Home Forums Reloading Big Game Rifles School me on the use of a neck sizer die

With the Lee Collet Neck Sizer, neck turning is less critical, IMO. There is no expander to pull a slightly asymmetrical neck crooked, the mandrel keeps is aligned.

Concentric ammo isn't that hard to achieve with this die, in fact this is about the slickest way to produce very good ammo with min. case prep.

But, I'm not a bench rest shooter...

DF

I have other rifles that are about as accurate without all that fuss. The Lee Collet neck sizer is a "cheap trick" for producing good, concentric ammo...

Why make it hard...

Easy is mo betta...

DF

Some of their stuff is marginal, some really good. The collet neck sizer and factory crimp die are their best offerings, IMO.

DF

I called Lee to ask about ordering a .223 body die, for bumping shoulders, and the customer service lady couldn't understand what I wanted.
She transferred me to one of the technical guys who understood what I wanted and proceeded to tell me the astronomically high set up fee (around $150 IIRC) to make me one.
I asked why they couldn't just ream out the neck of an existing full length die. He said they couldn't because it's hardened steel.
So, being the DIY type, I simply ordered a standard F/L die and drilled out the neck. Works great and much cheaper than a Redding body die.

I called Lee to ask about ordering a .223 body die, for bumping shoulders, and the customer service lady couldn't understand what I wanted.
She transferred me to one of the technical guys who understood what I wanted and proceeded to tell me the astronomically high set up fee (around $150 IIRC) to make me one.
I asked why they couldn't just ream out the neck of an existing full length die. He said they couldn't because it's hardened steel.
So, being the DIY type, I simply ordered a standard F/L die and drilled out the neck. Works great and much cheaper than a Redding body die.

The instruction say to screw in until it contacts the shell holder THEN 1 FULL ADDITIONAL TURN. This is garbage. You do this and you can collapse shoulders as a number of folks here have attested to. 2/3 to 3/4 of a turn will be your sweet spot.

Another thing to be aware of is neck thickness. Case brands vary in this regard and can vary within the same manufacturer by different lots.

The first thing I recommend is to ignore the instructions supplied with the die.

The second thing I recommend is to ignore whether or not the press you're using cams over at the top of its stroke.

The die squeezes the neck onto a mandrel, so for a given neck thickness there is a finite limit to how much sizing you can achieve. This die will need adjustment to suit different thicknesses of brass.

Raise the press ram to the top of its stroke. Thread the die into the press until the bottom of the sizing collet (not the die body) just touches the shell holder. Measure the neck OD of a piece of brass.

Run the brass through the die using a full press stroke. It should take no effort since if you're set up as described the die has done no sizing. Turn the die into the press about 1/4 turn. Run the brass in again. You probably won't feel much sizing going on, but give the neck a measurement just to see. If it's still nothing, screw the die in another 1/4th and try again. You'll may start feeling a bit going on as you work the press handle, and if so you'll be able to measure a little sizing taking place.

Rinse and repeat using 1/16th turn in increments for the die. You'll feel increases in the force required for the sizing stroke. Since you're measuring the neck after each pass you'll eventually find two increments where the neck didn't get any smaller. NOW STOP TURNING THE DIE INTO THE PRESS. Remember you're squeezing the brass against a solid steel mandrel which isn't going to give, so even if the press stroke didn't feel like it took very much force the neck is as small as it's going to get.

There's a learning curve to the die, but it isn't hard.

I like to run cases through the die twice, spinning the case about 1/3 turn (rather than the 1/2 turn in the instructions) between passes. This means the parts of the neck that were under the splits in the collet fingers on the first pass will get hit on the second.

Correctly executing the set up method I outlined above makes camming over or not a moot point, and it will not even come close to popping the cap. Furthermore since the full press stroke is used every time I don't have to "judge my lean" on the handle.