Hornady Black (90001) 40gr Vmax

[Buffman]

Hornady is sending me 6 boxes of the Black as as well as the Critical Defense. I bought the 250 rounds for this testing from Patreon funds before I was able to get in contact with Hornady. They are using their own brass. The brass is on average 56gr vs the 60gr FN. It holds about 12.8gr of water vs 12.0-12.2 that I got from the FN.

5.4gr powder charge, and we are meeting the BOX state velocities. On the same day we are seeing 170 fps improvement over SS197SR. Penetrations depths on the pistol and pdw barrels are above the FBI Min. It is not a bonded bullet, so keep that in mind.

The bad news 4 case neck separations. 3 in the MK57, which because of the RDB and nature of the BCG saved itself from exploding. However the AR57 upper I have does not have any OOB provisions, and the second round fed on top of the broken case neck, and subsequently KB! the gun. It held up very well and I have no injuries, but it's down for the count. AR57-Center is replacing the upper and they mentioned starting mid last year they have made changes to it's BCG to help prevent OOB firing.

We've had case neck separations in the FN brass before so this is NOT uncommon. We will need more rounds down range

https://youtu.be/tshdtGCl5Aw

[panzermk2]

Man their brass.

[towerofpower93]

Hornady is sending me 6 boxes of the Black as as well as the Critical Defense. I bought the 250 rounds for this testing from Patreon funds before I was able to get in contact with Hornady. They are using their own brass. The brass is on average 56gr vs the 60gr FN. It holds about 12.8gr of water vs 12.0-12.2 that I got from the FN.

5.4gr powder charge, and we are meeting the BOX state velocities. On the same day we are seeing 170 fps improvement over SS197SR. Penetrations depths on the pistol and pdw barrels are above the FBI Min. It is not a bonded bullet, so keep that in mind.

The bad news 4 case neck separations. 3 in the MK57, which because of the RDB and nature of the BCG saved itself from exploding. However the AR57 upper I have does not have any OOB provisions, and the second round fed on top of the broken case neck, and subsequently KB! the gun. It held up very well and I have no injuries, but it's down for the count. AR57-Center is replacing the upper and they mentioned starting mid last year they have made changes to it's BCG to help prevent OOB firing.

We've had case neck separations in the FN brass before so this is NOT uncommon. We will need more rounds down range

https://youtu.be/tshdtGCl5Aw

So, the separated case neck stayed in the chamber and the next round fed in, causing the round to be OOB but still allowed the gun to fire? I've never seen an AR57 upper or bolt, but I would have thought they'd stick with the AR carrier design which blocks the hammer from hitting the firing pin unless the bolt is in battery.

Glad to see you weren't injured.

[Buffman]

Yep, this bolt design in mine still allowed it to happen.

[panzermk2]

To be fair, shooting through a piece of neck is not new for the 5.7 platform. As Matt states it happened to some of the other guns during this test also. It just didn't blow them up.

Had it been one of the pistols like the FsN it would have blown the mag out.

[panzermk2]

I will find the link to a very old thread talking about this, and what you can look for if you are a reloader to avoid using a case that is close to failing.

[panzermk2]

https://www.fivesevenforum.com/viewtopi ... 19&t=16756