So Confused On Neck Sizing My 204 Round!

[bow shot]

Now about neck sizing... If you run your brass through the Lee collet sizer once, and the seat a bullet, does the bullet seat properly, or does it just fall into the case?

I ask this because you can actually size the bass properly, but not feel anything in the press handle, like a bump or sudden resistance as it happens (other than the primer getting popped out).

[GaCop]

The only time I've run into cases shortening is when I fire form 223 Rem to 223 AI.

[Rick in Oregon]

Case shortening: Happens almost every time when fireforming new wildcat brass to the new caliber from the original parent case. I just formed 500 20 Vartarg cases, and the lesson about NOT length trimming new cases until AFTER fireforming came home solidly.....almost every brand new case was a different length after fireforming. That's the time to trim, not before. Same goes for any factory new brass.....don't trim prior to firing, wait until they've been fired prior to trimming, or you'll be chasing your tail and be over-trimming your brass.

I do however, use my VLD tool to properly bevel the case mouth on new brass to seat a bullet without any jacket shaving, as new brass is horrible under magnification in the neck mouth area. Also a nice chamfer on the outside of the case neck prior to bullet seating.

Once all those 500 Vartarg new cases were trimmed, repeated firing shows they all are within .002" in length.

[futuretrades]

RIO Thanks for your reply and experience and knowledge. I will be going thru the same thing when my Var Targ gets here.

[GaCop]

Fire forming 223 Rem to 223AI always shortens a case from base to mouth but I've never experienced a shortening at the neck/shoulder junction because the case shoulder is expanded forward in the AI chamber.

[Rick in Oregon]

I've never experienced a shortening at the neck/shoulder junction because the case shoulder is expanded forward in the AI chamber.

Agreed.....who said anything about shortening from the neck/shoulder junction?

[stef]

My guess is... the difference is only .004 inches and the unfired case at the junction of the neck & shoulder may not be a real definite angle, or different angle and when the bolt (is it a bolt action?) is closed large forces are exerted on the case as it is shoved into the chamber -- like crush fit. Upon firing the case is fired formed with a definite angle between neck & shoulder or essentially the angle has been changed (delta dimension) and subsequent measurements show .004 inch less.

The Lee collet die situation -- how thick are the sides of the neck? and what is the diameter of the rod where the case is squashed by the collet? It should work. I am in the process of getting Lee to make me a set of collet dies for a 6.5-06 and they need a once fired case. Possibly you might tell them of your problem. The responded to my emails. I am a real fan of Lee dies and use them with other dies.

As far as full length vs neck sizing I like to use body dies with the Lee Collet dies. I like to easily chamber rounds but don't like to excessively squeeze down case necks then expand them back to size with an expander plug (work hardening) and many full length dies do just that except for those that use selected size bushings. I also turn necks as a way to adjust neck tension so the bullets will stay seated and the neck is a good fit with the chamber. Chambers for wildcats that need to be fire formed are normally cut short so the round to be fire formed has a "crush fit" inside the chamber.

I have yet to load a .204 Ruger round and I am tracking this stuff well.