Expecting a baby........300 BLK

[unforgiven]

Great job brother you have 300blkout down to a science. That rifle is amazing. 🍺🍺

[BrianK]

Even though it may look like a rifle it's actually a handgun unless registered as a SBR. Please don't give ATF additional fuel for their unconstitutional acts. 

FWIW, whenever I allow someone to handle my AR handgun, I explain that even though it may look similar to a rifle, it's actually a handgun by definition. I do that 100% of the time.

[Armed Eye Doc]

4 hours ago, BrianK said:

I do that 100% of the time

As of now, I have no AR pistols but I will be sure to give this advice as well.

[dpete]

UPDATE

I went to the range again today but this time for an accuracy test.  This build was never intended as a long range precision piece but I had hopes of decent accuracy.  It has achieved that.  The Fastfire III has a 3 moa dot which pretty much covers a 2" square on the target with my eyes.  With about 75 rounds through it so far, it is minute of baseball at 50 yards with bullets loaded for my 8" BLK sbr.   So far it is living up to the hopes I had when thinking about building it, a rifle round coming out of a package that is about the same size as an H&K MP5.

[98Z5V]

11 minutes ago, dpete said:

UPDATE

I went to the range again today but this time for an accuracy test.  This build was never intended as a long range precision piece but I had hopes of decent accuracy.  It has achieved that.  The Fastfire III has a 3 moa dot which pretty much covers a 2" square on the target with my eyes.  With about 75 rounds through it so far, it is minute of baseball at 50 yards with bullets loaded for my 8" BLK sbr.   So far it is living up to the hopes I had when thinking about building it, a rifle round coming out of a package that is about the same size as an H&K MP5.

.300BLK is a surprising cartridge, brother.  It doesn't things it shouldn't be able to do, ballistically.  I love the cartridge.

You've done things with this one that shouldn't be possible, but are.  It's a magic round, like Grendel. 

@JBMatt has a .300BLK that does things it shouldn't be able to do, as well.  It's just a damn good combination of .308 projectiles in modified 5.56 cases...  

Edited April 3, 2022 by 98Z5V

[BrianK]

Dittos what 98Z5V wrote, the 300BLK is an amazing cartridge. I would have accepted baseball size groups at 50 yards for my intended use, but instead got 1" and smaller groups from my 85gr bullets @ 2300 fps @ 50 yards with my AR handgun. But I'm not done with load development. I never thought the cartridge would be this amazing. I just wanted it to take the place of a 12 ga shotgun for HD and I got so much more. 

[dpete]

@BrianK  I got to the range today to do some velocity checks with the 4 Blackouts that I have in the house.  Bullets were 110gr Varmageddons and all were 5 shot groups.

16" barreled Ruger American Ranch bolt action averaged 2502 fps

10.5" pistol AR averaged 2270 fps

8" SBR AR averaged 2176 fps

This 5" pistol AR averaged 1858 fps

Bullets were randomly grabbed out of an ammo can and loaded into 1  30 rd pmag.  It was interesting to watch the velocity drop as the barrels got shorter, which was completely expected.

Edited April 11, 2022 by dpete

[BrianK]

Thanks! 

That reinforces my belief that the 10.3" barrel for my HD handgun is one of the 2 optimum for my usage, but 8" also would have also worked for me and made for a smaller handgun. Or put into other words getting the most I can while not having an overly long handgun when the can is on it which is pretty much 100% of the time. Except when I'm developing a load, then it wears a blast forwarder just in case of bullet instability.  I could have had a handgun with a 12" tube if I had gone with an 8" barrel, since the can adds another 4" to it.

If I built it for hunting I would have gone with a longer barrel.

I'm actually surprised that 3" more barrel yields that much more velocity.  (5" vs 8"= 318 fps but that's what the "book" states in general for rifle barrels)

Would I want to be hit by a bullet out of the 5"? No. I think it would hurt.

[dpete]

33 minutes ago, BrianK said:

Would I want to be hit by a bullet out of the 5"? No. I think it would hurt.

