Considering a .300 Blackout pistol. Cast worthy cartridge?

[Tallbald]

Palmetto State Armory has some very attractive AR pistol kits in the .300 Blackout cartridge. I believe they are 1 in 8 twist barrels.And I have an unused Aero lower receiver. Casting for 5.56 doesn't right now interest me, but the 30 caliber is quite attractive. And I read that the cartridge can use 110 to 220 grain slugs, for great versatility.
I'm sure it's been done and I've read several threads about it, but now that the cartridge is becoming mainstream and there are a number of different powders new to the market, I'm wondering what folks here think of casting for this new darling of the sport? Cast slugs in a gas operated platform is completely foreign to me. Lube clog gas ports? Gas checks give troubles near the gas port?
I prefer to stay close to subsonic. Not because I have a suppressor, but because that's my favorite way of shooting.
Thoughts on the latest findings and experiences sure appreciated.
Thanks as always. Don.

[fatelk]

I use the Lee 160gr bullet, powder coated, gas check, moderate charge of H110 or 4227. It works great, shoots around 2 moa @100 yards. I've had zero problems with leading. It's way beyond subsonic. I suppose if you want anything remotely close to subsonic that will still cycle, you'd need a much heavier bullet. I've never messed with those myself. I'm not much interested in suppressors; it's more of a plinking rifle for me.

[scotner]

No need for a gas check mold if you are shooting subsonic but powder coat is definitely the way to go. I have shot nothing but these boolits in my 10.5" suppressed SBR with no problem. For powder selection I am loading h110 behind a 240 grain bullet. My mold is the Accurate 31-240a. I PC'ed a few today.

By the way, you may not have a suppressor now but if you ever thought about getting one this will put you over the top.

[sutherpride59]

I don’t have a pistol but I bout one of PSA’s 16” rifle kits a year ago and it’s a very easy cartridge to cast for. I’m waiting on a group buy mold but I’ve been using the Lee 155grn pushing to normal copper velocities.

[tsubaki]

I'm powder coating Lee's c309-160-R (166gr actual) and pushing with 18.5gr of AA2230.
My 7 1/2" barrel is producing 1315fps. This translates to about 480 ftlbs at 100 yards making it barely acceptable for my hunting purposes.
I've had zero problems with this load cycling in it or my 16" barrel.

Another load, 11.5gr of AA1680 and a 220gr jacketed bullet cycles fine and gets 1195fps in my 16" barrel but will not cycle in my 7 1/2" barrel.
I upped the charge to 12.0gr and got 1116fps out of the 7 1/2" barrel, still will not cycle.
Others I have talked to with a 10 1/2" barrel do not have cycling problems with this same bullet/powder combination.
There "might be" a cut off point in performance with using certain low powder volumes below 10". I'm eventually going to get some software to compare this but right now it's just a guess.
I'd suggest getting a 10 1/2" barrel and change the flash hider to a forward throwing blast devise and cast/powder coat away!

[Tallbald]

This is wonderful information to have. I'm bookmarking it too. With .300 Blackout running at the best I've found so far, about 52 cents a round, it would absolutely have to be a "roll-my-own -ammo" handgun. i confess that I bought a PSA 5.56 kit over the Labor Day weekend. I've never owned or shot an AR prior to assembling this one. Daddy was a Korean Era vet and had no love for what was, in the 1960's, an obscure platform with a sketchy history (to Daddy). Odd that it's taken 40 years since my beloved shooting mentor and friend died, for me to jump into the now vintage AR platform arena.
I turned 60 a couple of days ago, and have decided to expand my experiences with something completely new to me. The .300 Blackout would let me explore the AR platform with a versatile and forgiving round. Whereas at this point with 5.56 it appears I'm limited to shooting tiny jacketed pills very fast, you folks have further opened my eyes to some real fun!
As to the alloy for this cartridge: I have clip on WW ingots right now (Thank you The Captain--You're great to buy from). Must I strive for a harder mix when casting for an auto-loading firearm? A rather "newbie" question, I've been unable to find here the answer so far. Can I tumble lube the slugs and have good results or must I plate or powder coat? The answer does affect my plans for financial reasons.
Thank you all for responding so much. And wishing good things to all. Don.

[roharmon]

I shoot the NOE .310 230gr bullet with good results.

[tsubaki]

As to the alloy for this cartridge: I have clip on WW ingots right now (Thank you The Captain--You're great to buy from). Must I strive for a harder mix when casting for an auto-loading firearm? A rather "newbie" question.

My unknown alloy is about a BHN11, no problems so far but I’m powder coating.

