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View Full Version : Case Neck Thickness 300/221 Fireball

mosigdude
02-09-2008, 06:28 PM
Hey All! Great Forum with tons of great info! I'm new to the forum and brand new to the Whisper (or clone) community but not new to the shooting or reloading world. I'm working on my first build, an AR platform, with a Model 1 Sales 300/221 Fireball upper shipped and on the way.

I'm trying to get ahead of the game and get plenty of brass ready, which I'm forming from Lake City 5.56 (223) with Redding Dies. I sorted about 1000 pieces of the same year headstamp, took some random measurements after sizing and all seem to be consistent. One thing I can't find is recommended neck wall thickness. Right now I have a neck wall thickness of .011 (which happens to be .001 thinner than some "test" brass I formed from RP once-fired 223) . Is this in range for this caliber or do I need to turn the necks thinner?

Any help is appreciated!

Edit: Sorry about posting this in the guns section, I was reading other ammo qestions when I posted and thought I was in the ammo / reloading section. I also located a similar question and answer regarding neck thickness which pretty much answered my question, but any additional info is still appreciated!
pug
02-10-2008, 01:28 PM
I have not had the opportunity to cast a m1s chambered barrel to get the neck dimension but if you are getting a loaded neck size of .330 with LC that is the size I look for. It is usable without any turning in all of the chambers measured so far. To date the tightest has been the PTG 300/221 reamer which cuts .3335" neck. Be aware that some military brass has measured .3345" loaded and wouldn't be ideal in such a chamber.
mosigdude
02-10-2008, 08:27 PM
I am between .3295 and .3300 with the few dummy rounds that I assembled, so hopefully I'm good. I'll do a casting on my chamber when it gets in just to make sure.

Now on to part 2:
I'm seeing several variations in the listed max case length, the longest being 1.400". I did an initial trim on my brass at 1.390" but can always go shorter if necessary. What is the "norm" trim-to length that most are using?