Need Help On This

[3up]

Anyone ever see this happen before? Once fired 5.56 brass reloads. Shot from one of my AR-15 rifles. All steps were followed for reloading 5.56 brass. As you can see from the picture part of the primer is still on the pocket hole, but the back of the primer completely blew out. Anybody have any idea of what happened here?

.224 55gr
556 brass
21.5gr RE 7
CCI primers
LEE Measuring cups this time. Usually it’s an RCBS 1500 chargemaster

[pacrat]

Welcome to CalGuns

Anyone ever see this happen before?

Yes.

Anybody have any idea of what happened here?

Just guesses without further input. Maybe, even after further input.

Sometimes crap happens, especially if isolated incident, without ever discovering a specific causation. In which case it's chalked up to Murphy.

possibilities Faulty primer cup. Oversize flash hole. Overcharge

Did something draw your attention when fired. Louder, more recoil, smoke from ejection port, etc, etc.? Or found on ground during cleanup, and notice primer?

Flash hole diameter?

Will 43 gr of RE-7 fit in 5.56 case? With "dipper/funnel/loading block" it's easy to lose track. Over charges will blow primers. But if you overflowed the case. You'd know it immediately.

[tabascoz28]

Picture isn't close enough to see primer hole. Could have been loose primer already. Over decrimp process? Was 21.5 max in the books? Did you have a 62 grain tip mixed in with 55 grain or something of that nature?

[3up]

Picture isn't close enough to see primer hole. Could have been loose primer already. Over decrimp process? Was 21.5 max in the books? Did you have a 62 grain tip mixed in with 55 grain or something of that nature?

If I remember correctly 21.5 was somewhere right in the middle or below that. No this was a fresh bag of 55 grain

['ol shooter]

My guess is that the primer was forced into the pocket and fractured the cup when it was installed. You can answer that one by telling us how hard it was to insert it when you loaded them. I use a primer pocket gage to set my swager so it is done correctly, do you?

[baih777]

Are you using a standard small rifle primer or the military small rifle primer ?

Where did you get your load data from ?
On the alliant site. It does not list 55gr.
Did you work up this load ? Or are you just loading from a book ?

Looks like just a blown primer from too hot of load.

[Donny1]

Is this a clue maybe?

[ar15barrels]

Will 43 gr of RE-7 fit in 5.56 case?

43gr of RL7 will occupy about 180% of the available space under a 55gr FMJ-BT bullets in a 223 case.

[pacrat]

43gr of RL7 will occupy about 180% of the available space under a 55gr FMJ-BT bullets in a 223 case.

Well he can scratch that off the list.

[3up]

43gr of RL7 will occupy about 180% of the available space under a 55gr FMJ-BT bullets in a 223 case.

It was 21.5gr RE7, not 43gr of RL7

[ar15barrels]

It was 21.5gr RE7, not 43gr of RL7

We were ruling out a double charge.

[ar15barrels]

LEE Measuring cups this time.

How many charges did you weigh from the lee cups on an actual scale before reloading?
What weights were you getting on the test drops?

[divingin]

My guess is that the primer was forced into the pocket and fractured the cup when it was installed.

Never seen a primer cup fracture. They're sheet brass stamped into shape, and from what I've seen, they'll bend, fold, and otherwise mangle up, but I doubt they'll fracture.

They may blow the flat out when firing (pretty rare, and takes really odd circumstances) or tear out the flat when decapping, but that's post firing.

[BrassCase]

Isn't RE7 a bit fast for a 55 gr. 223?

[ar15barrels]

Isn't RE7 a bit fast for a 55 gr. 223?

Yes, but its not horrible.
There are 14 powders that will give more velocity at the pressure he is at so you are not likely to see it recommended much.