Thread: 300 Blackout Fired In 223

.300 Blackout Fired in .223 Rem — Mistake Is Disasterous « Daily Bulletin

That 308 projectile at the bottom is amazing!
Would never have thought it could extrude so nicely into a 5.56 bore.

I remember talking to a guy that fired a 308 in his 2506....split the reciever open like a banana skin, blew out mag well and siezed the bolt in place.....bloody lucky he didnt get hurt

Nasty stuff, my brother gave a guy a 7x57 round for his cartridge collection at a range shoot and some how this guy chambered and shot it in his 270. The rifle held together but booted the hell out of him, the diameters are close at .284 and. 277 but that's sure playing with fire.

There are actually quite a few cartridges where cross chambering is possible that's a valuable reminder.

Good to know. I wouldn't have thought it possible. Everyday is a learning day. Luckily, I don't own a .223. Some of the comments are mildly amusing.

Is it possible to fire .223 through blk barrell? I assume it will not chamber fully?

Originally Posted by zimmer

.300 Blackout Fired in .223 Rem — Mistake Is Disasterous « Daily Bulletin

Greetings Zimmer,
In the US they generally try not to have miss matches like that. The .280 Rem and 7mm WSM were both given longer headspace to stop them being chambered in the .270 Win and .270 WSM respectively. I suppose the .300 Blackout initially being a proprietary cartridge it may have missed that step. Just shows you can't be too careful and we should be careful with our calibre selections and especially reforming brass from one calibre to another. I prefer to make 6.5-06 brass from .26-06 cases partly for that reason.
Regards Grandpamac.

only some blackout loads will chamber.depends on the projectile.always thought in combat dropping weapon as running away with couple of 5.56 loads on top and blackout under would be cunning ploy....
there has been morethan one 308 fired through 270 before....not recomended.

Originally Posted by veitnamcam

That 308 projectile at the bottom is amazing!
Would never have thought it could extrude so nicely into a 5.56 bore.

the legendary squeeze bore! Wounder what the BC of that would be.

But unfortunately yes 300 will fit in 223, not the other way round.

We managed to fire some 308 out of 7.26x54R, tied to a tree with a string to pull the trigger. Worked well.

Greetings All,
A mistake made in the US in post war years was firing an armor piercing 7.92mm German round in a .30-06. Last shot for the rifle and not all that good for the hunter either.
Regards Grandpamac.

Greetings All,
There were also stories about a 6.5 mm Arisaka being rechambered for the .30-06 after WW2. The owner hunted with it and shot a few deer with it but the recoil was major. He took it to a gunsmith who discovered the problem. He was using standard .30-06 rounds and the pill was being swaged down to 6.5 in the barrel. I believe that this was written up in the NRA Journal at the time. Amazingly the action took the beating but not the hunters shoulder.
Regards Grandpamac.

I can relate to this comment, Get people not knowing enough about cast bullets asking all sort of stupid questions that the answer is quite obvious if they thought about it.

“Had some dude come into the store the other day wanting .300 Blackout ammo to shoot in his 5.56 AR. It took 15 minutes of explaining for him to understand you got to have a .300 Blackout Upper!” — R. Williams

I know of a Thompson encore .223 that had a .222 round accidentally fired through it out of a new box of shop bought .223 ammo. Needless to say the shop/ammo manufacturer swiftly replaced the heavily damaged rifle with minimal fuss! Incredible the forces present in such a small cartridge.

Originally Posted by Hayden

I know of a Thompson encore .223 that had a .222 round accidentally fired through it out of a new box of shop bought .223 ammo. Needless to say the shop/ammo manufacturer swiftly replaced the heavily damaged rifle with minimal fuss! Incredible the forces present in such a small cartridge.

interesting that it would cause a lot of damage....guess the delayed pressure spike was the culprit...sort of fireforming a case forming on grand scale