Gas Leaking Around Primer

[mtnlvr]

Looking for some experience on this. I've got a couple pieces of 270WSM fired brass that have this condition. Thoughts on what contribute to a failure like this? I have little history with the brass, I've fired it twice, it came in a baggie with my rifle. The load was 60.5 gr of IMR4350 with a 140 gr Hornady SST and a Winchester primer running about 3100 fps out of my 24" Tikka barrel.

 

[dprice3844444]

dillon makes that primer pocket swager

 

[GooseGestapo]

The blow by is from a worn/loose primer pocket. Discard the brass. As you see, it's already etched the face of the bolt. I've had such from weak, damaged brass with oversized primer pockets. (but not from a WSM).

I recently had a 3x fired Federal .30/06 case do the same in my .338/06. However, it wasn't even loaded as warm as your load.

Thats a Hodgdon max load you're loading and it's listed with a Winchester case and a Win. Large Magnum primer. You are using neither! From appearances you're using in addition to Federal brass, a CCI or Federal primer.
The Federal brass in my experience is 2-3% lower in case capacity.
Speer lists 60.0gr as max with a 130gr bullet with Winchester brass and CCI #200, which is a standard primer. And, it isn't even as hot as a Federal 210 primer.

I suggest you back down your load ~5%.

 

[243winxb]

Defective Primer or Loose Primer Pockets?

Defective primers can have a weak spot that will blow out even at midrange pressure. Remove the primer to see if the side of the primer is still intact. Look for a hole in the face of the primer. The hole is most times in the radius of the primer like here. When there is gas/pressure leakage in the primer area, 2 things are possible. Loose primer pocket OR Defective Primers. On way to tell is by looking at the primer. If the side of the prime is intact like this one, you have a defect. Hot gas from a loose primer pocket will not be in only 1 area. The side of the primer should show gas cutting. The defective prime will most times, pock mark the bold face, just like a small cutting torch.

 

[mtnlvr]

Thanks for the informative replies guys. I still have a lot to learn.

Thats a Hodgdon max load you're loading and it's listed with a Winchester case and a Win. Large Magnum primer. You are using neither! From appearances you're using in addition to Federal brass, a CCI or Federal primer.

The primer is a Winchester LR. Does the primer really make much of a difference in terms of weakness for letting gasses through? I was told I could us a standard primer instead of a magnum as long as I wasn't having ignition issues. Or is this an ignition issue?

The Federal brass in my experience is 2-3% lower in case capacity.

So if I understand you right, with the lower case capacity I get more fill with a given charge and the result is higher chamber pressure?

Speer lists 60.0gr as max with a 130gr bullet with Winchester brass and CCI #200, which is a standard primer. And, it isn't even as hot as a Federal 210 primer.

That's with IMR4350? What do they list as a max with a 140gr? It seems odd that Speer and Hodgdon data would be that dissimilar!

Remove the primer to see if the side of the primer is still intact. Look for a hole in the face of the primer.

I'll do that tonight and post pics. I do recall some of the brass accepting primers easier than others, but I don't recall if it was these Federals or the Winchesters.

 

[NCsmitty]

It seems that you're pushing the envelope with that load in that particular rifle. It's also likely that you're creating loose primer pockets with the high pressures that's generated and the subsequent damage to your bolt face from the primer blow by.
In my experience, Federal brass seems a bit more susceptible to loose primer pockets than other brands.
Common sense dictates that perhaps dropping your max level charge by at least .5 to 1.0 grain of IMR4350, might allow more trouble free shooting for you. Your accuracy may need to be checked.


NCsmitty

 

[Slamfire]

Published data is a guide. The pressures they get in pressure barrels are never going to be the same in some one else's pressure barrel or your barrel.

Cut your loads.

Primers are not the same, even within the same brand. Primers are chemical mixes and they don't always come out the same. Sometimes the coffee is strong, sometimes it is weak, even though you put the same amount of grounds in the basket.

Primer changes make a difference. For maximum loads, everything makes a difference, including temperature. Develop loads on a nice cool day, and then on a horrible hot day, blown primers.

When ever you have leaking primers you have over max loads.

So, cut your loads.

A clue as to when the primer pockets are too large, put a primer in, tap the case at an angle on wood. If the primer comes out, the pocket is too large.

 

[P-32]

I have to agree the Federal brass is not helping. Federal brass is soft, thick and has reduced powder capacities. A load deemed safe in other brass will more than likely be over pressured using Federal brass. This is a hard lesson to learn with a burned bolt. Always work your loads back up when making component changes. It appears to me this was more of a brass failure than a primer failure. But dude, if your doing what your pics show you are way way over a safe load using what you are using.

