going from 5.56 to 300-221

[RWBlue]

How do I go from 5.56 brass to 300-221 brass? I would think someone has written this up, but maybe not.

I am not a wildcater, but I am experianced in reloading.

[DonT]

Using .223 brass (I like Winchester)
Deprime (I prefer to deprime all brass using a universal depriming tool)
Resize
Trim to length
Prime
Load
Repeat



DonT

[RWBlue]

Originally Posted by DonT

Using .223 brass (I like Winchester)
1. Deprime (I prefer to deprime all brass using a universal depriming tool)
2. Resize
3. Trim to length
4. Prime
5. Load
6. Shoot
7. Repeat



DonT

The link doesn't work.

I assume #3 is resize from 223 to 300-221.
If this is true, how do I trim?
I have a Wilson case trimmer setup for 308. I don't see a Wilson cartridge holder for 300-221.

[DonT]

Not sure how the wilson works, myself I use a 9" south bend lathe with a collet setup and stop. Makes pretty quick work of of trimming. I use a cutoff blade to get it close then switch to the lee trimmer. I used the 7.62X39 cutter and spud and ground the pin that goes thru the firing pin hole till I got the length I needed. I also had to turn the outside of the spud a bit as it was pretty tight in the case mouth since 7.62X39 is .311 dia. I think.

DonT

[RWBlue]

Are you telling me I need to get a

RCBS Trim Pro Power Case Trimmer Kit 110 Volt ?

Or is there a better option?

[jarhead1086]

I am planning on going this route myself after having gone from .221 and necking up. Don's idea of using a lathe is what I plan on using too and I am looking to make a shell holder that can stuff the lathe trimmed case into my Dillon RT1200 .308 case trimmer for the final trim. I will set-up on my .50 press to make sure I have clearance. Anybody try something like this yet? Maybe a shouldered collet in the lathe would allow you to skip the final trim and hold tolerance? I ordered some from Mr. Davis to get me going, but I need a bunch being a machinegunner. I plan on this being my subgun round.

[RWBlue]

By posting on a couple other boards I think I figure out a way to make this work without adding too much to my kit.

Starting off from once fired 5.56.
1.Run brass through Redding FL sizer (no neck expander), on Rockchucker press with Lee brass holder
2.Use Redding trim die, and dremmel to cut the majority of the excess brass off.
3.Use Wilson trimmer with 221 Fireball case holder to trim to perfect length.

At that point I can proceed to load like I would a non-wildcat cartridge.

Right?

[pug]

There might be some slight variation in case length between sized without expander and with so you may want to not final trim to exact length until you have run the brass through the FL die with expander. This may have been what you meant.

[RWBlue]

Ah, ha, so this would be better

Starting off from once fired 5.56.
1.Run brass through Redding FL sizer (no neck expander), on Rockchucker press with Lee brass holder
2.Use Redding trim die, and dremmel to cut the majority of the excess brass off.
3.Run brass through Redding FL sizer (with neck expander), on Rockchucker press with Lee brass holder
4.Use Wilson trimmer with 221 Fireball case holder to trim to perfect length

[pug]

I hate absolutes but that looks good. After steps 1 and 2 you are going to still have a primed case with a neck size of .304". The Redding die uses the expander to support the decapping pin so it will need to be installed to deprime the case and also to expand the case neck out to .306". Make sure you run the stem and expander down so it clears the neck sizing part of the die. I actually had a little problem on that last step with my first Redding 300/221 FL die that caused me some trouble but after a replacement stem from Redding all was fine. The sizing with expander should be as smooth as without. If any bind don't force it and readjust. All this is assuming you have a 300 Fireball chamber that lets you shoot 223 brass without turning the necks down (.338 chamber neck). If you have a 300/221, 300 Whisper or 30-221 your neck diameter (possible .335" chamber neck) with bullet seated may be a press fit in the chamber which is very bad for high pressure. You could of course could do a chamber cast and measure the actual chamber neck dimension or you can coat the cartridge neck with a marker or layout fluid and insert it in the chamber and see how much gets scraped off (if any). Then of course there is the age old "stick it in and see how tight it is" method but because of minimum spec cut chambers that is not a good telltale. Keep your brass length to the short spec unless you actually measure the max case overall length with a gauge.