[popper]

My 10" works fine even for fast supers. Might want to look at one of the blade type tubes, easier to shoot. You probably need ACWW for alloy. I run a 185gr GC with soft but the 145 & 175 PB use H.T.d alloy (1400 -2100 fps). I PC and have no problem with the gas system. Mine is just over 5# loaded, heavy barrel. Cost increase over pistol cal is just the 4x powder use so I'm about $10/100.

[scotner]

I am using COWW plus 10% lino for mine. Regarding powder charge, you will just need to see where the gun shoots best. Looking at my test target you can see that more is not necessarily better as the group closed up with less powder (minus one flyer). Also, regarding reliable cycling, be sure to get an upper with the pistol gas system if getting a short barrel. Google that for more info.

[Tallbald]

Thank you all. The PSA kits are pistol length gas tubes all I believe. The Saint from Springfield has an adjustable gas block in pistol length, but truly and unashamedly, I share that The Saint's a gun outside my financial grasp. For me this will be a range gun and dare I say a "toy" rather than something carried into a serious situation. Mercy forbid that change, but were it so, I would load heavy and hope for the best.
Thanks to those here I have what I need to know for my exciting plan. Thanks again.
Oh. $10/100 is quite affordable even for a man of my means. Don.

[KenH]

The trick to 300BO in subs is for pistol gas system. I've got a 7-1/2" setup which will cycle 170 grain cast bullets just fine when subsonic. With a 16" barrel and pistol gas system I had to use 230+ grain for reliable cycling when subsonic. I've shot very few jacket bullets, 99% have been cast, both gas checked and plain base. All subs are plain base.

[Tallbald]

The information shared here with me has made my decision easier. Thanks folks. I am currently following PSA ads for sales. Holidays are coming, and from my understanding, PSA sometimes runs great Black Friday Sales. But too, the elections are coming. Concerned about pre-election panic buying like back in 2016. These may be "the good old days" we remember in a couple of years. I'm like many others in my "get while the gettin' is good" thoughts. Thank goodness for recent powder and primer availability.
Don.

[Moonie]

We have an 10.5" SBR, a 16" Carbine and I have a 7.5" Encore Pistol barrel, we use a suppressor on all 3 of them, they are seriously fun to shoot. My 7.5" is a full bull custom MGM barrel, enough weight to feel like a 22LR when shooting subs with the suppressor on it.

[Tallbald]

A suppressor would be exciting to have. But I'd need to hit the lottery to comfortably afford one. And the closest to entering the lottery for me is driving on the interstate. Thanks. Don.

[popper]

It is not a toy, fine for close hunting and SD. I've been playing with cfe pistol and 110 to 175 gr cast with reasonable results.

[Tallbald]

I need to read about powder coating. I understand the benefits, but I'm used to tumble lubing and would like to learn if TL would be sufficient for .300 Blackout. Thoughts please folks? Don.

[scotner]

I need to read about powder coating. I understand the benefits, but I'm used to tumble lubing and would like to learn if TL would be sufficient for .300 Blackout. Thoughts please folks? Don.

I don't know that I would want to use TL with a gas system. At subsonic velocities the round is just a big pistol boolit but I would not think that alox would be good for the gas system. If you have the sizer die the only other investment would be the powder and a toaster oven. Most of us started with whatever oven was available at the local Goodwill or other thrift shop. There are also usually some available on Craigslist or FB Marketplace. $5 to $15 will put you in business there. Check the coatings and alternative section for tips on how to get into PC on a budget.

[tsubaki]

I need to read about powder coating. I understand the benefits, but I'm used to tumble lubing and would like to learn if TL would be sufficient for .300 Blackout. Thoughts please folks? Don.

You are already on your way toward powder coating and don't know it yet. The same type plastic bowl you probably use to tumble lube will be used in conjunction with air soft pellets to help the powder adhere to the cast bullets. Now all you need is a cheap toaster oven.

[Tallbald]

I didn't know it was that low tech or that you tumbled the powder onto the slugs. I expected the slugs needed to be static electrically charged and a powder gun used to apply even coats, like done industrially. And I remembered seeing a fellow neatly stand the slugs upright on a tray for coating, and thought "wow that's getting detailed". I did watch a video of a man powder coating last night. He said he was using Harbor Freight powder, and as you all have shared, tumbled them to coat, sifted out the excess powder, then poured them into a tray in a pile and heated them about 20 minutes. He went on to pour them again in a pile to cool, then separated them. Made me wonder if they stick together like melting then cooling Raisenets in a clump.
As said, I need to read and study this process here. I'm guessing the powder is the lube(?), since I've seen powder coaters size the slug after coating (understandable). I thought though the powder would be sized off in the process.
I appreciate you all sharing. TIme for more searched here on the forum. Don.