Looking at a Sierra manual, it appears your load of IMR 4350 is just below max using Winchester brass. Winchester brass is at the other end of the spectrum by having one of the thinnest brass cases out there. People like Winchester brass because you can stuff a little more powder in them and be safe doing it for the most part. This does not mean going over published data though. IMR 4350 is a good powder to use. There might be something better but IMR 4350 is hard to beat for speed and accuracy.

I ordered some GI 223 brass one time several years ago to prep and load for Camp Perry. I got 1k of Federal 223 brass. I knew Federal was a little heavier than the Lake City I was using. But I was running out of time and loaded it anyway without working it back up. I took my brandy new Krieger barreled AR. I was popping primers at the National matches for crying out load. I made a vow I would never use Federal brass again.

 

[mtnlvr]

So here are the primers...blown through. I'll be switching away from Federal brass. I only had about 25 anyway. I've got 50 once fired Winchesters and 50 new Remington to use. How do the R-P compare? I suppose I should size trim and do a capacity check.

Will the burned bolt face cause any harm to accuracy or anything? Should I do anything with it?

 

[Slamfire]

Will the burned bolt face cause any harm to accuracy or anything? Should I do anything with it?

I am curious what others might say, but I don't think it is a problem at all.

 

[NCsmitty]

I've had good luck with Remington brass, but you might check capacity, as they are often heavier than Winchester brass.

Make sure that you do not have any foreign material fused on the bolt face, (clean) and the bolt should be ok as long as you have no more issues with leaking primers.
There's no good way that I know to repair the bolt face, other than replace the bolt if it's one piece.


NCsmitty

 

[P-32]

I would think the worst thing that can happen is it just plain looks bad and is going to cause questions. Remington brass is good but not as thin as Winchester. You will need to work those up too. The only Remington primers I use is the REM 7 1/2's in my AR. I have tried large rifle primers and always return to CCI.

 

[Stantdm]

The same thing has happened to my Ruger M77 tang safety bolt. The loads were not close to maximum but there were two cases that the primers leaked on. Same result. The consensus on the question I asked here was that the pits are not an functional problem, just cosmetic. Yours isn't as bad as mine. Correct the problem and it won't get any worse.

 

[mtnlvr]

Thanks for all the replies. I'll be reworking up a load with Winchester brass paying more attention to the primer seating force. I do still have a few hundred LRP to use up but maybe I'll sit on those and pick up some CCI primers.

I'm still curious as to the differences between standard and magnum primers in terms of their wall thickness or strength for resisting blow through.

 

[243winxb]

Your photo looks like defective primers to me. Primers show no other signs of high pressure. But then i never have loaded hot enough to have gas leakage "around" the primer. The bolt face is OK, does not hurt a thing. IMO. Great photos- Edited to see better.

 

[P-32]

When you have a magnum primer it doesn’t necessarily mean you have a stronger cup. What you have is more brisance or power of the primer. Powders like IMR4350 are a stick powder. Stick powders are generally easy to light and does not generally need a magnum primer to get things started unless there is a lot of it. Where magnum primers come into play most of the time is ball powders. Ball powders use a deterrent coating to control the burn rates. The coating is hard to light so a stronger burn is needed to get it going well. The rule is to use the primer the book calls for. Looking at a Sierra reloading manual, it shows using a Winchester large rifle magnum primer in all loads for the 270 WSM data in a Winchester case. Your book could be different. Be sure to start at the starting load when working up your Winny brass.

243, be sure to look at his primer pockets. At some point a primer is going to give out when there is no longer any support around it. I don't care for the look of his brass either. Almost looks like it might have been hard to open as the case heads are a little shiney. I have never had a primer do this to me or any of my reloading buddies. While it could be a weak spot in the primer, I think it was a combo of enlarged primer pockets and high pressure.

 

[mtnlvr]

But doesn't using a magnum primer lead to a faster / hotter ignition and even higher pressures?

And how about my COL? I set these longer than the Hodgdon website which states a 2.800" COL, these were at 2.860". Wouldn't this also lead to a lower pressure? FYI...when I used the modified "slotted neck" brass and used the rifling to find the absolute max COL for this 140gr SST, I got 2.951".

For what it's worth, I have fired nearly 50 rounds with this load, 13 others from the same reloading session, and only these 2 had primer failure.

Mods...feel free to move this thread if you feel it should be in the handloading forum.

 

[Coltdriver]

If you are using brass with lower internal capacity you do get higher pressures with the same charge as a case with higher internal capacity.

Adding a Magnum primer will add more pressure.

