.300 Blackout--will I need a new expander plug?

[DaveSpud]

Just getting into casting for .300 Blackout. My molds arrived today: Lee 312-155 and 309-230. Also have the Lee .309 sizer for the .312 bullets.

For dies, I have the Hornady .300 Whisper die set. Am I going to need a bigger expander for my FL Resizing die? Or will the .309 boolits (sized) choke on the .308 necks? I have plenty of neck tension on commercial bullets, which I assume are .308.

And while I'm asking, how do you lube your .300 Blackout boolits? Do you have to use powder coating? Or is there a wax or alox blend that will do the job?

[jcren]

I am actually loading the Lee 230 blackout bullet for 3006, but I just use a taper punch to bell the neck, but you can certainly my use the Lee universal expanding die for a less red neck route. I have shot both powder coat and alox/jpw lubed in my 3006, but I am running reduced velocity around 1500 fps. I have read that Alox lube does not protect the gas system from lead vapor "condensation" but maybe one of the ar guys will chime in with experience.

[rockrat]

You really need to flare the case mouth a bit. I use a Lyman M-die for mine, but a Lee universal expander die might work.

[dh2]

I shoot the lee 230gr and a 144gr cast in my .300 AAC Blackout, it is the only cast I use my lee expander on I am sizing .310

[wlc]

I also shoot cast in my blk. I bought a 30 carbine expander die from Lee (cheaper than the Lyman M die) and bored it out for the BLK brass to fit. Works like a charm.

[xacex]

I put a expander plug for 30 carbine that is modified for the powder drop. I cant remember what I did, but I believe it was just drilling it out a little. Information about the conversion is somewhere in this forum. Sorry to be so vague, but I did this a while ago from information I gathered here, and haven't thought about it much since. Works like a charm! It flares the case mouth just a little like an M-die, and makes loading a PC boolit, or any boolit sized below .311 a breeze.

[popper]

Depends on you bore. I'd load a dummy really long with the 312, drop the bolt slowly and see what the bore marks on the nose. Add a thou. or so for your cast size. Add case wall thickness to see if the cases will fit, not all converted cases will work. I got one barrel that would take 311 but another that ONLY takes 3085. I coat everything now, no mess. HiTek should work for the subs, PC for supers. Also trim converted cases for your barrel.

[DaveSpud]

I loaded by first batch tonight, without a new expander. Maybe they fit because all the cases are nicely chamfered. Maybe because these gas-check boolits act like boat tails.

BTW, I'm trying without gas checks, first. Two different lubes. If I get lead, I'll add gas checks. Or, I'll get set up for PC.

[1johnlb]

I use alox sparingly, a very thin coat with no leading but my barrel is a cmmg melonite coated, to much alox and it will slowly gum up the bolt with alox. The only lead I've seen has been with anything other than copper checks at supersonic speeds. As long as you stay below 1300fps or so leading should be a non issue, also if your not having to flare your case mouths your boolit maybe to small.