Sunday, December 04, 2016

Why, if you have a .223 and a .300 Blackout, you'd better make sure

you don't get the wrong rifle & cartridge together

Some students who made false rape reports being prosecuted.

Good.  Every time some idiot does this it both takes LE resources away from real crime reports, and can destroy the life of the falsely accused.

Oh, this is wonderful, they couldn't even make sure the jeep for the FUNERAL would keep running?

Well, 'liberals' are cheering the fires in Tennessee, so I guess they'll say the old lady deserved being hit with a chair, because Trump! or something.

Government-run health care...
Four staff members have resigned from a southeastern Oklahoma veterans facility rather than face the possibility of getting fired, after a resident was found to have maggots in a wound.

Oklahoma Department of Veterans Affairs executive director Myles Deering said the maggots were discovered while the patient was alive at the facility in Talahina, about 130 miles southeast of Tulsa. Deering said the maggots were not the cause of his death.
The agency said a physician's assistant and three nurses, including the director of nursing, resigned after an investigation was conducted. Spokesman Shane Faulkner said all four chose to resign before the termination process began.
I refuse to comment on this, as my language is deteriorating into cursing before I even start typing.


taminator013 said...

Yikes! I didn't realize that a .300 Blackout would completely chamber in the .223 barrel. That would get really ugly for the shooter and anyone nearby....

Arthur said...

My boss has a sideline business in laser engraving and he burned 300BLK in BIG letters into both sides of my friend's AR15 dustcover as an easy visual reference.

My friend also has the mags he uses for BLK marked in big neon letters to match.

We were looking at that whole kaboom issue when he first got it and were kind of surprised they hadn't managed to design the round to prevent chambering in a 223. For instance, the 460 Rowland they made the case slightly longer so that even with the same OAL as 45acp it shouldn't chamber in the .45 gun.

Firehand said...

It will, and it has. Big kaboom. Here's one

Same thing Arthur mentions, I've read of a bunch of people specifically marking magazines and ONLY using that round in them as a safety measure.

genericviews said...

That's why I keep a limited number of calibers in my arsenal. I don't like to get them mixed up.

taminator013 said...

I read the article at the link. That guy was very lucky not to be injured. Too bad that his nice, new shooter didn't fair so well........

markm said...

Here is a picture of three .300BLK rounds alongside a 5.56mm and a 7.62x39mm.

It looks like the designers started with a 5.56 case and cut the neckdown off so they could stuff in a larger bullet. They added a slight neckdown to the shorter case, which I assume is where the round headspaces in a .300BLK chamber, and which will positively prevent jamming a 5.56 into that chamber.

The other way around, it might depend on how far back the bullet taper begins, but it looks to me like all three .300 bullets will hit the 5.56 headspace before the bolt closes. So to get the 5.56 gun into battery, the bullet has to be pushed into the case past the cannelure. But sometimes that doesn't take much force, and the AR-15 return spring is pretty strong.

I think The best fix is to start over and design a whole new round, either with a case that is wider so it won't chamber at all in a 5.56, or longer so the case extends past where the 5.56 headspaces and it cannot be forced into battery. Possibly .300BLK rifles could be converted to the new cartridge by reaming the chamber.

The other option is to switch to a weaker powder or add filler so a properly filled case has no space left behind the bullet. I'm no expert, but it seems to me that for this to work, the powder would have to be pressed into the case so it could not compress any further when the bullet was pressed back. It would also require exceptionally tight process control so there was never just a little gap left. Factory ammo would cost more, and handloaders would have to be extra careful.

Gregg said...

My solution is to use only Pmags in my 223/5.56 ARs and only metal mags in my 300BLK ARs. Gives me both a visual and tactile reference.

Oh, and DON'T take both calibers to the range if you have new shooters along. They can be introduced at different range sessions.

Firehand said...

Gregg, I've seen exactly that method from a number of people. Plus some write '300' or '223' on the side of the mags in some bright color.

Markm, my understanding is that's exactly how they made it, and a lot of people do cut down .223 or 5.56 brass and neck it down to make their cases. Someone wanted ballistics more like 7.62x39 in a case that would work with standard .223/5.56 bolts and magazines. Also, using heavy bullets(it'll work with some up to 220 grains) and subsonic loading it works very well with a suppressor.