So two things I always do.

I always figure out my chamber dimensions with the bullet I am going to use. Depending on the ogive of the bullet the max col will change.

The hottest charge is not always the most accurate. So I use the optimum charge weight method to figure out what load works best for my rifle and bullet combo. Work your way up and observe for pressure signs.

Going with a longer than book col may mean you are stuffing the bullet into the lands. Even more pressure, significantly more, results from this.

So regroup and work your way up. And I agree those primers do look suspect. I would not use them any more.

 

[murf]

according to the hornady manual, you are already two full grains over maximum. your muzzle velocity is 100 fps greater than theirs (test rifle uses a 24" barrel).

if your overall cartridge length is sticking the bullet into the lands, in addition to the overloaded round, i would expect you to have blown primers.

suggest you reduce the load a bunch.

murf

 

[mtnlvr]

if your overall cartridge length is sticking the bullet into the lands, in addition to the overloaded round, i would expect you to have blown primers.

I guess I'd expect to have issues if I were setting the bullet too close to the lands, but with the numbers I stated in my previous post, I'm 0.091" away from the lands.

I realize that every gun is different, but how can there be over 2 grains difference between two publications?

 

[243winxb]

Mysteries And Misconceptions Of The All-Important Primer

Article from an employee of CCI Mysteries And Misconceptions Of The All-Important Primer. http://www.shootingtimes.com/2011/01/04/ammunition_st_mamotaip_200909/

Most component primers have a little disk of paper between the anvil and the priming mix. Called the foil paper, it covers a priming pellet and is simply a manufacturing expediency. The anvil is omitted in this view for clarity.







Yes, those pesky little things we can’t do without are hard to come by at the moment. If this rush follows past trends, it too shall pass. Let’s talk about some of the lesser-known facts about primers while we fret about whether we have enough.





I suspect most readers know that a primer has more than one job. In addition to providing a spark to ignite propellant, it gives an initial boost in pressure to help the propellant reach a self-sustaining burn. It is also part of the case-sealing system that keeps hot gases behind the bullet and out of your face.





U.S. handloaders have a choice of primer size and purpose. There are separate versions for rifle and handgun; within each category, there are two sizes.





Size Matters
The first bit of useful trivia is that even though Small Rifle and Small Pistol primer pockets share the same depth specification, Large Rifle and Large Pistol primers do not. The standard pocket for a Large Pistol primer is somewhat shallower than its Large Rifle counterpart, specifically, 0.008 to 0.009 inch less.





A number of handloaders found this out when one of the “mega-magnum” handgun cartridges appeared a few years back. Original cases were formed for Large Pistol primers. Some reloaders decided to switch to Large Rifle primers to better handle the high pressures, and they found the rifle primers stood proud of the case head, an unpleasant situation in a high-recoil revolver cartridge.





Primer EquivalencyThere have been reams written about how various brands of primers compare. Tests to compare the effects of primer substitution have been published for years. I’ve been a lab rat long enough to understand that road is fraught with potholes.





We heard a number of requests to add a primer chart in the Speer manuals I wrote showing what the various primer makers call their primer types. Note that there are no such charts in my books. Why? First, switching primer brands from what we used in the manual could create an unsafe condition. Second is accuracy of information. One of the last Speer manuals before I took over printed a nice chart of primer sizes and manufacturers’ numbers. Almost before the first printing was sold out, one company completely changed its numbering system, and a foreign brand listed became unavailable. Hardcover books are almost like engraving stuff in stone, and I did not want a chart—that may be obsolete before the book ran its course—to create problems.





As for the “which is hotter/colder” discussion, a similar conundrum exists: primer specification change. CCI overhauled its entire primer line in 1989. We were careful to make certain that the new primers could share load data created with the older versions, but not every change is announced. Another time, shortly after a writer friend of mine had a lab shoot a complete series of rifle ammo with the only difference being the primers, another primer maker came up with a change that affected the outcome of that test.





Here’s a classic example of a printed mistake being taken as gospel: Another company’s reloading manual had a chart of primer numbers and types that incorrectly showed the CCI Benchrest primer as being interchangeable with the CCI Magnum primer. This was perpetuated over several editions of that manual before we convinced that company to correct it. People would call CCI and demand that our Benchrest primer was a Magnum because it was printed that way in another company’s manual.





Bottom line: If I publish a primer performance equivalency chart today, it will soon be obsolete, and some poor sod will try substituting primers based on invalid information. I apologize to the nice person who recently wrote my editor suggesting I do a handgun primer equivalency test, but it can lead to too much grief. Stick with published and current load recipes.





