How to prevent a 300BLK round being fired in a 5.56 upper ?

Discussion about rifles in 300 AAC BLACKOUT (7.62x35mm), hosted by the creator of the cartridge.

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mostholycerebus
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Re: How to prevent a 300BLK round being fired in a 5.56 uppe

Post by mostholycerebus »

Etched dust covers are my first line of defense. They clearly state "300 BLK" or "5.56", on both sides so you see it when open or closed. They are right where a good gun owner will look when doing a chamber check when they pick up the rifle. If a $10 dust cover will save my $1000 rifle, or priceless hands/face, just once, thats a good investment.

Next is color coding. All my 300BLK rifles are...black. Black = Blackout, get it? All my 5.56 rifles have OD, or FDE or pink furniture.

Next, magazines. Im using Lancers for 300BLK, pMags for 5.56. Originally, I went this way because Lancers just worked better with 300BLK, but the differentiation helps.

Last, magazine markings, or the rubber loops like sold in the marketplace, make it pretty apparent which is which. I dont have these yet, but if I was sharing rifles with non-family (not familiar with my system) I would add them.
Notar
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Re: How to prevent a 300BLK round being fired in a 5.56 uppe

Post by Notar »

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http://www.bradswarehouse.com/

I like the Lancers Too!!!!!

The Bands are just a Band-aid to the problem though. I've tested many loads with a pretty heavy Lee Factory crimp die, and chambering 300BLK rounds from a locked back bolt in a 5.56 cause setback. The Blacktip load is the best resistor to setback!!
Schuyshot
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Re: How to prevent a 300BLK round being fired in a 5.56 uppe

Post by Schuyshot »

WhoDatRR wrote:Just found out that my 300aac won't chamber 6.8 rounds, this weekend. And thank god it doesn't!

That'll teach me to not throw different caliber rounds, in the same reload boxes.

Yep happened last summer to me. 6.8 didn't perform in my 556 chamber... :oops: luckily!
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Re: How to prevent a 300BLK round being fired in a 5.56 uppe

Post by Schuyshot »

Etchings or livestrong bracelets are not going to prevent a 556 from finding its way into a mag of 300 or versa... If you push the wrong load into the mag its likely going into the chamber (or at least trying)

Take a page from FM 4-30-13

Figure F-6 to be exact!


I think the best way to prevent mixups is to mark each bullet.

Give a tray of projos a blast of black paint or whatever color before loading.

Or a brush across the top of the box of ammo before you call it quits at the bench.
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Dolomite_Supafly
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Re: How to prevent a 300BLK round being fired in a 5.56 uppe

Post by Dolomite_Supafly »

TCustoms wrote:
gds wrote:
TCustoms wrote:First off, you're NOT going to blow it up if you do. Ruin your chamber ? Probably so.

Pay attention to what you're doing is as easy as it gets.

Oh no it will blow up the gun. Nough people have done it to prove that.

My fix for it is to only shoot subs. :mrgreen: they wint even come close to chambering.

Seriously, it is simply something one has to be aware of when using shorter rounds. They projectile can get set back enough to allow for the bolt to fully close. Marking the magazines is a good way. Some people will designate a specific magazine type for 300 blk.
My definition of "Blows up my gun" must be very different
This is what happens:
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I would consider that "blown up" by anyone's standards.

It is a GRENADE and will ruin the gun among other things.
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Dolomite_Supafly
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Re: How to prevent a 300BLK round being fired in a 5.56 uppe

Post by Dolomite_Supafly »

And here is another gun I would consider "blown up"
First of all, no one was hurt with the exception of his pride. And no, it wasn't me.

A Blackout owner mistakenly...**** it...stupidly chambered the 300 in his brand new DD 5.56 upper. It was the top round in the mag and when he released the bolt, it went forward and jammed the head back into the case. When he pulled the trigger....

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VENT625
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Re: How to prevent a 300BLK round being fired in a 5.56 uppe

Post by VENT625 »

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"Trust me...I know what I'm doing."

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tfbit
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Re: How to prevent a 300BLK round being fired in a 5.56 uppe

Post by tfbit »

"Tis but a flesh wound..."
No matter what you read on the intarweb CCI450s and CCI41s ARE NOT BALLISTICALLY IDENTICAL with H110! I'm also not a intarweb lawyer so I don't argue with anyone who is.
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gds
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Re: How to prevent a 300BLK round being fired in a 5.56 uppe

Post by gds »

DS beat me to it.

I actually did not think one could even chamber and said so in a thread on here I think. but then I got curious and went out and made a dummy round with a short projectile and after loading it twice, the bolt did in fact close all the way. I had teat crow on that one big time.
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Re: How to prevent a 300BLK round being fired in a 5.56 uppe

Post by 20X11 »

TCustoms wrote:First off, you're NOT going to blow it up if you do. Ruin your chamber ? Probably so.

Pay attention to what you're doing is as easy as it gets.
YES...It does blow up the gun...think grenade...search this forum for Kaboom for pics.
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