Hurt?   These things are varmint bullets and even at lower BLK speeds they basically explode after entry.  Getting hit in the chest would result in everything in there turning to mush.

[BrianK]

Yeah. It was my way of downplaying it. I hate a mushy chest. Never had one but I just know I wouldn't like it.

[Rsquared]

My 300 BLK SBR is using a 10.3" Noveske barrel, with an older EoTech 553 on top of it. That thing is hollywood scary when shooting subs out of it suppressed. And it is absolutely deadly at short to medium range (where it's intended to live). This was what first got me interested in the cartridge. It's got some great accuracy at the close ranges. Plus the ability to step up to supersonics, and step out to farther distances (relatively).

[dpete]

25 minutes ago, Rsquared said:

That thing is hollywood scary when shooting subs out of it suppressed. And it is absolutely deadly at short to medium range (where it's intended to live).

Yup. Mine too.  Plus the subsonic BLK bullets designed specifically for hunting do scary things inside deer.   Subsonic hunting is like bowhunting with a rifle, close in and quiet.  You hear the shot, then a fraction of a second later hear the bullet hit the side of the deer.  It sounds like someone slapping a pair of leather insulated mitts together.

[BrianK]

dpete, is that a Maker bullet? I think I recognize the 3 petals. If so I load his 85 grain bullet to 2300 fps to limit penetration but maximize ft/lbs for HD. But anyway, interested in the bullet and load data for subsonic.

[dpete]

@BrianK   Yes thats a 200 grain Maker subsonic.  The only bullet I've used for Sub hunting.  I've also got 225 gr Hornady HPBT and 220 SMK for paper punching.  All three of them have almost the same point of impact at 50 yards with their respective loads.

These subsonic loads are what my 8" suppressed SBR likes. As always YMMV.
220 SMK in LC case.  9.7gr IMR 4227.  CCI 400 primer.  2.220 COAL
225 Hornady HPBT in LC case.  8.8 gr IMR 4227.  CCI 400 primer.  2.220 COAL
200 Maker HP in LC case.  8.4 gr IMR 4227.  CCI 400 primer.  2.120 COAL

All three of these loads are 970-980 fps which is the speed range this barrel likes. Yours will most likely like something else.

 

I tried using Lil'gun when I was first doing load development.  It worked just fine but I found that IMR 4227 was more accurate and much cooler burning.  My subsonic BLK magazines are standard 5.56 Pmags with the entire inner side rib filed out.

 

Rifle with mag.

 

mag in rifle

 

Top view of mag

 

By taking the ribs out completely these long fat basterds can be loaded to mag length instead of having to fit between the ribs.  They become dedicated sub mags by doing so because shorter supersonics would rattle around front to back in the mag not having the rib there to hold them.

Top

[DNP]

[BrianK]

Thanks. That's nice expansion even at that velocity.

My loads will definitely be different. I don't have 4227. But I have other powders that I can use. 

[BrianK]

I forgot that I can't leave and come back to edit a post on this forum. So I'll ask my question here. Sorry, this post has me demonstrating that I can write endlessly. But I'm leaving it as is.

How much penetration did you get with that Maker load? I'm just curious. I can't get out into the woods anymore so it's not a hunting question. If I shot a deer in the morning it would take me until the next day to drag it out. Aging and everything that comes with an aging body isn't for sissies.

I'm using the 85 gr Maker because I don't want an exit if I ever need to use them for HD. If one graphs the depth of penetration based on velocity it's a bell curve, penetration increases as velocity increases and becomes less once one goes past a threshold. I forget the numbers but @2300fps and 1000 ft/lbs I would expect the bullet to stay in a 2 legged maggot at HD distances. I know I wouldn't want to be hit by one. But then I wouldn't want to be hit with a .22 rimfire short. Accuracy with them is fine, <1" @ 50 yds. Much better than I need. 

Paper punching... I cast a few hundred 220s last fall, had them all ready to load and was just waiting to develop a load. I must have put them in a very safe place to prevent riff raff from finding them and walking off with them. Only now it turns out that I'm the riff raff. I can't find them. I also got a new mould for 150s. I'll cast a mess of them and the plan is to load them both super and subsonic. But it depends on performance. I'd like to get a load or loads that I can use for an unsanctioned match that is said to be an ongoing yearly event. I'd like to use my arm braced 300BLK handgun for it. Last year some targets were out near 200 yards, so supersonic would be great.