Magnum Primers: Use As Directed
Most primer makers offer a standard and a Magnum primer in each size and application. The Magnum primer offers more power for challenging ignition scenarios. A large-capacity case, a heavily deterred propellant, or extremely cold weather (less than 20 degrees Fahrenheit) typically makes the Magnum primer desirable.





There are two ways to make a Magnum primer—either use more of the standard chemical mix to provide a longer-burning flame or change the mix to one with more aggressive burn characteristics. Prior to 1989, CCI used the first option in Magnum Rifle primers. After that, we switched to a mix optimized for spherical propellants that produced a 24-percent increase in flame temperature and a 16-percent boost in gas volume.





Literature from some propellant manufactures often says that their products do not require Magnum primers. This is perceived as a good thing because Magnum primers are made in smaller quantities and require more chemicals; therefore, they are more expensive. However, I had to take a different view, one based on real-world issues.





We tested loads at both maximum normal pressures and at the starting loads (some labs calculate start loads—we shot them). Standard primers caused no ignition issues at the max load but posted higher extreme variations in pressure and velocity in the lower pressure regimes of the start loads. In extreme cases, the start loads produced short delayed firings—probably in the range of 20 to 40 milliseconds but detectible to an experienced ballistician. Switching that propellant to a Magnum primer smoothed out the performance across the useful range of charge weights and completely eliminated the delays.





If I’ve recommended a Magnum primer in reloading data I’ve developed, it’s because my lab results show it’s needed.





A Myth-Conception
Like others who reloaded in the 1950s and ’60s, I heard the old mantra, “CCI primer cups are hard.” I used CCI primers long before I dreamed I’d be working for the company, and I never had problems. I had talked to other hand-loaders who claimed to have had some trouble. Arriving at CCI/Speer in 1987, I found out the real story.





The metal cups were neither harder nor softer than any other brand. However, the early noncorrosive primer mixes that Dick Speer and Dr. Victor Jasitis developed had one difference from many other primer products at the time—the dried pellet was rather brittle. This was not a problem unless the loader tried seating primers too deeply; in that case the anvil was forced almost to the cup, and the brittle pellet broke away from the anvil. With little mix under the ti
p of the overseated anvil, a misfire was lurking. I decided the reason I never had a problem was that I seated off-press with hand tools that let me feel the seating.





The mix that did not like overseating was retired years before I arrived in Lewiston. It just goes to show how old perceptions can linger even in the face of data and facts.





Too Much Primer
You can have too much primer. When the output gas volume of the primer approaches that of the cartridge case, sometimes special handling is required. I remember when CCI was working with some experimental primers for 9mm Luger, and we started seeing odd time-pressure curves on the computer. Instead of the normal single peak, we saw two. One QA tech commented that it looked like the dual humps of a Bactrian camel.





It was a classic case of high gas volume but too little temperature. The primer’s extra gas unseated the bullet while still trying to light off the main charge, producing one peak. Then the bullet retarded as it engaged the rifling, creating the second peak. Although a shooter would never notice this in a production firearm, that double hump was worrisome, and we abandoned that mix.





We have a classic case study in the .22 Hornet. For years Speer used Small Rifle primers in the Hornet. When I shot some of the data for Speer Reloading Manual Number 12, I found too many propellants that were so rangy they would not meet my standards for publishable loads. As a result, we did not show very many propellants for the Hornet, and the velocities were rather modest.















While I was developing the .22 Hornet 33-grain TNT HP bullet, I tried Small Pistol primers, knowing from the 9mm experience above that such a light bullet could be unseated by primer power alone. I’d talked to a number of handloaders who were getting better accuracy with Small Pistol primers, and I wanted a look at the concept in a lab setting. Sure enough, switching to Small Pistol primers reduced the variations in pressure and velocity and also reduced average pressure. The latter let us safely run the charge weights a little higher for velocities more appropriate to the Hornet. Manual Number 14 shows many more Hornet loads with better velocities, thanks to Small Pistol primers.





Foiled Again
Most component primers have a little disk of paper between the anvil and the priming mix. There are many “campfire” rumors concerning this item. First, it’s called “foil paper,” not because it’s made of foil but because it replaces the true metal foil used to seal early percussion caps. (See the illustration on page 12.) The paper is chemically treated to burn ash-free.





The reason this little disk exists is strictly a manufacturing convenience. Wet primer pellets are smaller than the inside diameter of the cup when inserted and must be compacted to achieve their proper diameter and height. Without the foil paper, the wet mix would stick to the compaction pins and jam up the assembly process. The absorbent paper soaks up some of the moisture and binding agent from the wet mix and stays with the pellet when the pin is lifted at the end of the operation. It’s the same reason you put wax paper between hamburger patties—it prevents sticking.





