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[ARCHIVED THREAD] - Frontier 55 grain boom and damaged extractor. *update Hornady says pound sand (Page 1 of 5)
Posted: 6/17/2019 3:41:05 PM EDT
The application is a Colt 6921 Diemaco upper and 6920 lower. This rifle has approximately 3800 rounds through it, not one malfunction. Yesterday I was shooting frontier 55 gr When suddenly there was a boom and the bolt carrier did not fully seat back in battery. Despite this I had to mortar the rifle to unlock the bolt back as the cartridge was stuck in the chamber. I immediately could see that the case had been ruptured on the right hand side. I used an AK cleaning rod to remove the stuck cartridge. I was not aware until I did some searching afterwards that some people are having similar issues with this ammo. I am currently in the process of contacting Hornady , but initially one of the representatives has said to me that it would be possible for this to happen if the rifle had been fired out of battery. My question is how can an AR15 physically be fired with a cartridge out of battery unless the primer was not seated properly and was protruding from the cartridge more than usual? Secondly is it likely that Hornady can replace the damaged bolt or extractor or am I shit out of luck? I'm grateful nothing else was damaged and I did already try to fire the rifle again with a different type of ammunition and another Colt bolt Carrier group. Everything seems to be working fine but I am a little aggravated that this has happened and I do believe that Hornady should replace my bolt assembly. Thoughts?
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Ah yes, good old Frontier ammo. Soooo glad I never bought any of that. As to OOB, no. OOB would mean unsupported casing relieved pressure because the bolt wasn't closed, the pressure pushed casing out to point where it can't hold pressure with just brass, and Kaboom. That almost never happens with any AR Kaboom, though it's the first thing everybody says. And like every other AR Kaboom, that's not what happen here either.
This was a massive overpressure event - enough to cause the brass to flow and extrude back into the ejector hole. An OOB wouldn't get anywhere near pressure to do that. In fact, I doubt an OOB would ever get up to normal rated pressure before popping. It takes a massive amount of pressure to flow brass like that bit of extruded brass back into the ejector there. That was an over-pressure event, to cause that. Considering it's Frontier ammo, very probably a bad round. That aside, I can't say I really recommend just throwing in a bolt and keep on firing like that. The event could have weakened or cracked your barrel extension. |
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See how the web of the casing looks like it's been converted to a belted magnum?
That's a classic sign of firing out of battery - the case was not completely in the chamber when it fired. Otherwise that part of the case would have been supported. A properly functioning AR15 cannot fire out of battery, but that casing sure looks like it fired out of battery. There's likely some other problem. |
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My vote is massive over pressure. The plastic extrusion into the ejector channel indicates this. There was still a lot of pressure in the chamber when the bolt unlocked which caused the “belted magnum” look. |
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That aside, I can't say I really recommend just throwing in a bolt and keep on firing like that. The event could have weakened or cracked your barrel extension. |
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See how the web of the casing looks like it's been converted to a belted magnum? That's a classic sign of firing out of battery - the case was not completely in the chamber when it fired. Otherwise that part of the case would have been supported. A properly functioning AR15 cannot fire out of battery, but that casing sure looks like it fired out of battery. There's likely some other problem.  M1's and M1A's are much more susceptible to OOB due to how their firing pin timing control and retention systems work (subject to wear, and heaven help you if it's a reweld receiver). And here's what the brass from those OOB and slamfires looks like: 
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Quoted: Thanks for the input. I am really going to be pissed if this killed my rifle. Is there a practical method to have the rifle checked for any cracked components? I can't believe Hornady would not recall this shit if this continues to happen. You could even try calling Colt. They could probably help or suggest the next course of action. |
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Were any of them heavier than 55 grain? Seems like everything I see is the 55gr stuff but was looking at the 75's and maybe the 68's and get nervous when I see these threads I put another 200 rounds through the upper today with a new Colt bolt, shot Federal 55gr. Everything seems ok, I know some people think it was a bad idea. Should I re-barrel the upper and just toss the barrel or say "fuck it" and keep rocking out? |
| You should send an actual on paper letter to Hornady, c/o the President, and include this thread URL. You might also mention how many of us are not going to buy Frontier Ammo, and how we are telling others, and they others, and so on. Even Wolf and Tula can somehow manage to not explode rifles. |
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You should send an actual on paper letter to Hornady, c/o the President, and include this thread URL. You might also mention how many of us are not going to buy Frontier Ammo, and how we are telling others, and they others, and so on. Even Wolf and Tula can somehow manage to not explode rifles. |
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Quoted: Pretty sure this was 55gr. I wish i saved the box but I tossed it when I charged all the mags. I put another 200 rounds through the upper today with a new Colt bolt, shot Federal 55gr. Everything seems ok, I know some people think it was a bad idea. Should I re-barrel the upper and just toss the barrel or say "fuck it" and keep rocking out? |
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Quoted: Pretty sure this was 55gr. I wish i saved the box but I tossed it when I charged all the mags. I put another 200 rounds through the upper today with a new Colt bolt, shot Federal 55gr. Everything seems ok, I know some people think it was a bad idea. Should I re-barrel the upper and just toss the barrel or say "fuck it" and keep rocking out? Was the KB round the last round in the mag? If not, the remaining ammo should be sent to Hornady for testing. If it was the absolute last round you had of this ammo and you threw the box away, I would imagine you're SOL. |
