What Is This???

[cohunter14]

I have been working on my father's 7 RUM recently and trying to figure out some issues with it. Lately it has just lost some accuracy so today I took it out to try to do some digging and figure out what the issue is. Unfortunately he only had five reloads left, so he grabbed a box of Nosler factory ammo on his way out. Luckily he shoots 160 Accubonds in his reloads that go 3,325fps and this box was 160 Accubonds that are supposed to be 3,225fps.

Long story short, I ended up needing to fire more than five shots, so I grabbed the box of Nosler ammo and loaded one up. It shot very similar to the reloads, but when I extracted it, the case looked like this:





What in the world would cause this? I wouldn't think you would have to worry about pressure from a factory round, especially when it's rated at 100fps less than his reloads, but it is Nosler brass instead of his standard Remington brass. Anything else that could cause this?I packed up and headed home after this as I wasn't willing to shoot another round after that happened.

For the record, there are no pressure signs at all on his reloads and I did let the barrel cool a good 3-4 minutes before shooting that round.

 

[MudRunner2005]

Usually a dented shoulder/neck is an indicator of an undercharged round. 100 fps would not cause this issue if you're still pushing a 160gr bullet to over 3,200 fps...It would have to be a very undercharged round or bad powder (moisture or inert from age and air or not being properly stored or sealed) that did not properly combust causing low pressures. Shake them to see if they sound like they're mostly full. If they sound light, then weigh the loaded rounds to be sure.

Or, you could also deconstruct the round... Pull the bullet, dump the powder, and weigh and load fresh powder into it, and check for pressure signs to be sure your lot of powder is not hotter than the old powder.

 

[cohunter14]

Okay, that makes me feel a little better. I was hoping that was the deal! Is there any issue in still shooting this ammo, or is it best to probably wait and load up more when I get a chance? Is it even worth keeping the brass either? Probably have to fire form it before using it again I would guess, right?

 

[MudRunner2005]

Okay, that makes me feel a little better. I was hoping that was the deal! Is there any issue in still shooting this ammo, or is it best to probably wait and load up more when I get a chance? Is it even worth keeping the brass either? Probably have to fire form it before using it again I would guess, right?

It might be best to buy a fresh jug of powder and pull the bullets and reload them...Just to be sure.

Yes, you will need to fire-form that round back to shape before loading up a full charge. I would use a lighter load charge (use about 10 grains less powder than the book's recommended starting load) that way you don't overpressure and blow out the shoulder. I use this method with fire forming brass for my Ackley Improved rifles.

 

[cohunter14]

So just to be clear, a factory load can be under charged enough to cause this? It just seems weird to me that a factory load would do this.

 

[MudRunner2005]

So just to be clear, a factory load can be under charged enough to cause this? It just seems weird to me that a factory load would do this.

I missed the factory part... Not likely, but I suppose it could happen. Anything man-made has the potential for failure or the occasional screw up. Machines are only as smart as the people who program them.

If it were grossly overcharged, most-likely it would have split the case, but now I'm confused without seeing the case in person. Still looks like an undercharged round to me.

You might want to contact Nosler and find out what they suggest. They might send you another box of ammo?

 

[cohunter14]

I'm just nervous about pulling the trigger again. I could shoot another factory load and see if it does the same thing, but even that has me nervous at this point. I could just wait and reload some and see if those shoot fine as well. I mainly want to make sure I'm not going to have the rifle blow up on me if I shoot it again.

By the way, the chamber area and action all appear to be fine...

 

[LoneTraveler]

Looks like Low Pressure to me. Seen that happen years ago with a 264 WM. it was caused by light powder charges.

If they are factory rounds. I would weigh the loaded rounds left and contact the manufacture. They should be able to tell you if they are light loaded by the weight of the remaining targets.

GOOD LUCK and Be Safe.

 

[codyadams]

Factory loads are certainly not immune. My buddy had some factory 30-06 Federal Fusion 165 grain ammo, box stated it was going 2800 fps. He was shooting a Howa. After 2 years of hunting with it, he wasn't satisfied with its performance, one small cow elk he shot at 90 yards was hit behind the shoulder, didn't hit any ribs, and the bullet was inside the rib cage on the off side. It didn't act like it was even hit when he shot, and his cousin shot it in the neck and dropped it. He wanted to buy a new rifle, but I told him I would look at it, as a 30-06 should perform better than that.

First thing I did was chrono them. They were going 2150 fps. Fired 10 rounds over the chrony, then immediately fired 5 rounds of my .223 over it, and the velocity was correct with what I knew those rounds to do. I pulled the bullets, and there was 57 grains of a large extruded grain powder, which 57 grains doesn't give that low of a velocity with any of the powders listed in my reloading manuals. My only thought is they used the wrong powder, one that was much slower burning and simply didn't get the pressure up. My thought was "good thing they didn't screw up the other way and mix it up with a faster burning powder that would blow up the gun due to overpressure..."

I loaded him up some 180 grain ballistic tips @ 2810 using H-4350. He has since killed 4 elk with 6 shots.

