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After considerable frustration on my part, I have finally managed to get a new forum up and running. The forum includes two areas, one for area for 300 Whisper rifles and pistols and a second for reloading and ammo issues. I have a huge number of visitors that come to these pages each day so please drop in the forum and say "Hi" and share your projects!

Some Comments from JD Jones of SSK Industries!


300/221 Remington from 221 Remington Brass


My preference in dies is usually RCBS but I found that Midway USA sells 300/221 Fireball dies as a group D die set while RCBS would require a custom die order at a significantly higher price. I elected to get Redding’s Deluxe 3 die set what includes the full length size, neck size, and seat dies.

The image above is from Redding’s current catalog but the 300/221 dies come in the same type of box, a 7mm AND 30 caliber tapered resize buttons, allen wrench, and a spare decaping pin. In summary, everything needed except the shell holder and the equipment needed for any other cartridge.

The tapered size buttons make forming 300/221 brass extremely simple and once the 300/221 brass is formed it doesn’t need to be done again.


Cases for the 300/221 Remington can be made by necking and reforming 221 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 down to another. You should be aware of this problem and its potential dangers. Reaming or neck turning of the case necks may be necessary in order to produce cases that will chamber and function safely.


  1. Preliminary size using the standard 300/221 Remington F.L. Die with the 7MM tapered size button installed.

  2. Final size using the standard 300/221 Remington F.L. Die with the original 30 caliber tapered size button installed.

(Click to see Larger)

Quarterbore’s Sample Image….

    1. Remington 221 Fireball Brass
    2. Brass after 7MM taper size button
    3. Final size after 30 caliber taper size button
    4. A loaded 300/221 cartridge
    5. A 223 Remington cartridge w/ 55gr. FMJ.

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 .003" larger than the unfired one. If in doubt, consult a competent gunsmith.

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


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This page was last updated 03/07/06