What did I do wrong here?

[ADClope]

Still zeroing in this new RPR 6.5. Ordered some 6.5 hornady reloading brass, and some 143 grain ELD-X's. Had about 1/3 lb of Hodgdon Superperformer left over so I wanted to finish it off and loaded these up with 42.2 grains. COL set to 2.802"

40 of them fired just fine and the primers looked okay. This one fired, POI was about 4" higher than the rest of the group and I noticed a lot more smoke coming from ejection port and magwell. Pulled the case out and noticed the burn hole between the primer and the case, so I pulled the bolt and noticed that it burned a pit in that as well. Packed up and stopped for the day at least until I can figure out what caused this. Also, is the bolt junk now?

Any ideas welcome, somewhat new to reloading so I'm wanting to know what I did wrong here.

Thanks





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[tangolima]

Over pressure in the round. Bolt is OK.

-TL

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[zplinker]

You may have been the victim of a poor piece of brass. I've run into that, using new brass, and had I not been chronographing to show my loads were all within specks, there would have been no way to know what happened. How do you avoid it? IF you find out, tell me.

[condor bravo]

Sounds like a weak piece of brass; have had that happen also. Don't take the blame for this one. Bolt should be OK.

[briandg]

Great high resolution picture. Looks to me that you had big expansion of primer pocket and then an actual burn through pin hole. That caused flame cutting on both bolt and case head. Maybe it was a problem with the brass case head, but I'm thinking that the case was subjected to extreme over pressure in some way.

Regardless, that wasn't just a harmless little puff of leaked gasses,that scored the steel of your bolt.

[condor bravo]

And am I correct in saying that your shooting glasses kept things from becoming much worse? Escaping gas from a burned through primer pocket or case head comes out with considerable force.

[Metal god]

I agree it could have been bad brass or loose primer pocket how ever .

Have you shot that component combo over a chrono ? If so how consistent was it ??

There are many things to ask here that could lead to the problem .

How strong is your bullet hold ? Meaning how are you sizing your cases ?

What primers are you using ?

How far off the lands is the bullet ?

I have a theory that has to do with slow powders and primer causing the bullet to release jamming into the lands before the powder really gets going .I've bad erratic performance with both 223 and 308 when using slow powders . The growing theory is the bullet is being pushed out of the neck by the force of the primer ignition causing inconsistent ignition of the powder .

So then think about the possibility that your otherwise safe load at .020 off the lands becomes over pressured when the bullet jumps into the lands and then the powder burn spikes as if you started that cartridge jammed into the lands . Unclenick is much better explaining this issue and he very well come in here and explain that ain't happening here . I'm just throwing it out there .

[Nvreloader]

ADCLope

You didn't state what primer you are using, but there has been numerous reports of defective primers,
one lot of Rem 7-1/2 were really bad, blowing out just like your photo's, with normal loads.

Is all the brass the same brand name?

You can do a H2o capacity test on that case, just plug the blown primer hole, to hold the H2o in,
and do a random 5 rd test of the other brass.

This test will show if this pc of brass is within the normal internal range,
of all the other brass in this lot, etc.

Here is a u tube post of how to do it,
https://www.youtube.com/watch?v=NMEtfT-e0eg,

He is very sloppy when filling the case, and he did not add a couple of drops of dish soap to the water, as you can see he had to fill case #3 again,
the dish soap stops the bubbles forming inside the case, and used a lot of pressure when filling the case,

When filling the case, you can slowly add the last couple of drops of water, to bring the water level to the very top of the case neck etc.

That is why I use a needle to fill with, and when finished, I can suck up almost all the water out of the case, when finished and reuse the water for the next case etc.

Tia,
Don

[Sure Shot Mc Gee]

I do not like Hornady or Frontier brass. Pressing primers into either seems to be troubling for me. Kinda like the brass's primer pocket is tapered or too small or something? Than again I don't prime my brass in the same manor everyone else does. I have a old Pacific brass trimmer that seats Large pistol or rifle primers to the very bottom of their pockets in any brass >after their initial seating on a Rockerchucker press. Anywho Federal or Winchester rifle brass I much prefer over Hornadys any day of the week.

[F. Guffey]

Any ideas welcome, somewhat new to reloading so I'm wanting to know what I did wrong here.