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So you don't have any more of the Frontier ammo and you don't have the box with the lot number that the KB round was in? Good luck getting Hornady to take responsibility. Was the KB round the last round in the mag? If not, the remaining ammo should be sent to Hornady for testing. If it was the absolute last round you had of this ammo and you threw the box away, I would imagine you're SOL. |
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Quoted: I have about 8 rounds of it left in the same mag I used when it failed. Stopped shooting it immediately. I informed Hornady over the phone that I still had some of this ammo that I could provide for them. It's been two days and still no response from them. |
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Attached File Attached File Attached File Had a friend at the range that showed up with Hornady Frontier this last weekend that he got a "deal" on because the dealer was unloading all of his stock cheap. About 100 rounds in, he had a failure to eject and this is what he pulled out. A near Kaboom. If you look at the base you can see the buldge. It was in a 100% unmolested Springfield Armory Saint he picked up just a few weeks ago. Forgot to say that it was 55 grain 5.56. |
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Were any of them heavier than 55 grain? Seems like everything I see is the 55gr stuff but was looking at the 75's and maybe the 68's and get nervous when I see these threads |
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That's sucks. Fuck hornady. ETA their techs are also morons if they think carbon on a case indicates OOB. No box, no receipt, no lot number. What are they supposed to do? There are so many shady people in the shooting world, they would go out of business 20 years ago. Besides what's the damage, a new bolt? |
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It would seem to me that a heavy overcharge which creates massive overpressure MUST cause faster than normal operation of the gas system, allowing the extraction process to begin while case pressures are still way high. That explains the belted magnum appearance and other forms of case rupture. What rock have you been hiding under, that you don't know that Frontier ammo is what you give to people you hate? |
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I gotta say... that amount of carbon build up is negligible, IMHO. And any allusion that the carbon build up contributed to a out of battery discharge is nonsense , based on your photos.
As for the lack of a lot number, that would help considerably. No way for the store to be able to track a Lot # of an ammo shipment ? ... even with Hornady help ? Do ammo manufacturers record what lot of ammo is shipped where ? Probably not... but... Can you dumpster dive for the OEM box ?... any possibility ? And I am surprised Hornady didn't ask about the 8 left over rounds. |
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Hornady as a company is a shell of it's former self and I would no longer purchase any of their products. Just a few months back I purchased a quantity of their 5.56 55 grain GMX rounds. Their velocity chronied over 100 FPS under the advertised velocity. Hornady didn't care and couldn't understand why it was an issue that the ammunition was 100 FPS off of their advertised spec. I asked at what point they would care about velocity difference? 300 FPS? I was told that 300 fps under spec MIGHT be a cause of concern for them.
F them. I am curious though, isn't Hornady's "Freedom" line loaded by Lake City ammo plant, the same as Federal and Winchester now? How can there be so many issues with one brand over another when they are all loaded at the same plant? |
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Hornady *always* says OOB for these severe overpressure events.
Which is complete and total bullshit.... OOB doesn't look remotely close to this. The damage you had only happens when the bolt is in battery. Frontier ammo has MANY, MANY instances where this has blown up peoples guns. https://www.ar15.com/forums/ar-15/Will-Frontier-5-56-blow-up-my-gun--UPDATE-ON-Page-1-/16-735682/ https://www.ar15.com/forums/General/-ARCHIVED-THREAD-Witnessed-a-KABOOM-today-Updated-pics-on-page-5/5-2145296/?page=1 https://www.ar15.com/forums/AR-15/My-AR-exploded-in-my-face-today--Can-anyone-tell-me-why-/66-731445/ 
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That's rather harsh. No box, no receipt, no lot number. What are they supposed to do? The "must have receipt/lot number/box" is only needed for internal QC measures, not replacing a rifle they kboomed |
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OP's photos and FALARAK's photos above show that this is a massive over-pressure kaboom and not an out-of-battery (note in the post above the shoulder and neck are intact and not blown-out).
Note the chamfer curve on OP's brass from the rear of the barrel face into the locking lug section of the receiver extension: 
This illustration generally shows that the chamber doesn't fully support the case down to the extractor groove: 
Just one of the reasons I'll shoot Hornady ammo (if it was bought by someone else for work) but won't buy it if it's my money. The system held, and failed at the weakest point (the brass case trying to hold in excess of 70,000 c.u.p. proof pressure, letting go at the weakest point of support -- the extractor groove in the bolt). Sounds like Hornady gave you the F.U. Meh. Shit-can whatever you have left of this box/case/lot. New bolt assembly and go back to work. |
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I don't handload, so I am not super familiar with the amount of powder that goes into a 5.56 case. Isn't it pretty much full? How is this Hornady ammo reaching such high pressure? Is it incorrect powder? |
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The blown out case stamped with frontier on it is enough to ID it. The "must have receipt/lot number/box" is only needed for internal QC measures, not replacing a rifle they kboomed Quoted:
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That's rather harsh. No box, no receipt, no lot number. What are they supposed to do? The "must have receipt/lot number/box" is only needed for internal QC measures, not replacing a rifle they kboomed His could be a reload. I'm not saying it is, but with no paperwork who could say. |
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I don't handload, so I am not super familiar with the amount of powder that goes into a 5.56 case. Isn't it pretty much full? How is this Hornady ammo reaching such high pressure? Is it incorrect powder? https://www.ar15.com/forums/AR-15/5-56-and-M193-Velocity-Shoot-Off--Bonus-Part-I/16-733701/ |
[ARCHIVED THREAD] - Frontier 55 grain boom and damaged extractor. *update Hornady says pound sand (Page 1 of 5)
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