Anyone accidentally used 300 blkout in 556?

[RVTMaverick]

Hey Ned.,
I have that mag., and ofcourse read your article, great write up by the way, plus the pictures, the picture of the Super elongated .300BO with the barrel cut in half was AWESOME!

I did an article in one of the Guns & Ammo AR15 specials-- the 6/25/2019 edition. Yep it blowed up alright. Bullet stuck in the barrel; it got reeeaall long.

[RHINOWSO]

300BLK has a viable role - but for my wants & needs, the risk of this KABOOM happening hasn't been outweighed by the benefits yet.

So I just deal with a louder shot from a 5.56 / 762x51 or decreased terminal performance from a 9MM PCC.

[WillBrink]

300BLK has a viable role - but for my wants & needs, the risk of this KABOOM happening hasn't been outweighed by the benefits yet.

So I just deal with a louder shot from a 5.56 / 762x51 or decreased terminal performance from a 9MM PCC.

I don't really see myself ever owning anything where it's that easy to mistake one rnd for another and see kaboom or worse. Risk to benefit simply not there and I doubt it ever will be, at last for me.

[themonk]

I really dont see this as an issue. Keep everything separate and come up with a system to manage the risk.

[mack7.62]

That was the whole point about the Lancer mag comment, it doesn't have to be Lancer's but best to pick one brand of mag's for .300 and a different brand for 5.56. The Lancer mags have some advantages for 300, they work well, look and feel different and if you stick with the translucent they are another indicator that they are for .300 use only.

[WillBrink]

I really dont see this as an issue. Keep everything separate and come up with a system to manage the risk.

I suspect those who had their rifles go boom were aware of that too, but chit happens. That being said, the Q is, is the risk/benefit there to justify owing them both? For me, answer is no as the 300 offers me little or nothing I can't get from either the 5.56 or 7.62. For others, there may be compelling enough reason the 300 fits a niche they want filled not filled by the others, and benefit exceeds risks for them. Your millage may vary. Like a lot of things, it's not an issue until it's an issue...

[Pappabear]

I wouldn’t think the bullet would chamber and it would malf before going off, hmmm

I, in my infinite brilliance stuck my 556 can on 762 gun. Mark started the string off with sub Sonics and we both thought, got fkd by the unstable subs. It was later in the day until I figured it out. AAC said, if the can isn’t ballooned or warped, we can fix it. Luckily the low velocity bullet just blew the cap off. AAC completely redid my can , so lucky.

I had a friend at LGS did same thing , same cans but full power ammo. “Sorry sir your out of luck”. And he was the owner of the store that sold AAC.

The new cans and adapters prevent this non sense. Old AAC did it so you could run your 762 on your 556 which is cool but NOT vice versa.

I was taking a pistol class once upon a time and a .40 got mixed up with my .45. Shooting 1911’s. I just happen to load it when the class was competeting in one of two competitions, it cost me. I picked the spent round up only to allow that same round back in my gun during the second competition of the class. I don’t own .40 anymore. Shitt happens when you shoot a lot. Sooner or later. Shoot once a month or a qtr and your attention to detail jumps IMHO.

Like Will, I’ve never seen anything wonderful that my 556 762 mp5 with subs won’t get done. As always YMMV.

PB

[fedupflyer]

In my experience, Lancer mags do not run very well with 300 BO.
You might shot for a while before they begin to double feed but they do not cut the mustard for a competition mag. If they won't run reliably in competition then they are not suitable for home defense.
So far, they only mage that I have found that run reliably are the Magpul 300 BO mags.

[TXBK]

300 Blackout is why they make Lancer mags.

When I had the BO, I used Lancer mags for this very reason.

300 BO only loaded in Lancer mags. Lancer mags only in 300 BO rifles. I keep ammo in its box, loose ammo drives me nuts, and only mass load one caliber at a time into magazines. It’s simple and effective.

[TXBK]

double tap