300 blackout brass to 221?

[ba_50]

Since the 300 is based on the 221 I should be able to use standard 221 dies to reform it. Anybody done it?
Thanks

[BK7saum]

it will likely be short. 300 blackout is 1.6". 221 is 1.4"

[adcoch1]

Did one the other day to test out the new(used) dies I just got. couldn't find my caliper to measure length though, gonna try to look into it again tomorrow.

[rockrat]

300 blackout is 1.368" and the fireball is 1.4", so you will probably be a bit short.

Note--it will be short. Just ran one thru my 221 die and it came out to 1.366" long, so you will be 0.034" too short in the neck. It would work, but you might have to ream necks, depends on your chamber and brass neck thickness.

[ba_50]

Maybe they shortened the fireball case? It doesn't sound like much difference.
I don't turn necks anyhow.

Thanks for trying one.

[BK7saum]

Depending on how generous your chamber is or is not, you might not have a choice on turning case necks. If too thick, you will end up with high pressures. But if your chamber is generous, reform cases might work just fine.

[Conditor22]

300 BO comes from 223/556. why waste/play with 300 bo brass when a 223/556 are plentiful and will work?

[ThomR]

I'll trade you 223/556 brass for 300 blackout brass. Why waste 300 blackout brass?

[gnostic]

I make 221 Fireball all the time out of 223's, by running through a trim die. You'll have to neck ream them or they'll be way too thick...

[Texas by God]

Free basic brass for the win. Save the .300s for .300s; use.223 for making .221s if you can't find them.

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[15meter]

Free basic brass for the win. Save the .300s for .300s; use.223 for making .221s if you can't find them.

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Unless you have a 221 Fireball and not a 300 Blackout and pickup range find 300 blackout brass for free

And your Fireball likes really, really short brass.

[DocSavage]

If you can't find 221 Fireball brass you could reform 17 Fireball then no need for neck reaming.

[dale2242]

Lapua makes excellent 221FB brass.
I`m using it in a custom rifle.
It`s a little spendy but better than trying to form brass from 223.
At least it is to me.....dale

[Greg S]

What Dale said. Made 300 221FB from new Win brass. After trimming and neck turning, time and money spent, Lapua brass is nice. Worth it in the long run.