Starting with a blackout

[Tom]

I bought a 300 blackout 10.5" radical upper along with a pistol brace. It has an 8 twist. I'm putting it on an 80%, so the sbr thing won't be an issue.
After reading lots here on the blackout, here's what I think I know.
1. 8 twist isn't fast enough for the Lee boat tail.
2. Pc is the way to go. I have smokes clear and black.
3. The alloy needs to be fairly hard not because of velocity, but pressure.
4. Noe moulds tend to be too big in the nose for an ar15.
5. Gc bullets without the check should be ok with pc. I'm not real sure I got that right.

How am I doing so far?
Forgot to add, I won't be using a suppressor.

 

[Ian]

1. False
2. True
3. False, AC-COWW alloy is perfect
4. True
5. True, for subsonic loads

Since you made the serialized part, you designate it to be what it is. You designated it as a pistol to begin with, with arm brace and never put a rifle/carbine buffer tube on it or long-barrel upper, therefore the lower is a pistol lower, not a converted rifle lower. If you put a shoulder stock on it, you then have an SBR and you'd better have a stamp.

 

[Tom]

Thanks, Ian.
Looks like I'm not ready to put it together yet. I didn't realize the buffer tubes would be different.
On the sbr issue, I thought you could go back and forth as long as it started out as a pistol. Obviously combining a short barrel with a carbine or rifle stock is a no no.
I thought I saw comments on the Lee needing a 7 twist, but the Greenhill calculators indicated 8 for 1,000 fps.

 

[Ian]

It's a grey area. If you register it as an SBR you can do whatever you want as long as you have the parts to return it to its registered configuration on demand, i.e. you have the original SBR upper with you all the time. If you "intend" to build a pistol, then it's always a Title 1 pistol, and pistol rules apply (no vertical fore-grip, no buffer tube that could possibly accept a rifle/carbine stock, etc.). I think you can put a rifle-length barrel on a pistol, but double check the atf's handgun definitions and the T/C lawsuit before doing so.

My Radical 10.5" upper puts powder-coated Lee 230-5R bullets into neat little ragged holes at 50 yards. The trick is to make sure the bullets are big enough, or they will yaw significantly. Mine likes .3095" minimum coated, sized diameter. .309" bullets gas-cut and tumble. The Lee bullets tend to case about .307" on the bands and .298 going up to .304" on the nose, so a thick coating, or some tin in added to your alloy, may be necessary. The Radical Blackout chambers and throats are a little on the generous side compared to most.

 

[Ian]

Here's how you build a compact, suppressed rifle with only one tax stamp (for the suppressor): https://www.artfulbullet.com/index.php?threads/winter-project.899/ Skip to the end and find a link where someone is now producing the shrouded barrel upper like I had to make.

 

[fiver]

that long LEE is iffy in an 8 twist.
if you run it on the edge of super sonic it may or not stabilize.
I personally would stay with something in the 200-210gr area just to be sure.
but a LEE mold is like 20$ and you can always take the boat tail off the mold if it don't work.
so trying it in your gun isn't like buying a 125$ custom mold and having it converted to a machine or adding a hollow point, running the price up over 200$.

the nose thing is also,, well?,, a maybe or not deal too.
I would say mostly the NOE's run too big, but I have also seen 3 different throat shapes/sizes cut into 3 different 300 BO rifles.
which is pretty much my entire sampling of them.
I do know if I load jacketed bullets to fit the AAC the rounds will fit the other 2.
the one rcbs bullet won't fit the ar rifle at all but does fit the bolt guns, one like a custom match fit and like a slop of glop in the other.

 

[Ian]

The Lee is borderline, but does just fine in both of my 8-twists IF I cast and coat it big enough to fit. The Radicals have no issue with the coated nose when loaded to magazine length (2.240" IIRC). My CMMG 7-twist does group better with them, though, but it also has a .309" throat entrance and the bullets fit the throat like a glove with barely any slop at all.

One thing you have to watch with the BLK and heavy subsonics is neck tension and crimp. Don't expand the case neck too much, and do apply some roll crimp in a groove. Don't crush it, but get a firm roll. Otherwise the heavy bullet will pull when the case shoulder hits the chamber shoulder and you may de-bullet the case if you unload it without firing.

