300 AAC Blk

[vondelta]

Hello All,
I am very new to casting, as in I am still researching what equipment I want to start out with. The first question that I am needing help with is this:

I have a 300 AAC Blk rifle that I am wanting to cast 200+ Gr subsonic loads for. The SAAMI spec is that this is a .308 boolit. However, I notice a lot of people buying .311 molds for casting their boolits. Can anyone tell me why they are buying molds 3 thousandths larger than the bore is supposed to be?

[Wayne Smith]

Simple answer, you can size down but you can't size up.

[Moonie]

Also note that best accuracy is normally obtained by boolits slightly larger than the groove diameter, usually .001 to .002 over groove is found to be the most accurate. There are exceptions and only your barrel will tell you what it likes.

[P.K.]

Don't forget to slug that sucker too. That way you know w/o a doubt what you need.

[UtopiaTexasG19]

Many of us cast a bit oversized for our 30-30 Winchester loads. My Marlin 336 likes a slug at .310 and is more accurate at that diameter.

[Marlin Junky]

Hello All,
I am very new to casting, as in I am still researching what equipment I want to start out with. The first question that I am needing help with is this:

I have a 300 AAC Blk rifle that I am wanting to cast 200+ Gr subsonic loads for. The SAAMI spec is that this is a .308 boolit. However, I notice a lot of people buying .311 molds for casting their boolits. Can anyone tell me why they are buying molds 3 thousandths larger than the bore is supposed to be?

We're fitting throats.

MJ

[Idaho Sharpshooter]

It's called "Pressure Fitting". An undersize (for the throat) boolit gets expanded to fill the throat, then has to swage back down to fit the interior of the barrel. Up and down pretty much destroys and hope of accuracy.

Rich

Welcome to the Club!!

[fcvan]

I have been eying the 300 blackout just because I like shooting cast (although I cast for .223 already) It would seem that a good fitting 200-220 gr boolit at subsonic wouldn't need a gas check if everything else is right (fit, lube, powder choice) and a 120-125 gr at higher velocity would benefit from a gas check. Who knows, I may have to just break down and build an AR in this cartridge. Frank

[Tank56]

If your loading sub-sonic you don't need a gas check design. You can get great accuracy and very quiet performance with Unique powder, but it will not cycle an AR. I use IMR 4227 and a Lee 200 grain gas check bullet (I owned the mold for use in .30/30, .30-06 and .300 mag, before I got the .300/.221). Most people have good luck with H110 or W296.

[Moonie]

AA1680 is the preferred powder for subsonic loads in AR's. H110/W296 are hit and miss with subsonic loads. Some will some won't, my sons will usually, mine won't.

[bowfin]

Doe anybody use this cartridge who doesn't have a silencer?

[Tank56]

yes, one each way.

[Elkins45]

I don't have a silencer. I like it because it lets me shoot cast in my AR without having to buy special mags and a new BCG.

If I ever splurge and fill out the paperwork for a silencer it will be for a 22 before a .30 center fire.

[Moonie]

I don't have a suppressor, neither does my son with a 300AAC.

[RU shooter]

I shoot without a suppressor also, its a great little ctg for cast bullets

[xacex]

I really like this round. It is cheaper to shoot than .223 if you cast because you use about half the amount of powder,and you still can use range pick-up .223. Not to mention casting your own saves over purchasing J-words. Just be careful, before you know it you have 1000lbs of lead stored up that you spend hours scrounging for, and 15 custom molds that run 100$ a piece or more.
xacex

[fcvan]

XaceX, no truer words have been shared! I somehow keep acquiring more molds and still have my eyes on a few more. I am even considering making a mold for paper patching with an adjustable base just because I think it would be fun to try. I sure have spent a lot of money so that I can save a lot of money! Frank

[leadman]

The advantage of a gas check at sub-sonic velocities in the AR would be the rate of fire.

[crabo]

Anyone using the RanchDog 165 RF in the 300?

[Elkins45]

Anyone using the RanchDog 165 RF in the 300?

I'm getting ready to. I'll post results as soon as I have them.