If that was my bolt I would say I allowed the problem to get out of hand because I do not agree with the problem has only happened once. And then there is pressure, I would compare the primer dents; the dent in the primer does not show evidence of pressure.

And then there is my concern; I am the fan of cases that are not work hardened, I want my case heads to expand when fired, I do not insist on a lot of expansion but I prefer case heads to expand .00025" with factory like loads. And then there is the speed of powder burn, I prefer the burn to be like BAAAAANNNNG, not BG!, I want my bullet to get moving first and then once down the barrel I want my pressure to get serious. There is nothing entertaining about a sending a bullet out the barrel when the powder burn does not give it enough time to get moving.

That is not your problem, if you had measured the case head diameter before you fired the case you could measure the case head diameter after firing. And then there is measuring the weight of the components, you could have determined if one of the bullets was too heavy and or if one of the powder charges was too heady.

F. Guffey

[F. Guffey]

And then there is the crack in the case before you started. No one has enough discipline to develop the technique but; a reloader could test ammo for cracks by placing loaded ammo in a glass jar filled with enough water to submerge the cases; and then place a vacuum on the jar. Leaks can be located by bubbles.

F. Guffey

[briandg]

Is it possible that the primer cup had a split or wrinkle?. I keep looking at that pinhole where the leak formed.

[ADClope]

All,

First of all, thanks for all the replies and comments.

I will check the primer brand again tonight to verify. I got them at a gun show, benchrest primers I believe, large rifle, appear to have different colored coatings, some green, some red, a couple different brands. I will verify tonight. I assumed, maybe incorrectly?, that large rifle would be large rifle and should be safe to load these rounds with. Nothing was labeled as "magnum" large rifle.

All brass is Hornady reloading brass.

Using Hornady 6.5 dies for resizing. OD of case mouth is .289 after sizing, and .2905 to .2910 ish after bullet seating, so neck tension seems to be in the .0015 to .002 range, which I thought was acceptable.

All rounds were set to a COL of 2.800 or very close to there, whatever variance there was in the seating die.

Powder was set at exactly 42.2 which appears completely safe according to the loading manual. Used a powder throw to get to about 40, and then trickled up to 42.2, so I'm positive they were not overcharged.

I have not used a chronograph with these loads yet, I'm thinking I should.

So if indeed the round was overpressured, I do not understand why. I have not checked how far off the lands the bullet sits with COL of 2.800.

Thanks again all for the help

[ADClope]

Also to note, some primers did seem to seat a little differently than others, as far as how "tight" they were. Some were pretty snug, others a little less so. But none of them were anywhere near what I would consider "loose"

What is a good gauge on how "tight" a primer should feel going in?

[condor bravo]

Re: post #12
Note that the leak did not form at the pinhole, but rather the escaping gas followed the path of least resistance between the primer and primer pocket, rather than through solid metal, and exited at a point around the diameter resulting in the pinhole.

[briandg]

If I'm understanding what you said, I'm not sure if I agree. This doesn't look like a gas escape that worked it's way between smooth surfaces of primer and pocket.

The primer itself was obviously pressed so hard to the bolt face that the soot didn't form on it. Right next to the H a pinhole has been burned through, and erosion from what must have been a hellish flame gouged the primer, case head, and even bolt face.

I keep thinking about this and looking, and the things I'm seeing lead my to think that maybe the primer itself failed. That had to have been a lot of gas.

I don't understand what would have caused a four inch rise in poi, but distance isn't given. That seems to be literally impossible to do at short ranges just by increased pressure elevating velocities by a percent or three.

[briandg]

I guess that I'm convinced that the primer cup failed. I believe that I'm seeing a split to the left, and at the pinhole, it appears that part of the cup is smeared over the case head.

[ADClope]

Distance was only 100 yards.

I will pull the primer out tonight, and try and get some more pictures inside the pocket and cut the mouth/shoulder off the case to look down in there too since the case is trashed now anyways. Maybe it will help to see it taken apart?

So if indeed the primer failed, and since I don't know for sure the exact history of these primers (meaning I didn't personally buy them new), should I pull all of the rounds I've loaded thus far and replace all the primers?

Thanks

[Stats Shooter]

Im going to need some more pictures here, but it is either the side of the primer pocket, or the primer.

Once you punch the primer out, look at the pocket. It is possible that the flash hole is way off.