 

[popper]

Long barrel is fine but if a carbine buffer tube make sure the bolt hole is permanently welded (or other means ) shut. Check the tube to make sure the spring/buffer don't bottom out, tube could be shorter. SBR is different than a pistol.
I shoot heavy PB supers PCd in my 1:8 pistol, works fine. No brace, just cheek the tube offhand. ACWW is probably OK for subs, I H.T. for supers. Experimenting with ACWW (& softer) now.

 

[Tom]

Well, I tried some dummy rounds with what I had on hand. The noe Saeco 315 clone, Lee 170 gr., and noe 311331 were all no go.
The noses on all 3 were too big.
The Lee was the smallest at .3009" .
The 311331 was cast with Poppers cu enhancement method 3 1/2 years ago and was .3015/3018.
The other 2 were cast with coww/ 2% tin.
Looks like I'll have to locate that .300 nose die I have somewhere.

 

[Tom]

I found my nose die, but it had a .301 bushing in it. The next size down I had was a .298 that I used for my Swede neck die. That made an absolute mess of the boolits. As little as I actually shoot, I'm probably better off with jacketed, but I like being able to do it myself, and the 300 blackout seems like a good cartridge for cast.

 

[Will]

Here’s a cheap on to try that a lot of people use
https://leeprecision.com/mold-dc-312-155-2r.html

 

[Tom]

After looking at pistol buffers at joebobs, and chatting with customer support, I'm thinking the spikes tube assembly with the t2 weight (4.05 oz) might be the right choice. Does that sound right?
Thanks for that mould suggestion, Will.

 

[fiver]

some of them want a .299 nose.

that LEE Will show's is a pretty popular one and is a handy mold to have around even if it doesn't work in the 300.
I really wish I would have had enough sense to snag up an HM-2 mold when we cut them from ED's original drawings, but figured I could always wander in and get one from the shop when I went down for my next visit. [I used to just snag one of the prototypes when I went to finalize the drawings]

 

[Ian]

I really wish I would have had enough sense to snag up an HM-2 mold when we cut them from ED's original drawings,

That makes two of us.

 

[popper]

I use a standard carbine buffer and spring but had to cut 3 coils off the spring to get lock back.

 

[Ian]

I use a JP extra-power polished spring and hone the machine marks out of the inside of the tube with a brake cylinder hone and oil. The threading die leaves a thread impression inside the tube which needs to have the high sides honed off as well. I also round the hammer nose slightly and polish it, and grease the buffer spring with a light, buttery synthetic lithium grease. Don't take too much off the hammer nose or it will double.

 

[freebullet]

No blackout, but my x39 will stabilize 200gr with 9twist. I'd be inclined to try it.

You can use a carbine or a2 buffer tube on a pistol, but it must be modified to not easily accept a stock. Not a big deal. One of ours wears an a2 tube. The threads in the end were drilled out. The rear lower detent hole was threaded & spring fitted with a cap head screw. Can't fit a stock now, perfectly legal.

If an ar pistol is above 26" length it can have a vfg, but that makes it a firearm(instead of pistol) & it cannot be carried concealed. Remove the vfg & you again have a pistol.

An afg is allowed on a pistol.

 

[Ian]

My 10" twist .308 stabilizes the powder-coated Lee 230 out past 200 yards using a 960 fps load of Titegroup and a large pistol primer. 7-twist seems to shoot a little tighter groups with it and always makes round holes, the slower twists are a little more picky. I've put somewhere around 1200-1500 of the PC Lees downrange in three blackouts and my .308, another 3500 or so of the ACE 230 flat bases, and they all shoot each one just fine. NOE made the ogive wrong on their 230 copy of the ACE mould and it's too fat to chamber when crimped in the groove on most BLKs. Powder coat it might not work at all. The Lee bullet is perfect for powder coating because it's too dang small to begin with and coating is the only way I can shoot it at all.

 

[Brad]

I have the NOE and it does fine in my Radical upper, carbine length.
It will engrave the nose farther from the case mouth than the Lee so it needs to seat a little deeper.
I have good results with 4227 at subsonic speeds.

I have fired the MP 30 Sil at over 1600 fps with good results too. Light rifle gets a little lively at those speeds.

 

[Tom]

So much good info here... I ordered the Lee 230 and 155 moulds, along with a pistol tube, and a .300 bushing.
Next dumb question: I bought the Lee factory crimp dies thinking of jacketed bullets. Do you think that would be ok for cast?