I'm trying to remember what powders I have that would be suitable, W296, Lil'Gun, N120, a small amount of A1680, Trail Boss, and I think I've seen data for Power Pistol, and another that escapes me. I should be able to work something up. 4227 I don't have.

Mags... When I built my handgun I saw 300BLK Lancer mags for the same price as 5.56 mags and wanted more 5.56. So I bought the 300BLK specific mags and that freed up 5.56 mags. My understanding is that they have stronger springs and the offending ribs have been moved or are totally gone. I examined them and compared. I just forget what I saw. Would I use them for 5.56? No. 

Oh well, enough rambling. 

[dpete]

2 hours ago, BrianK said:

 

How much penetration did you get with that Maker load?

 

The deer taken with the bullet pictured above was standing facing me at about 30 yards.  The bullet entered between the right shoulder and brisket, travelled through the chest cavity, and lodged inside the stomach.  As I field dressed the deer I noticed a 1" roundish hole in the front of the stomach and cut it open to do a search.  (thank God for gutting gloves).  Feeling around in the goo I found the bullet.  It had travelled 20" or so before stopping.

I've taken 2 other deer at about 30 yards with the Maker that were broadside shots and both of those were complete pass throughs.  None of the three deer left any blood trail at all despite the nasty tearing edges after the bullets expands.  In my experience you don't track a deer shot with a sub, you look for a dead deer.  At subsonic speeds these bullets don't produce any hydrostatic shock that turn internal organs to mush. 

[98Z5V]

6 hours ago, BrianK said:

I'm trying to remember what powders I have that would be suitable, W296, Lil'Gun, N120, a small amount of A1680, Trail Boss, and I think I've seen data for Power Pistol, and another that escapes me. I should be able to work something up. 4227 I don't have.

Any powder that works for .30 Carbine, works great for .300 Blackout. 

[BrianK]

Thanks gents! I'm so glad I decided to go with the lightweight option dpete. When I was deer hunting I too picked my shot instead of shooting at the entire deer. "Aim small, miss small."

[dpete]

@BrianK    Trailboss works great for lightweight subs but only in a bolt action.   Its my go to powder for my 110gr subs because its so fluffy that the tiny charge fills the case.  4.4 grains gets me to about 980 fps out of my Ruger American Ranch bolt action.  It doesn't create enough gas to run the action of an AR15, but in a bolt its bunny fart quiet.

[BrianK]

OK, so Trail Boss is out for the 300BLK. Maybe it'll work in the .32/20.

[dpete]

4 minutes ago, BrianK said:

OK, so Trail Boss is out for the 300BLK. Maybe it'll work in the .32/20.

Scroll down to the video link. 

 

[BrianK]

Yeah, my only 300BLK is an AR. My .32/20 is a Contender (.308 bore) and should be fine with it. 

I tend to think of them as the same cartridge even though they are very different. 

BTW, that was a good video.

[BrianK]

On 4/16/2022 at 4:05 PM, BrianK said:

Paper punching... I cast a few hundred 220s last fall, had them all ready to load and was just waiting to develop a load. I must have put them in a very safe place to prevent riff raff from finding them and walking off with them. Only now it turns out that I'm the riff raff. I can't find them. I also got a new mould for 150s. I'll cast a mess of them and the plan is to load them both super and subsonic. But it depends on performance. I'd like to get a load or loads that I can use for an unsanctioned match that is said to be an ongoing yearly event. I'd like to use my arm braced 300BLK handgun for it. Last year some targets were out near 200 yards, so supersonic would be great.

The great missing bullet caper has been solved.

It finally dawned on me that the container I had them in is empty. So today that finally settled in and I looked in my loaded ammo. Sure enough there they were. I don't remember load testing them and I would have had to do that. Aging is so much fun! Like soft serve joey, I too can hide my own Easter eggs!