Making 300 AAC Brass from 204 Ruger???

[XC700116]

OK so long story short, I have a bunch of 204 Ruger Brass that although only fired once is fubared in the neck area so I can't reload it for my 204 (long story but lets just say I'm suspecting it got fired in a 223 rifle and NO it wasn't me but I know it's only once fired). So I've kept in in the recycling bag.

The main portion of the case is in great shape and I'm getting ready to make a bunch of 300 AAC brass from 556/223 brass. Looking at the book the 204 brass is within .001" of .223 in every dimension that would be critical for making 300 AAC from it.

So my question is - Is there something I'm missing? It's looking like it should be no problem at all to make it work, and of course - Have any of you done this?

[Hoser]

I did that a while back. It didnt work out.

The brass in the newly formed neck area was way too thick.

This was Hornady 204 brass.

[XC700116]

Thanks for the heads up, this is also Hornady brass so I'm guessing it'd be the same issue.

Oh well, just figured it'd be a good chance to actually use it for something.

[XC700116]

OK, so I got my dies finally and formed up some from .223 and then for giggles I formed one up from the aforementioned .204 brass. And at first glance the neck thickness didn't look too bad until I took a Mic to it and I see exactly what Hoser was referring to.

It's a no go. Too thick, doesn't form that nicely, and probably would cause serious issues in the chamber unless it's way loose.

Hoser, thanks for the heads up on what to look for on it.