Home Forums Hunting & Shooting AR and Tactical Rifles Had a "boom" yesterday

Known good rifle.

Blew the magazine out the bottom, blew the mag bottom off. Bolt hard stuck, case is still in there. See pictures.

223 rifle shooting reloads with 55 Hornady SP over 24.7 grains of TAC. Range brass (which might be the problem?), CCI 450s

Barrel does not seem bulged (as in obstruction), and it would be hard to fit too much TAC in a 223 case, especially under a 55 grain bullet.

Barreled upper is sitting at the 'smith's now waiting for him to have a look.

Thoughts on cause? Thoughts on breaking the rifle down to do forensics?

I run 27 grains of TAC with a 55 grain bullet, no way to get too much powder without noticing.

I figure case is at fault. Probably separated.

Separated case or previous round had 0.0 grains of TAC? Glad you’re ok.

It was the first shot in that series, so I doubt a misfire or barrel blockage.

But, I'm getting the habit of checking the bore prior to shooting from now on.

Range brass is my first thought. Coupla years ago a notorious scrounger at my IWLA range totaled his upper with a reloaded pickup case. He even fessed up about the likely cause.

Schitt happens, but happens less to the prudent. Let us know what he says.

Glad you were not injured. Hardware can be replaced.

I had two pieces of range brass split upon firing a couple of years ago, but I never even knew there was a problem until I examined the brass later. It fired and ejected fine. I guess I got lucky.

Range brass is perfectly fine, if you know what you are picking up. Some is garbage and just stays in the dirt. The last time I picked up any, it was primo new once fired chidt. FC and PMC. That was a few years ago and that's mostly all I've been using since then. I think I picked up 1200 pcs of FC and 600 pcs of PMC. I made it a point to shoot the FC range pick up brass in the black rifle challenge here. If you don't know what you are picking up, leave it lay. Sometimes there's a reason it's laying there. Secondly, I'm wondering if the rifle fired out of battery? Glad to hear no one was hurt as well.

I'd also suspect an out of battery ignition.
I've had two case separations involving range brass over the years, neither caused any damage.
I didn't even know anything was wrong until the front half of the case didn't eject.
If everything is contained in a locked chamber that shouldn't have happened.

Firing pin won’t reach the primer until bolt turns and locks into receiver extension.

That is taking his word that it was a known good gun. Also assuming it wasn’t a high primer. David just doesn’t seem like the guy that would miss that.

Also going by all the ka-booms I’ve kept up with over the years they mostly have been ammo related.

Also gonna say this again, FC is the last brass I’ll ever pick up and it’s the only brass I’ve lost primers in.

Brass laying on the ground needs to be checked for signs of separation no matter the head stamp.

We’re reloaders and range brass is free but the prep isn’t.

Hang fire?

I've had 2 case head separations, in bolt rifles. I didn't know it until I extracted only the back end of the case. Not sure if being in an AR makes a difference or not.

I'm curious to hear what the smith finds.

Glad you walked away unscathed, David

Just a possibility,

Oncce upon a time I was trying to call coyotes. No luck and no luck and no luck.

After about 6 stands, unloading and loading every time with an ar-15, same shell every time, The last time I unloaded I found the bullet setback into the case enough that the bullet ogive was almost into the case shoulder, almost rattling in the case.

I never shot that one but often thought that it could have been a catastrophic event. No way we'll ever know but it would have been hard to diagnose for me.

Now I crimp my 223 better.

I've seen split cases, separated cases, blown primers and set back bullets in AR platforms. Only time I ever saw any damage similar to this was from a slam fire / out of battery condition (not counting the pictures of the 300 BO fired in a 5.56 chambered rifle).

I'm trying to figure out how you can get a slam fire/out of battery when the firing pin can't reach the primer until the bolt rotates and locks into the lugs of the RE?

A bullet setback could cause the bolt to unlock and force the gas/pressure out the easiest route but an OOB firing is next to impossible unless the firing pin is out of spec or broken.

Slam fires have occurred but never resulting in a blown up AR like this.

Not trying to argue just simply going over facts trying to determine what happened.

He was using FC brass?

You can try to figure it out all you want. Over the years, we've all probably had split cases. Never having it fu ck up the gun like this. Something was not right with the load or rifle. A lot of speculation on your end though.. The one sure thing you said is we all need to be very aware of the brass we pick up. Like I said, if its garbage brass, don't pick it up. I find all kinds of military crap brass and leave it lay. I've walked over tons of it. Check out some of the recent manufacture WW brass that they load for the military. Its garbage. The FC I picked up has scamp markings on it, but its commercial brass. Its much better than regular ol FC brass.

Not knowing all the facts, it could have been a high primer that detonated on the closing of the bolt, if there was an obstruction it would have to be past the gas ports otherwise the barrel would have burst since the rotarary bolt would or should have been totally engaged

most people like me, leave bad brass on the range for people that are scavengers for brass to sell for scrap. I only use my brass and in 50 years of reloading never had a problem, or blew up a firearm... you pick up junk and your reloads are junk, stop that ....