Pre-Stressing Primers Does Not Apply
Occasionally, a person who has a bad experience with a dropped cartridge invokes the theory of primer pre-stressing. They are moving a civil engineering concept and practice to a technology where it does not apply.





The theory is that the act of seating a primer stresses the priming mix to the point where its chemistry is on the ragged edge of gross instability. Not so. Were this true, every cartridge dropped, regardless of how it lands, would discharge. Come on–thousands of cartridges get dropped each year, and few actually activate.





The real story is that Boxer primers leave the factory with the anvil higher than it would be when seated in a cartridge case. Seating so anvil legs touch the bottom of the pocket lets the anvil tip penetrate into the pellet of mix. The nearly universal recommendation of having the primer cup bottom 0.003 to 0.005 inch below flush with the case head exists to set the proper amount of priming mix between the cup and the anvil tip.





This critical distance is known as the bridge thickness. Establishing the optimum thickness through proper seating means the primer meets sensitivity specifications but does not create chemical instability. However, failing to set the bridge thickness through proper seating depth is the number one cause of primer failures to fire. The bridge thickness is too great with a high primer, even one whose anvil legs touch the bottom of the pocket.





I hope this helps you understand some of the more esoteric aspects of primers. They are amazing little gadgets, and few people fully realize the intricacies of their manufacture and use.

 

[243winxb]

Primers.

mtnlvr, i have personally had/seen defective primers. Remington large rifle primers 9 1/2, blew out for me, just like your primer photo. Thinking it was from high pressure in my 30-06, i lowered the powder charger. Primers stll ruptured. Light cast bullet loads in the 30-06 & 30-30, primer still vented. Defective Primers is what you have. Your primer has NO signs of pressure like- 1. "PRIMER LEAK"- The escape of gas between the primer cup and head of the cartridge case. 2. "PRIMER CRATERING"- A circumferential rearward flow of metal surrounding the indentation of a firing-pin in a fired primer cup. 3. "BLANKED PRIMER"- A fired primer cup in which the firing-pin indent has been punched out by internal gas pressure. 4. "BLOWN PRIMER"- A primer that is separated completely from the cartridge after firing due to severe expansion of the primer pocket and head. 5. "PIERCED PRIMER"- A fired primer which has been perforated by the firing-pin. The problem happens in all brands of primers. Pistol & Rifle.

 

[gamestalker]

That is deffinitely excessive pressure! That brass is toast.
Brass and primers no doubt function differently in this respect, but if your using good work up procedures, you'll be able to avoid excessive pressures that will eventually damage your firearms. I wouldn't personally blame the brass or primers, excessive pressure is the cultprit here. Look at the bolt face and head of the brass.
I load with Federal, Remington, and Winchester brass, but I always stick to one primer brand which is CCI 200's and 250's. I once punched a primer many years ago with IMR-4350 in my .270 Win. 700 action. My mistake was I didn't do a complete work up and started my load near max.. Once I backed off to just below mid data, I never had a repeat of that event, even when I loaded with different brass.
I don't think you can get enough IMR-4350 in the case to shear the lugs off, but you could certainly set the lugs & bolt face back, or damage the chamber. And if you continue blowing primers like that you'll likely succeed with one of the above issues.

 

[mtnlvr]

Hey 243winxb...good link on primers.

Unfortunately it's not 100% consensus on whether the root cause of this was a bad primer or over pressure.

I did work up loads from the starting load to max load twice, 5 stages of charge with 3 rounds of each. I never once saw any extreme flattened primers or noticed much if any change of bolt release force (although I could have paid more attention to this). So since I had great groups with the 60.5gr of IMR4350, I loaded up the 15 rounds of the Federal cases (which I received loaded in a baggie with the rifle, not sure if they were previously hand loaded) and 15 rounds of Winchester cases (once fired out of this rifle), all with the same load. The Winchesters got set to different COL varying from 2.800" to 2.883" (still .068" from the lands). Attached are the pics.

Do they appear to have been subjected to high pressure? I think any marks on the face of the Winchesters is a result of being fired after the blot face had been etched from the pinholed primers.

Thanks again for posting your thoughts. I'd really like to come to a definitive conclusion (if possible).

 

[30Cal]

I'm not surprised to see an FC headstamp--where you find loose primers, you will almost always find federal cases.

Dump the brass--your bolt is rapidly being rendered unserviceable. If that pimer/case head junction isn't supported by steel, it's going to leak worse and worse; even with good brass. Pretty expensive science project you've got going on.