AAC 5.56 Ammo Evaluation

[SuperJLarge]

This dog shit continues to shred my nutsack. After reworking hundreds of rounds to a thoroughly tested charge, we got a few FTEs in a know good gun.

Busted out the chrono and got 2828 fps (on the same 20" Bolt gun) on a load was developed to shoot about 100 fps slower than that.

At this point, due to the horrible velocity swings and shitty SDs, I'm suspecting the mongoloids who make this shit mixed powders of various lots/burn rates.

2828fps isn’t exactly screaming for a 20” bolt gun. I’ve had 2811fps averages from an 18” AR running IMI Razorcore.

That same load that you listed should be around 2760-2775fps in an 18” AR.

If I’m reading your post correctly, these were loads that you had reworked so it’s not factory loaded ammo, correct? During reloading of the ammo, did you notice any differences in kernels/color or does it look to be the same brand/type of powder?

Since I’ve still got several boxes of the same lot you’re using, I’ll try to break down some myself if you don’t have any left.

Would like to help as much as possible, but I haven’t had any issues with that same lot #. I ran it this past weekend in a Daniel Defense 16” and a KAC 11.5” with zero issues. I do have a few additional 10.5, 11.5 and 12.5” uppers that I haven’t shot this in yet. I’ll try to run them soon to see if I get similar results. I think 2 of them are 5.56 chambers, with 1 being a 223 Wylde.

[markm]

2828fps isn’t exactly screaming for a 20” bolt gun. I’ve had 2811fps averages from an 18” AR running IMI Razorcore.

We use the same 20" bolt gun for every load test so there's good reference. 2828 is just part of the story. The other piece that I can't measure is pressure curve. 2828 with a nice slow powder might work, but 2828 with whatever these booger eaters used is most certainly NOT working.

As far as visual on the propellant, I can't look at TAC, for example, and tell it from H335. And those have to pretty different burn rates in a 223. The only thing I did see that was curious was posted earlier in this thread. The sticky, clumped powder in every 50th or 100th round.

[bfoosh006]

I don't recall, what chronograph are you guys using ?

And how firm of a crimp did you apply ?

I am also curious about who supplied the propellant... and its burn rate.

FWIW, I have some AAC 77gr Sierra TMK on the way.

[markm]

I don't recall, what chronograph are you guys using ?

Magnetospeed.

Add: Light Factory Crimp. The messed up thing is I shot this 5 round group. 3 in one hole and the 2 by it for like .3 MOA.... with a 26 Standard Deviation!

[bfoosh006]

Magnetospeed.

Oops... I added to my post.

[MidwestExpress]

Had 12 primers blown out in 100 rounds, Ejector indent marks similar to those seen on a previous post. Threw the rest away.
Brand new Criterion hybrid, 14.5", .223W chamber.
Running a Dead air sandman K on the end.

IMG_2792 (1).jpg

[Hush]

Picked up 500 rounds of AAC 77 gr OTM from palmetto last month and shot half. No issues with failure to fire or extract, Chrono showed consistent velocities over a sample of rounds from each box. Cases were clean and undented, better than pics I've seen online from other lots. Gun was a 14.5 factory BCM upper.

Sent from my SM-A326U using Tapatalk

[markm]

I can't believe there's not been a Kaboom with this crap.

[SuperJLarge]

Had 12 primers blown out in 100 rounds, Ejector indent marks similar to those seen on a previous post. Threw the rest away.
Brand new Criterion hybrid, 14.5", .223W chamber.
Running a Dead air sandman K on the end.

IMG_2792 (1).jpg

What lot #?


Welcome to the site!

[MarshallDodge]

I see MidwestExpress is running a 223W chamber and is having issue. Hush is running a BCM which I would assume has a true 5.56 chamber.

Are the others that are having issues using a 5.56 chamber?