loading the 300BLK

Too funny! This is the 2nd time this has happened. I ordered some Maker (that’s a brand) .308 85gr copper bullets. Each time it was out of stock and backordered at the time of order. Each time they shipped the same day. The 2nd time was today and they shipped in under an hour. I loaded 1/2 my stock today and I think they’ll do what I want so time to get more for a production run in the near future. I think they keep them perpetually out of stock to turn away the riff raff.

The backstory on them… I was going to develop a short 12ga slug load for a new(ish) Keltec KS7 pump bullpup shotgun. The short story is that’s going to take time and I want something better suited for home defense than a 9mm PCC or even a 5.56 rifle with a can. The long gun is ungainly. Plus the 7/8 ounce slug might overpenetrate and I really don’t want to redecorate the house. These Maker 85s shouldn’t overpenetrate. They’ll also be not quiet so much as have no blast since the handgun was designed around the use of a can (that would be a silencer but that’s a misnomer). Well technically it IS a handgun according to the ATF! It’s also homemade. I made it when components were hard to get, but used connections to get the serial numbered lower and went high end for the rest of the parts. I had no waiting while Seattle, Portland, and other left coast cities burned. High end is nice since I had at least one manufacturer tell me that they would make what I wanted. It looks a little different today with a smaller, lighter sight.

The link below for more on the bullet, expansion, velocity, etc’… I include the link for the first post only.

http://www.300blktalk.com/forum/viewtopic.php?f=128&t=109552&p=1008517&hilit=maker+85&sid=8b25082f62040790fc83e2ed5fbb248b#p1008517

But why the 300BLK? It was developed as the .300Whisper and reverse engineered by AAC as the 300BLK. Sure the 5.56/.223Rem can be made subsonic, but it can’t function a semi-auto for repeat shots AND be subsonic. Many of us have tried and no one has ever been successful. But the 300BLK has heavy enough bullets to keep the pressure up long enough to open the barrel port and function the gun. The only thing needed to use the 300BLK in an AR-15 is an upper, or a barrel to convert a given upper to 300BLK. Everything else can be the same. But note that some bullets require heavier springs in the mag’ and a different build inside the mag’. But those 300BLK mags are available.

Today I spent some time with it working up loads and I was able to push it to about 2400ish fps. The thread linked to above suggests 2800fps, but that velocity wouldn’t interest me even if I could get it there. I’m using military brass and that just doesn’t have the same capacity for powder as civilian brass does. But my goal was 2200-2400 fps to limit penetration while keeping ft/lbs somewhat “up there”. I can also download it to limit penetration but that also drastically reduces the ft/lbs transferred to tissue. That’s not my goal. There is a 100ft/lb difference between 2200 and 2400 fps, so I’m hoping I can get a decent group at 50 yards with the 2400fps load. It’s really a short range round with this light bullet and 50yds is OK but stretching it. But it’s where I’ll test accuracy. It’s not bad for a 10" barrel.

Today I just loaded 2 rounds each from 19.0 grains in .2 grain increments up to 20.0 grains. Just to test for velocity and pressure signs and I got none. But I got a good look at the velocity window and loads above 19.6 grains showed no significant velocity increase. So why waste the powder? I loaded 10 rounds of each for accuracy testing. If I get a 3" group @ 5o yards that would be all I require. Then I can move on to heavy subsonic bullets (think shhhhhh! ).

The 300BLK (.300 AAC Blackout) is a reloaders dream since it will do so much. Supersonic with lighter weight bullets and quiet subsonic loads with heavy bullets. All allowing semi-auto function interchangeably. I already have supersonic 180s, but 180s aren’t heavy for the cartridge. Think up to 260+ grain bullets. But since there’s a cap to subsonic the only way to add ft/lbs is to add mass to the bullet. While slow bullets don’t have huge shock they have huge penetration.

The cartridge even with a 10" barrel is capable out to 200 yards with the right ammo. Just not with the ultra light weight 85 grain bullets and not with subsonic ammo. It should be fine with 125 grain ammo. That’s also in the test queue. Maybe ultra high velocities too with sabotted .22 bullets and ultra fast for the caliber powder, but they might not function the action. I did that with .308 Win and got 3600fps out of a 14" barrel. The blast was sort of spectacular and no pressure signs. I wouldn’t expect that velocity from the tiny 300BLK case, but 3000+fps might be doable.

I have 40ish Maker 85s left and 150 more shipped today. That’s plenty for what it’s for. I have other lightweight (125s) and heavy copper expanding bullets and jacketed non expanders and I’m going to cast my own heavy bullets. Again, think quiet for the subsonic bullets. But they are relatively short range due to the rainbow trajectory. 125 yards is doable as long as accuracy is there but range estimation is important. With a 50 yd sight in they drop 6" at 100 yards and drop pretty fast beyond 100 yards. But did I mention how quiet they can be? I like quiet alot of course with a can. Or supersonic with a can. No one can tell where the shot came from since the sound travels 90° to the travel of the bullet and without the noise of the shot that’s all there is to determine origin.

If one wants raw .30 cal velocity and power the 300BLK is not that cartridge. In the AR platform (and magazines) the .300Ham’r might be more inline with that desire, and of course there is the 7.62/.308Win or the .30/06 also in .30 but other platforms.

