New one on me - neck sizing with F/L die

[elkeater2]

When we first got my wife's .243 I was reading all the stuff and trying things out. Forty years ago. People talked about neck sizing fired brass with full length sizing dies, just by backing off the die a little in the press. Better accuracy, longer brass life - what's not to like? I loaded some up for her using Hornady 100 gr. spire points. Funny thing is, I recently found all the .243 loads I ever made, some of them pretty old. Some of those, loaded with the 100 gr. Hornadys, I cannot close the bolt on now!!! Two or three it will close, but with major effort. Good grief, I'm glad I didn't load Mom up with those recently when the buck of the century was in her sights. :shock: The only thing I can figure is brass was sort of sprung down by the "neck sizing" process. Like the base of the neck right down to the rim and base of the case was not supported or in contact with the die walls when the neck was getting squeezed and expanded. So down pressure on the main case body sort of sprung it down a little, and over a lot of years it recovered. That's my theory anyway. I'm just curious if anyone had experienced this. Kind of curious but not curious enough to search the whole web - what are arguments against neck sizing with a FL die? I think I just found one :grin:
EE2

 

[steve4102]

Trying to neck size with an FL die only "works" if the case has a goodly amount of taper.

The 243 is a relativity straight case, thus simply backing the FL die out a touch will still allow the die to contact the case body.

Once the die makes contact with the case body, you are no longer Neck sizing.

Making contact with the case body without making contact with the Shoulder will usually push the shoulder forward and cause difficulty in chambering.

 

[rick smith]

You cannot neck size with a FL die without having an effect on the remainder of the case. Just take a fired case an insert it into a FL die by hand. The body touches before the neck is even close to the neck sizing area. That is probably the reason your old cases will not fit. As the case is being sized the case gets longer and stays that way unless you force the shoulder down by bumping the shoulder back with the die. You can set the FL die to partially FL the case to fit your chamber. If you want to neck size, get a bushing neck die or a standard neck die.Rick.

 

[elkeater2]

Good info Steve and Rick, and it makes sense. Still wondering why these cases that chambered a long time ago won't chamber now. Could be a faulty memory issue - but am wondering if it is even possible to do weird stresses to the case that will somehow cause them to change after loading. I don't have that many of them and am not conducting a bulk salvage operation or anything. Pretty sure I checked chambering back then like I do now. I know all about bushing dies, collet dies, neck size only dies now, but didn't back then.
EE2

 

[bigedp51]

When you full length resize the case is squeezed and the case can only move upward in the die and actually become longer. Meaning the case becomes longer than the chamber and the bolt is difficult to close or it will not close at all.

Below partial full length resizing can squeeze the case shoulder forward, blue dotted line.
Bumping means just pushing the shoulder .001 to .002 below or past the red dotted line.
Complete full length resizing with the die making hard contact with the shell holder is the green dotted line. This also can over resize the case for "your" rifle so bumping the shoulder back the minimum amount of .001 to.002 means a custom fit for your chamber.

You can use a full length die to neck size only but you only size 1/2 to 3/4 of the neck. BUT you must make sure your not moving the shoulder forward when doing this. To be truthful your better off full length resizing with minimum shoulder bump or setback than neck sizing the case.

Read below carefully, it was written by Kevin Thomas of Team Lapua USA and a world class competitive shooter

"The cartridge case should fit the chamber like a rat turd in a violin case"

Meaning a full length resized case is supported by the bolt face at the rear of the cartridge and by the bullet in the throat of the chamber. And the body of the case has no steering or aligning effect on the bullet. And this means the bullet has a little wiggle room to be self centering in the bore. And the vast majority of competitive shooters now full length resize,

 

[truck driver]

All these years I've been doing it right and didn't know it. The joke is on me because I thought I was neck sizing and wasn't because I believed what I read in the gun rags years ago.

 

[elkeater2]

Well, I'm glad I initiated a re-visit to this topic. I'm not so glad that I tend to overthink things and jump to conclusions. So.......the rest of the story is a thin piece of something stuck to the bolt face and hidden by the claw extractor!! :mrgreen: I mean just in the wrong spot and just thick enough and strong enough to keep the bolt from closing on those precision sized cases :grin: They were chambering just fine all along. Not sure what the mystery material is or where it came from, and don't care now.
EE2