Also, I went to federals site to inform them of this, and when I did they had a recall on .243 ammo, stating that your firearm could be damaged if you fire it in your gun due to overpressure because the wrong powder was used. To the people that shoot factory ammo...how often do you go to you ammo manufacturers site to check for recalls? Probably not at all. This is a mistake that should not be made by ammo manufacturers.

Moral of the story, I will not ever buy factory ammo, I do not trust it. When I'm dealing with 55,000-65,000 PSI explosives 5 inches from my face, I prefer to roll my own. That way if I blow myself up, at least it's my fault, and not some guy in a factory that was having a bad monday.

 

[Frank in the Laurels]

Pull a bullet weigh the charge, you won't be first or last person to be off a little..maybe you bumped you slide on your scale by accident...way under charged...I'd think you'd be able to feel this in far less recoil. I doubt it's the powder explosiveness since you've been using it..and the factory can be off also, maybe the powder machine messed up...not unheard of but rare...

 

[MudRunner2005]

Pull a bullet weigh the charge, you won't be first or last person to be off a little..maybe you bumped you slide on your scale by accident...way under charged...I'd think you'd be able to feel this in far less recoil. I doubt it's the powder explosiveness since you've been using it..and the factory can be off also, maybe the powder machine messed up...not unheard of but rare...

I missed that at first, too...But he said it was factory ammo that did this.

But I also suggested he pull a bullet and weigh the charge to see if they've made a screwup...

 

[shortgrass]

Factory loads are certainly not immune. My buddy had some factory 30-06 Federal Fusion 165 grain ammo, box stated it was going 2800 fps. He was shooting a Howa. After 2 years of hunting with it, he wasn't satisfied with its performance, one small cow elk he shot at 90 yards was hit behind the shoulder, didn't hit any ribs, and the bullet was inside the rib cage on the off side. It didn't act like it was even hit when he shot, and his cousin shot it in the neck and dropped it. He wanted to buy a new rifle, but I told him I would look at it, as a 30-06 should perform better than that.

First thing I did was chrono them. They were going 2150 fps. Fired 10 rounds over the chrony, then immediately fired 5 rounds of my .223 over it, and the velocity was correct with what I knew those rounds to do. I pulled the bullets, and there was 57 grains of a large extruded grain powder, which 57 grains doesn't give that low of a velocity with any of the powders listed in my reloading manuals. My only thought is they used the wrong powder, one that was much slower burning and simply didn't get the pressure up. My thought was "good thing they didn't screw up the other way and mix it up with a faster burning powder that would blow up the gun due to overpressure..."

I loaded him up some 180 grain ballistic tips @ 2810 using H-4350. He has since killed 4 elk with 6 shots.

Also, I went to federals site to inform them of this, and when I did they had a recall on .243 ammo, stating that your firearm could be damaged if you fire it in your gun due to overpressure because the wrong powder was used. To the people that shoot factory ammo...how often do you go to you ammo manufacturers site to check for recalls? Probably not at all. This is a mistake that should not be made by ammo manufacturers.

Moral of the story, I will not ever buy factory ammo, I do not trust it. When I'm dealing with 55,000-65,000 PSI explosives 5 inches from my face, I prefer to roll my own. That way if I blow myself up, at least it's my fault, and not some guy in a factory that was having a bad monday.

I have seen many, many more screw-ups made by handloaders than I've seen recalls of factory produced ammunition (and I get the recall notices, because I'm in the industry). NO ONE on this earth is immune from mistakes! The harder you push production employees for more, more, more,,,, the more quality suffers. The demand has been at an all time high. Maybe folks will relax a bit now that the election is over.

 

[codyadams]

I have seen many, many more screw-ups made by handloaders than I've seen recalls of factory produced ammunition (and I get the recall notices, because I'm in the industry). NO ONE on this earth is immune from mistakes! The harder you push production employees for more, more, more,,,, the more quality suffers. The demand has been at an all time high. Maybe folks will relax a bit now that the election is over.

I agree, there are far more mistakes made by hand loaders, that is for sure. But for me personally, I trust my ammunition more when I load it myself. Yes, out of a million or even more rounds loaded by factories there may only be one round that could create a dangerous situation, but I know exactly the kind of care and attention to detail that goes into my rounds. Same reason why I have my own laying chickens, our own beef and pigs, and why we hunt for meat. I like to know exactly where my stuff comes from, if that makes any sense...ha ha.

 

[Deleted member 46119]

I have seen this. In other peoples rifles.

First, lets see if I an answer the original question: what caused this?

If my understanding is correct, the "cause" is the neck of the case not sealing to the chamber. The "blow by" of the powder residue on to the shoulder supports this.

Next, what caused the neck to not seal against the chamber?

If my understanding is correct, there are multiple contributors. "Old" stiff brass? Over diameter chamber in the neck area? Degraded powder in the "old" factory rounds? Maybe more things?

From your pictures, it appears that the body of the case did seal against the chamber, saving you from receiving a face full of hot gases.

How do you prevent this from happening in the future?

That box of factory ammo is suspect. If it were me: pull the bullets, weight the charges. etc... Basically don't use that box as loaded.

Anneal necks. The neck has to seal to the chamber before the gasses get past the shoulder. Minimal resizing or neck sizing only also helps with sealing.