stretched out 300 black out

[delftshooter]

I am just curious as to why the 300 black out has such a short case. Wouldnt it be easier to juse use the original 223 case length of 1.76" and simply neck it down to take .308 slugs?

Wouldnt that then allow it to become the youthful 30-30 semi automatic clone that companies have tried to make several times in the last 120 years?

[Plate plinker]

The original projectile would not allow the cartridge to be chambered in a .223 chamber. I was told this by a person who was involved in the development of the 300 BO. I had voiced the same concerns.

[Rapier]

The 300 BO is a copy (minor changes and a whole different subject) of the 300 Whisper designed by JD Jones for the Seals and is /was based on the 221 case and not the 223 case at all. A 223 case can be used to make a 221x30 another name. The request of the Seals was to have a M-4 round for subsonic social work that only required a barrel change and changing nothing else. The bullet selection for the Seals goes from 200 grains up to a 400 grain RN all copper job that uses body armor as part of the projectile. Like a 1,000 fps arrow.

So you must fit everything into an AR-15 223/5.56 mag and it's length to achieve the original intent as established by the Seals.

My standard load is a 230gr hard cast, 7,2,1 alloy water dropped, plain base, powder coated sized to groove, over H-110 for 900 fps that shoots 1/2" at 50 yards. It is a JD Jones internet published load. JD was an IHMSA match director and owner of SSK Industries. A whole line of cartridges bear his moniker of JDJ.

[Hdskip]

The .223 has been necked up to .30 cal. With most bullets it doesnt feed well in AR platform. It is however a lot of fun in a bolt gun.... There is something in between called .30 HAMR. I have no experience with it though. Maybe others can chime in.

[Nobade]

I have a Rem 700 chambered for 30-223 AI. Pretty much a 30 TCU, same same. It's in a chassis stock and uses AR magazines. Heavy bullets do need to be seated really deep to fit in the magazine, but with 150 gr and lighter it really rips. Almost does what a 30-30 will. I built that years ago just because of the unlimited free brass I could pick up at the range. But the question has already been answered, it's really too long to work very well through an AR platform rifle.

[delftshooter]

everyone knows the only worth while semi automatics are chambered in 308, 30-06 and 8x57..

this would be in a bolt gun. Have seen the .223 blown out to use 8mm bullets. But the 30-30 idea would sell alot of guns

[longbow]

First time I saw it it was in an article by Roy Dunlap in the Gun Digest 1986 and called the .30 Apache. As noted above also know as .30 TCU or .30/.223. There may be some minor differences but basically the same cartridge.

It does give about .30-30 Win. performance but with more ballistically efficient pointed bullets. It should be a good cast bullet round too.

Merry Christmas all!

Longbow

[BK7saum]

One issue with many bullets in the cartridges longer than 300 BLK is the nose length of the bullets.

I have a 300 hamr and 300 BLK. There are only a handful of bullets that work in the Hamr and even less that would fit the 30-223 in an AR.

For a bolt gun with longer magazine options, this is not much of an issue, but options are limited with the longer cases in the AR platform.

[longbow]

I should have said that Roy Dunlap was using a bolt action gun. Also, I have an article by Elgin Gates using .30-.223 but in a Thompson Center Contender. In both cases bullet length wasn't an issue for them. Roy Dunlap loaded bullet weights up to 190 gr. and down to 125 gr.

Longbow

[D.Bullets]

Merry Christmas everyone.
I have a AR Platform in 300 BLK with 2 uppers and 2 buffers along with the 5.56 upper. (One for high Vel) and the (second upper for sub w/silencer) and the 5.56. Switching is easy and unmistakable as its intent. Both 300 combo's work extremely well. Before I was forced to destroy my bump stock either setup would empty a 20 mag in seconds, but not much fun, for me anyway.
I found A1680 to be a must in the Subs preformance.
I would also like to add that there is a plethora of Boolits to choose from, athough I cast my own. I would like to get a 300 in bolt action.

[Texas by God]

The length of the AR15 magazine is the reason that cartridges that fit it are doomed to always be “almost”something else.
A .22 Nosler is almost a 22-250.
A 6.5 Grendel is almost a .250 Savage.
A .30 Hamr is almost a 30-30.
And so on.


Sent from my iPhone using Tapatalk

[popper]

A 300 Hamr is almost a 30/30 for the chosen weight of bullet the Hamr can accommodate. Same with the 40WT. 300 BO accepts MANY bullets and performance is good for all. 223 cases are difficult to 'stretch' out without some care, BO is easy, Hamr is tougher.

[Baltimoreed]

Been messing with a 300Hamr too but to get it to run my mini/garand build.

[Nobade]

That's cool!

[rockrat]

Got a barrel from Northland chambered in 300 BLK and eventually ran a 30 Apache reamer in. Used 300 BLK dies to load. Then I pulled the barrel off and ran the 30 Apache reamer in .090" deeper and use 204 Ruger brass. Will try boolits next year and see what it does. All used in a single shot action

[lar45]

Wasn't there a cartridge made by running the 300 Blackout reamer in deeper to make something similar to the 300 Hammer but load with 300 BLKout dies? I can't remember the name, 300 American or something???
If you want to run subs, then the 300 BLK makes alot of sense, otherwise the 300 Hammer sounds better for lighter bullets and higher velocities.
I went with the 7.62x39 in an AR Pistol.

[popper]

There is the 40WT, forerunner of the Hamr. Wilson extended the case and neck for the Hamr.

[Bmi48219]

What, if any cartridges are formed from a 300 BO case? Preferably something of larger diameter that could be run through an AR with just a barrel change.

[jdgabbard]

The one thing I didn't see mentioned is, the 300 Blk was purpose designed to shoot HEAVIES... Seriously, it wasn't designed to be a 30-30, it was designed to be a capable combat rifle cartridge with subsonic ammunition. By that very definition it wasn't ever intended to be anything like the 30-30 but for in diameter of the bullet.

[Randy Bohannon]

This ^^^^^^^^

The military was wanting a rifle for suppressing in 30 cal. they tried fast twist 1:7 barrels on the 308 Win. and Trail Boss powder and even seating 220 gr. SMK’s backwards. They weren’t happy with getting sound below their threshold. Advanced Armenant was given a contract to develop a cartridge that would achieve their criteria. A.A. was aware of the 300 Whisper and changed it enough to avoid proprietary royalties.The purpose of the rifle was for Special Forces to take out sentries on guard without detection and had to work in the M16 platform at 200 yds. They achieved that goal with aplomb.
Remington was involved with the 308 Win. tests and made about 400 1:7 Mdl 700’s with 16.5” fluted barrels after the test they sold the rifles to dealers,I have one of those rifles.