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I’m sitting on a ton of Hornady 150gr SP Interlock that I was reloading as a hunting round for my 30-06. If I could only get my hands on some small rifle primers, I’d love to test that round out with a sub-sonic load for my 300BLK. The 150 with the soft tip would expand and not over penetrate and still have knock down power.
If anyone knows where I can get me hands on SR primers, please reach out!
Until then, my ball peen hammer thrown at 94fps still fits the bill!

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Most .30 bullets are not designed for the 300BLK velocity window. 300BLK is just too slow. But copper jacketed lead varmint bullets are known to work nicely. Some much better than others. And of course there are the copper bullets designed to work for 300BLK (Maker and Lehigh are 2 that I know of that make them).

A call to the Hornady engineers would tell you the window at which your bullets expand. It’s not just the lead to consider but the jacket. I doubt that they will expand but I’ve been wrong before and I would like to be wrong here. But a call would confirm. But even if they didn’t expand a well placed bullet drilling a .30 hole through a brain or heart is deadly. But you’d need to pick your shot and know your capability for a certainty.

If I was still capable of going into the forest I wouldn’t hesitate to hunt with a non expanding bullet from the 300 BLK. But again, one needs to know ones limitations and pick the shot. (Aim small miss small.)

I have 700+ 200 gr Rem’ bullets that I know won’t expand. That doesn’t make them worthless. They’ll still drill a deep .30 hole and do so subsonicly. The cast bullets that I’ll be making also won’t expand. Expansion isn’t everything. In fact it’s a fairly recent development. Bullets worked long before reliably expanding bullets came on the scene.

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:+1: All about proper shot placement.

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I absolutely love the 300 Blackout.
I’ve posted some of my experiences with it in other threads.
My pistol absolutely loves the 125gn Hornady’s, and the terminal results I’ve had with it have been impressive so far.
Still waiting to hit a coyote with one, but my last kill was a very large jackrabbit at either 65 or 85 yards (I need to go find my data) bullet left a dime size entry hole and never exited. Dropped the jack like flipping a switch. It’s my go-to home defense gun now :sunglasses:

(Distance on the jack was 85 yards)

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My preferred CQ round.

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Not sure why but almost every bullet and load I have done with 300 is very accurate, from 110 to 220 with various powders, 308 is same way, hard to make a bad load for either one, never used anything below 110 grain. Ruger Ranch is only 300 I own and shoot.

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I don’t think you can get 150s subsonic and get the gun to cycle. In semi auto most subs are at least 200gr.

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I missed that about subsonic. Unless there is a can in use why bother with subsonic 150s at all? It can be driven faster to get better performance. Maybe she doesn’t want anyone to know she has a can? But it’s registered if it’s legal so that info is already possessed by the worst of people. I’m aware that subsonic even w/o a can is quieter than supersonic.

Off Doras subject… Is the 300 blackout forum still operating? I haven’t been able to post anything on it for a few weeks. Maybe I inadvertently ran afoul of their rules (I doubt it) or maybe they’ve been hacked. For awhile I thought the person who ran it has been burnt out. Maybe he gave up?

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The heavier the bullet, the slower the MV. But, this is also why all my AR’s have adjustable blocks. Running suppressed with a lighter grain round would not be an issue at the higher MV. The Hornady 150 SP Interlock works well on game with tough hide. It’s just a matter of working out the load to stay subsonic and keep that round stable out to longer distances since it’s not a boat tail. But, for self defense most shots will be at much closer range. You just can’t shoot them in the back as they are running down the street :pensive:.

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So far, all of my loads have been rock solid and spot on target every time! With a 5" barrel, target acquisition and response time is quick and easy even while on the move. I have yet to run and gun at distances over 50 meters but for now I’m just training CQB. Loving those 300BLK double taps!!!

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Use an adjustable gas block.

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Even w/an adjustable gas block wide open if the round doesn’t produce enough gas to operate the action before the bullet leaves the muzzle it won’t cycle. That’s why the sub loads use the heavy bullets. It takes more gas pressure to drive the heavy bullets.
Good luck w/your 150’s

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I hope you’re successful. Good luck.

Dora we’re attacking the issue from different directions. I like to KISS. I want to adjust my round to my gear and make the gear work for everything I shoot with no adjustment. I don’t mind fiddling with something if it’s a range gun. But for serious use I want to remove as many variables as possible.

Yet. That day may be coming.

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Thanks for the info! If I can just get my hands on primers I’ll be able to test these out.

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Finding that one load that works at any range, any conditions is always best. No need to make adjustments on scope or gas. But sometimes, like in this ammo shortage, you have adapt to conditions. And that’s where my ball peen hammer comes in.

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On 300BO the pistol length gas seems to work w/super and sub sonic rounds. Without needing to adjust the gas block. There is a big section on this caliber at www.forum.308ar.com

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My 300’s seem to shoot the factory deer season XP pretty well. Haven’t killed a deer with any yet but if i ever hunt in the woods i’ll take it. i get too long a shots for it now.

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Pistol gas is perfect for 300…and you don’t have any of the concerns that you do with running pistol gas on 5.56.
I don’t think I personally would ever build a 300 with anything BUT a pistol gas system. YMMV

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With a 10.3" barrel obviously I have pistol length gas. I’m just missing some velocity I’d get with a longer barrel. Every firearm has tradeoffs.

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