Need advice; buggering up cases trying to convert .223 to .300

[PFDD]

Update:

Amazing what happens when you run the expander button at the correct height in the die....!

Just tried two Lake City once fired cases and what do you know; smooth as butter with little leverage and far less lube required. The entire difficulty was induced (well by ignorance) but you've helped me through it and I appreciate the assistance.

Here are the Redding instructions for forming 300/221 cases using .223 cases:

CASE FORMING INSTRUCTIONS
300/221 Remington FROM 223 Remington BRASS
DIES REQUIRED:
1.300/221 Remington Form & Trim Die
2. #10 Extended Shell holder
3.300/221 Remington F.L. Die Set

BRASS REQUIRED:

Cases for the 300/221 Remington can be made by necking and reforming 223 Remington brass. It is desirable to use new unfired brass for forming. As it has not yet been work hardened by repeated firings, it is softer and easier to form.

There is always a potential problem when case forming from one caliber to another. The neck wall thickness may increase. You should be aware of this problem and its potential dangers. You may encounter this problem when making 300/221 Remington cases from 223 Remington brass. Reaming or neck turning of the case necks may be necessary in order to
produce cases that will chamber and function safely.

SEQUENCE:
1.300/221 Remington Form & Trim Die functions as Form #1. Cut and file off excess and then debur.
2. Final size using the standard 300/221 Remington F.L. Die.
3. Inside neck ream or outside neck turn cases if necessary.

CAUTION: A note of caution applies to "wildcat" calibers and all case forming operations.

WATCH THE NECK DIAMETER. If insufficient space is available in your chamber to allow the case necks to "open up" and release the bullet, very dangerous pressures can result. Any difficulty in chambering is a caution flag!
If possible compare the neck diameter measurements of a previously fired case from your chamber with those of a loaded round. The neck diameter of the fired case should be a minimum of .002-.003" larger than the unfired one. If in doubt, consult a competent gunsmith.

If you should have any questions concerning the above procedure, contact:

REDDING RELOADING EQUIPMENT
1089 STARR ROAD
CORTLAND, NY 13045
tech Iine@redding-reloading.com
REDDING-HUNTER INCORPORATED 1089 STARR ROAD CORTLAND, NEW YORK 13045 TELEPHONE: 607-753-3331

Thanks again gents.