Consistency Concerns

[DIY_2A]

I am working on a 300 Blackout AR build and the price of ammo has drove me to decide to reload. I found a lot of information over the last few weeks, but when looking at molds I am confused about why 300 blackout is listed as a 308 diameter but all the molds are 309. Does this effect the boolit or not and if so do I just size it down with a sizing die?

P.s this is the mold I was wanting to use http://noebulletmolds.com/NV/product_info.php?cPath=30_341&products_id=768

[Cowboy_Dan]

You do want to size rifle boolits to fill the throat which is generally bigger than the barrel's groove diameter. I use .311 in my .30-30, personally.

[Soundguy]

Cast is almost always at least .001 over jacketed projectiles ( if not more ).

[DIY_2A]

Okay so the size difference is normal and should be fixed when sizing.

[Soundguy]

Even sized, the cast boolits are usually .001 over fmj.

Sizing ensures consistency ( and applies gas checks, and, if applicable, lubes the projectile.)

Depending on the die and the firearm, some people shoot 'as cast'.

For instance, 357 mag / 38 spl uses .357 diameter jacketed projectiles.

My lee tumble lube dies drop at .358 - .3585

I have used them as cast, but usually size to .358 & run them.

Thus , sized to .358, and .001 over jacketed diameter.

[DIY_2A]

Does being over effect performance?

I was planning on powder coating them since they are supersonic.

[Ford SD]

that mold you are looking at Some say is not very accurate
for cast bullets and a semi auto the best way to happness is slow and heavy
for the 300 AAC bo look for 165 - 247 g cast weight
using cast you want to use 309-310-311 dia
the problem arise if you are useing brass with thick neck
if you brass neck is 0.015 thick
bullet .311+.015+.015=0.341 Samm dimensions for the neck is .334

so for the above combination there is a high chance it will not chamber

for cast 95% of people use a gas check
you will have to use a flaring tool
high chance you will have to crimp neck after seating bullet
300Bo is best with 5-6 powders

[Soundguy]

.309 should work for him, with a safety factor, and yeah, I'd get a GC mold.

[DIY_2A]

So something like this would be better? http://noebulletmolds.com/NV/product_info.php?cPath=30_343&products_id=915

[jcren]

I don't cast for blackout, but I do for 3006 and several others, so while I will let the specialist recommend molds, I can say that when you start casting, throw out everything you think you know about what makes a good bullet. Lead is much softer than jackets, so bearing surface is a much bigger factor. Also, unless you are only killing paper, wider is better. Don't worry about the size thing, go .001-.002 or so over standard jackets and find what your gun likes.
Personally for a supersonic paper puncher, I would look at the
http://noebulletmolds.com/NV/index.php?cPath=30_342
Or one of the elco designs. Just Suggestions from someone with a few cool looking molds that are a pain to make shoot.

[Loudy13]

NOE 311-150-SP 311414 is an excellent mold for the 300BO, Cast loaded and shot 2000+ so far.

[dverna]

Many here will send you samples before you invest in a mold. Do a search and see what others are using....maybe PM them...offer to buy a hundred to test

Don Verna

[popper]

You mention reloading and casting. There are many jacketed bullets available inexpensively, some solid Cu. If you are set up for casting or just want to, NOE COD and the Lee BT sub aren't very good. I run 145-170 cast in both mine, LFN PB and they work fine. Guess I'm cheap have no intent to use GC in the BO. I neck turn all my brass - doesn't take much time and insures fit.