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.

[RU shooter]

If it will feed that fat flat nose it will feed anything! As a general question to everyone ,Anyone tried a bullet that gave feeding issues Cast or jacketed? Everything I have tried so far fed just fine seated long,short and inbetween,RN,FN all feed all from my cheapo 3 dollar plastic mags even without trimming the ribs. I read alot over on the 300 BLK site and seem like a good may people have feeding issues with jacketed especially RN and FN Maybe my rifle isnt as temperamental as some?

[crabo]

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

Please do. I keep thinking about building a new AR and can't get excited about anything, but the 300 looks good.

What barrel do you have in yours?

[Elkins45]

It's the Midway AR Stoner 1/8 twist stainless. I've found a couple of cast loads that shoot well at 100 yards so far. One of them is the Midway custom Lee 230, but my first test load was so light it wouldn't cycle the action. I've also gotten good results with the Lee 150 GC and Accurate Data Powder 2200, but I hate seating cas checks. The NOE 311407 shoots acceptably, but I haven't found the right powder/charge to really get max results from it yet.

My Ranch Dog mold is 3x plain base and 3x gas checked. I'm crossing my fingers that I can find a plain based tumble lubed load that works---think of the time that would save!

[xacex]

I have the AR Stoner 16" regular profile barrel on one of my AR's, and it is a shooter! It seems all the barrels I have come across in the budget range are about 200$. I did find one company this week that is selling them for about 40$ cheaper, and had a sale on them this month for 120$.This weekend I hope to try the 8.5" CMMG in the pistol I just built. I have heard a lot of bad reviews about the CMMG, but mine came perfect. The bore was concentric, threads were fine, gas hole was .110, and it was dimpled for the gas block. If manufactures would bring the price down to that of the 5.56 barrels I believe more people would try this round. Maybe it is just me, but I just don't like the .223 for anything that a 10/22 in .22lr can do for less money.
xacex

[Moonie]

I've got the AR Stoner 16" as well and it shoots very well. We have had issues with magazines with different boolits, the 170gr Lee has some issues as it is very short and if it moves forward it can jam. The 245/247 has had some issues with some mags due to the profile. The 230 Lee seems to feed VERY well as the meplat is so much smaller.

[bruce drake]

In response to RUShooter's question about feeding issues. I had problems with 110gr RN jacketed (designed for M1 Carbine) as well as LEE's 150gr FNGC design feeding in my Deltacompany arms 300BLK upper with M4 Feed ramps. THey would hang up on the ramp everytime. I switched to Sierra's 130gr spitzer j-words and to Lyman's 311413 169gr Spitzer nosed boolit and have had zero feeding problems since.

Bruce