I've recently purchased an RCBS neck sizer die for my .223 Remington. I put it to work the other day and took out my once fired Winchester brass and neck sized them. I put together 10 cartridges of one of my tried and true loads to see if I could achieve better accuracy with the neck sizing process. Before I travel 30 minutes to the range I always chamber them in my rifle to see if they will feed and chamber properly. Well this time instead of a smooth chambering, I got a different result. This time the cartridge acted like the bullet was seated out so far that it was jamming into the lands, in other words the bolt would not close. The same C.O.A.L load that was full length resized instead of neck sized chambers perfectly. I am extremely oblivious to what I am doing wrong, anybody have a solution?

Sounds like the shoulders have moved foreward. Either the expander ball has enough drag to pull them out or your loads are pushing them hard.
Try lubeing the mouths when resizing and see if that reduces drag. It should help your problem, although sooner or later you will need to "bump" your shoulders back a touch.

I currently lube all case mouths and necks when neck sizing. Could it be that I have the neck sizer die set to low? I have it set right now that it is firmly touching the shell holder. Should I back it off 1/2, 1/4, 1/8 turn? What do you suggest?

Braxton

Nope the sizer goes down hard.

If you bumped the shoulder it would do what your saying.

Did you make sure you didn't contact the brass when seating your bullets.

Mark the necks of your cases with a Sharpie and you should be able to see if the entire neck is being sized. You may/may not have to touch the shell holder. Remove the expander ball when you are doing this and try them in your rifle. Replace the expander ball and try some other cases. That should answer your question. While you have the expander ball out of the die, polish it to a mirror finish.Rick.

i would try chambering a case you have neck sized with out seating a bullet. if that doesn't work just try rechambering a fired case that hasn't been sized at all

Ed

I'm currently neck sizing for 6mmbr,308 with Redding dies..
The 6mmbr likes only 2/3 of the neck to be sized.
Early on I thought that more would be better and neck sized down to the top of the shoulder.
A few thousandths too low and the neck die bumped the shoulder down and the case bulged very slightly just below the shoulder.
Just enough to prevent chambering.
Resized with the body die and raised the neck die,problem solved.
As Rick Smith said, Sharpie a few necks and adjust carefully, test fit in your chamber as you go.
You probably won't need the whole neck sized for consistent bullet tension anyway. Good Luck!

SniperAce016,No need to have your NS die turned down that far. Back off some.

Good luck.

So FIRED unsized cases go in just fine, right? You are apparently bumping your shoulder and getting a "doughnut" right at the top of the case body. That happens if you aren't sizing the case body at the same time.

Benchresters might tell you different, but I set my neckers as follows.
Put die in press, screw down most of the way, but at least a quarter inch high.
Set deprimer rod so expander ball is below neck, but not far enough down to hit primer and start pushing it out. Or, just pull the decapping pin for now.
Put case in shellholder.
Run ram to top. Shell should not touch die.
Spin neck die down until it touches case.
Drop ram down. Spin neck die down 1 1/2 to 2 turns. Run case back in. Pull out.
Examine neck, see if it is nice and concentric. If your brass is bad, might not be. Decide if this amount of neck sizing will hold your bullet (judgment call). If so,
Run another case into the die. Spin the expander ball down until it hits the bottom of the case, then come back up three turns or so to make sure the ball won't bottom on the base later.
I usually leave the decapper pin alone, and fiddle back and forth to find the right pin setting after popping the primer by running the rod/ball/pin assembly way too far out.
Further, whether I run the pin "high" or "low" depends on how the back-stroke of the ball out of the case neck feels. As long as the primer gets pushed out, running "high" seems to be smoother.
Now, pull the ram back down until the ball is pulling on the neck, then set the nut on the decapper. Run her back up one more time, then set the big nut on the die body before pulling back down. When you pull the case back out, there should be enough "load" that the nut will tighten up against the press or die plate.

It seems to me that with good brass, sizing half the neck is plenty of neck grab, and the "second shoulder" in the neck is just another way to center things up.

Dave..... you got it, right on the money... also the "doughnut" is the exact problem, had the same thing on a .204 ruger.

There is no point in neck sizing below the base of a seated bullet. Jamming a neck sizer against the shell holder CAN cause exactly the problem you are having IF it's chamber is cut short enough to allow die to case shoulder contact. Back off. Number of turns won't matter, just far enough to prevent shoulder contact.