I would like to start out with saying hello and thank you for the forums. I’ve been shooting AR’s since 2006 and been reloading for 4 years as well.
I have shot this specific load thousands of times and had no previous signs of pressure issues.
Anyways info on the gun 10.5" SBR suppressed LMT upper CMMG lower.
This was the first round of a new magazine and the bullet did hit the target and most importantly no one was hurt.
Load info 1x fired LC, 24.6 g H335, wolf magnum primer, 55g V-max bullet. Loaded on Dillon 650.
I always inspect (with a case gage) all brass twice once after sizing and once again when the round is completed. I really don’t know how I could have gotten an extra powder charge as I always look at the powder when seating the bullet and I also have the alarm on my press when powder doesn’t fall within the correct range.
Anyways I do need to re-examine my load and the rest of the rounds and try to figure out what happened.
Any input would be appreciated I know I’m lucky no one was hurt and I take pride in loading good ammo this has shaken my confidence somewhat but I also know I have shot thousands of this round with no issues what so ever.
Finally, the upper receiver and BCG is toast I don’t know about the barrel is it still OK to use?
Wow. What was your load specifics? Were there any other rounds that fired normally before this mag? What equipment are you using to meter powder and charge, etc.
That’s more of a case failure (obviously due to excessive presure) than a separation.
In my opinion, you’re going overboard with the case gauging. Set the die with the gauge and be done. I gauge brass MAYBE every few thousand just to check.
I have fired at least 2500 of this round and had no issues until this. This was not the first round fired this day but was the first round in a new magazine.
LC 1x, 24.6 g H335, 55g V-max, wolf SRM primer, crimped bullet. Dillon 650 is my press and I do use a powder alarm.
Yes I may be going overboard with the case gauging but I just check every round with it to make sure something wasn’t missed. I do not make any adjustments after every round.
Case head blown, nasty. Huge brass flow into the ejector, which would indicate big over pressure as opposed to a weak case head. I’m with Onyx Z on this one, bullet setback sounds like. I put a light crimp on even non-cannelure bullet to fight bullet setback.
Oh I’m sure it was a pressure issue and I’ve been leaning on the bullet setback. Is there a reliable way to test the crimp I may just knock every bullet on my bench to see if the bullet moves back. I was just posting this here to see what other people think as more peoples thoughts are usually better in a situation like this.
Also does anyone know if my barrel is good to go I don’t see any damage in it but I just don’t know? I’m leaning on no with the barrel due to too much pressure but if someone knows for sure please speak up.
You can get WOLF primers to work with H335? They usually cause hang fires and stuff.
Odd though. The load isn’t that hot, and H335 shouldn’t give you metering issues. I’d pull a few bullets down and spot check the powder charge. I’m not a huge believer in bullet set back. I’ve had it happen with some goofy hollow point surplussed bullets, and it’s always caused a misfeed for me.
I’ve never had an issue with the small magnum primers and H335 even though I’ve read about it. I know I need to obviously look at all these rounds and at the very least break some down but I’ve literally shot thousands of these from this batch and had no issues. I usually load in bulk 1-2k at least.
I’m chalking this up to a fluke… assuming your powder charge audits check out.
You could check bullet tension before and after crimping to see if some die or step in your process has gone awry. Just finger twisting the bullet is adequate. No need to smack the round on the bench.
With 24.6 of H335, the bullet could be set back quite a good bit and not kaboom like this. There has to have been a mechanical issue that let too much powder into the case.
The Wolf magnums seem to work well with ball powders. The standards don’t seem to have enough horsepower, I was getting hangfires and no fires alot with them. I moved on.
Again… I bought these screwball hollow point Federal contract surplus bullets that were horrendous. (obviously I know why they surplussed the component now) I had 5 or 6 set backs in several guns. Never did the round make it to chamber.
Pain in the ass though. Would puke powder into the barrel extension area and make a mess. I could be wrong, but I just don’t see it if you have normal neck tension otherwise.
Bullet setback in a rifle is not going to create an over pressure problem. It does not take up a large enough volume in the case tho create an issue. There have been test where bullets were intentionally setback by an extreme amount and velocity was either the same or slower. In rifle cartridges pressure is reduced the farther from the lands. It increases as the bullet gets closer to the lands.
It is one of the most misunderstood concepts of reloading. Everyone figures because it is true for pistol it has to be true for rifle.
Good to know. Some guys on here said they were gtg, but that’s not true for all obviously. I’m moving on from ever using those also. If I’m diligent I can find 1 pounders at my local stores, but the 8 pounders have gone extinct around here. I’ve pretty much given up on the mail order houses.
The case setback and still chambering is unlikely, but crazier things have happened.
Obviously there was a huge pressure spike, so there has to be some kind of overcharge, bullet setback, etc. Maybe a long/heavy bullet (77gr) slipped in there? I don’t see what else it could be.
No clue about the barrel. If it were mine, I would replace it without question.
I had a case head let go very similar to this one (didn’t damage the gun) where I know I had a good crimp working. I sometimes wonder, if for some unknown reason, that in an otherwise sound cartridge the powder, instead of burning just sort of detonates. We’ll never really know what happen, all we can do is be as careful in assembly as we’re capable of.
