not sure if this is enough of a difference to make a difference, but you may want to use annealed brass if you are going to experiment with multiple sizings. While the whole case is not being worked, the neck is - and that tends to be a failure point. Each working hardens the brass just a little and over time can shorten the time until you start to get stress cracks after firing. I think for what you are doing (experimenting with seating depths), this is not so much of a problem. But once you decide on an optimal seating depth, set that case aside and just use it for this type of experimentation. I use the LCN for all of my fireformed brass and it works just great. __________________ ___________________ "I'm your huckleberry."

June 25, 2011, 12:30 AM	#1
deepcore Senior Member Join Date: July 24, 2010 Posts: 364	Lee (.308) Collet neck sizer questions Couple of probably stupid questions about the Lee Collet Neck Sizer (LCN): 1. Is the amount that the LCN sizes the case neck/mouth down to a fixed value? If you wanted snugger or looser are there options? 2. When checking to make sure I've sized correctly or want to work on setting my seating die (without powder or primer in the case), and after I've pulled the bullet out, is it okay to run these bullet pulled cases right back into the LCN? Or should I expand the mouth back up using my full length sizer (just enough for the expander ball to do this, loading for bolt gun so don't need the full length sizing at this point yet). Wanted to make sure using the LCN to expand the case mouth back up was okay.

June 25, 2011, 01:48 AM	#2
steve4102 Senior Member Join Date: December 23, 2005 Location: Minnesota Posts: 2,955	#1. Yes, it is a fixed value. The neck is squeezed-formed around a mandrel. The diameter of the mandrel dictates neck tension. If you want "snugger" you reduce the size of the mandrel, either by purchasing a "reduced mandrel" from Lee ($5) or chuck the mandrel into a drill and polish it down to your desired size. #2. Sure, run it back through the Collet die as many times as you wish, won't hurt a thing.