I have pierced primers before, by that I mean the firing pin punched punched the dimple in it, then the pressure went ahead and punched out the primer dimple making a hole. This happens with too much pressure, but the damage was nowhere near what I am seeing on your case, which makes me think that it happened very early in the ignition sequence whereas the pierced primer likely happens at peak pressure when the bullet is already moving down the barrel.

You said that while seating primers everything "felt normal". But if the primer pocket was "out of round", having a channel and the primer wasn't able to seal the pocket, then this could have potentially happened.

It wouldn't do much good to go back and check if it was out of round now, because you wouldn't know if it were that way initially. But given the score on your boltface (which is fine btw), I think this happened very early in the burn sequence, and was either a messed-up flash hole/primer pocket and NOT a pressure issue. Because if it WAS a pressure issue and everything else was within speck, you would either have a pierced/blownout primer or a crack in the case or something.

[F. Guffey]

I have pierced primers before, by that I mean the firing pin punched the dimple in it, then the pressure went ahead and punched out the primer dimple making a hole. This happens with too much pressure,

Or the firing pin spring is not strong enough to hold the pin against the primer as pressure builds.

F. Guffey

[Unclenick]

Brass color looks like a Winchester primer, though some of the foreign ones don't nickel plate the cups either. There have been some complaints about some lots of Winchester primers piercing and leaking like that. The flattening is pretty noticeable, but not unusual by itself. I would switch to something harder like a CCI and see if the flattening is reduced any.

I'll mention also that I've seen primers in loaded rounds go from rounded to flat with the same partial case fill charge, depending whether the powder is forward over the bullet and away from the flash hole, or backward over the flash hole. Tilting the loaded gun forward or upward before coming level to fire will create these two conditions. If you develop a near maximum load always tilting powder forward, then tilt it up for one round during shooting, that could happen.

I've seen many a Garand bolt with rings of those pierced primer marks around the flash holes. It doesn't affect function, but it is annoying, especially on a new rifle.

[ShootistPRS]

ADClope,
It might be that you have some large pistol primers in your batch of gun show primers. They will blow at rifle pressures. In your load data I did not see the bullet that you were using listed. You may be using a bullet of different construction, that is longer, both of which might increase pressures. If all the loads used the same powder and bullet it is unlikely that the bullet is problematic. I only buy primers in retail distributors that can't be easily mixed with other primers. You should check for load data that uses your exact bullet.

[Stats Shooter]

It might be that you have some large pistol primers in your batch of gun show primers. They will blow at rifle pressures. In your load data I did not see the bullet that you were using listed. You may be using a bullet of different construction, that is longer, both of which might increase pressures. If all the loads used the same powder and bullet it is unlikely that the bullet is problematic. I only buy primers in retail distributors that can't be easily mixed with other primers. You should check for load data that uses your exact bullet.

Something similar happend to me and it wasn't a gun show. I wanted to try BR-2 primers vs the usual CCI-200's I use in a load I was working up, but didn't want to buy several bricks until I was sure I wanted to go that rout since BR-2's are almost double the cost of CCI-200's. So I just bought 2x100 primer sleeves. But 4 of the primers in one of the sleeves were CCI-BR4's!!

This was obvious since small rifle and large rifle primers are not the same size. I called CCI and they said this was impossible at the plant because they are made and packaged in totally different areas. So since they were new sleeves, probably some employee at the store I bout them from dropped several and just guessed where they go.


Since you bought them at a gun show and didn't specify how they were packaged, this could have easily happened Since the only visual difference between LP and LR primers is that LR primers are .008 taller. BUT! LP primers are designed to operate at far lower pressures and lighter firing pins.

[ADClope]

Thanks for all of the help and comments.

I wonder if it'd be worth measuring the primer height tonight after I punch it out. Does anyone know the specified height of a large rifle primers vs pistol? I'm sure I can easily find it by googling it if not.

I'm starting to really wonder now if that's what happened here...

[Unclenick]

The rifle primers are about a hundredth of an inch taller. The problem is their allowable range overlaps. Large Pistol are supposed to be 0.115-0.126" tall, while large Rifle are 0.123-0.136" tall. That said, I think most of the large rifle primers I've measured have tended to be around 0.127" plus or minus a thousandth or two, and large pistol about 0.117" plus or minus a thousandth or two.