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Blown out primer!

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Category: Reloading
Forum Name: Reloading .303 British
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Topic: Blown out primer!
Posted By: Zed
Subject: Blown out primer!
Date Posted: November 11 2013 at 3:21am
Gent's, I would like your opinions on possible cause of a minor blow out around the primer of one case in a batch of 50 (reloaded) Please see attached photo.

I am thinking of the following possibles:
1:The case may be too loose around the primer
2:The primer is faulty, or possibly got a Pistol primer by mistake.
It appears to have left a slight mark on the bolt head, which is not great. I will be removing primer to examine it, then scrapping the case obviously; but am curious to know if anyone else has had this happen.
Thanks, Zed.


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It's nice to be important, but it's more important to be nice!



Replies:
Posted By: Shamu
Date Posted: November 11 2013 at 5:44am
A guess.
As the edge of that one primer seems more flattened than all the others, so I'm going with a Large Pistol primer blew out under rifle pressures?


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Don't shoot till you see the whites of their thighs. (Unofficial motto of the Royal Air Force)


Posted By: Ed Hill
Date Posted: November 11 2013 at 10:13am
It looks flatter tag the others, as Shamu noted. I'd agree improper primer
or a loose fit in the case.

Ed


Posted By: LE Owner
Date Posted: November 11 2013 at 1:22pm
Could just be the lighting but quite a few of those expended primers look oddly misshapen.
A couple of the cartridge case bases look dished as well.
At least one other primer shows a pinched or dented spot on the rim that looks much like the spot where the other primer blew out.
I'm figuring defective primers, damaged during manufacture of the cup.
Like I say it may just be the angle of the light, but I'd observe carefully how the de capping procedure feels. Look for loose pockets.
 
A fellow on another board has been having problems with loosely fitting primers in another caliber.
Could be a bad lot of primer cups.
 
WW1 era Remington ammo had a problem with blown primers when used by the French in the Lewis guns mounted on aircraft. They took to breaking down the cartridges and heavily staking the primers in, then reloaded them.
IIRC the problem was traced to undersized primer cups from a subcontractor.
 
When I first began reloading the .303 I used Seller & Bellot cases. I found these had such a tight primer pocket that many primers detonated while being seated. I had to ream out the pockets to get them to work.
I've heard that's no longer an issue with S&B .303 cases, but it suggests that some European Boxer primers may be a tad small for American made cases.


Posted By: Shamu
Date Posted: November 11 2013 at 9:13pm
S&B has earned a poor reputation IMO.


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Don't shoot till you see the whites of their thighs. (Unofficial motto of the Royal Air Force)


Posted By: Zed
Date Posted: November 12 2013 at 4:08am
Thank you for your comments gentlemen; I will inspect it next weekend. I remove the primers by hand in a so I will look out for ones that are too easy to remove and maybe retire those cases. I do not use a reamer as they are always de-primed prior to cleaning in an ultra sound bath. It is possible that pistol primer got mixed in with the rifle primers when swapping the rig from .45ACP to .303 British. I tend to be very careful to avoid these type of errors, it would be an easy thing to miss.

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It's nice to be important, but it's more important to be nice!


Posted By: petes
Date Posted: November 16 2013 at 9:49pm
My guess is loose fit in case for what it is worth.


Posted By: Zed
Date Posted: January 12 2014 at 3:38am
Just to update on this blown primer. The primer did not seem loose when removing it; which was a surprise. But When I inspected the case with a magnifying glass  I could see a scrape in the side of the primer well; I suspect this was the root cause of the leakage. Anyway, I've binned that case.

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It's nice to be important, but it's more important to be nice!


Posted By: CTB
Date Posted: September 18 2014 at 7:24pm
Originally posted by Zed Zed wrote:

Just to update on this blown primer. The primer did not seem loose when removing it; which was a surprise. But When I inspected the case with a magnifying glass  I could see a scrape in the side of the primer well; I suspect this was the root cause of the leakage. Anyway, I've binned that case.

Hallo , 

i seen  this post only today ( 'cause i'm a newby ) but i have to tell

 ....the same identical  thing happened to me the past year with my LB n.4
Case Remington - Powder 4064 ( 39,8 grs ) - Bullet Sierra MK HPBT 174 grs
OAL 78 mm ( then not remarkable chamber pressure ) but  ...primer Winchester

Well ,  usually i utilize Federal 210GM but at that time my supplier do not have then i 
took Winchester )

when i primed the cases ( i utilize e manual RCBS primer )  i felt a insert strenght
"too soft"   ( i never felt it with the Federal 210 )  - well , after twenty shots , on
cleaning the gun , i seen a little mark on the front of the bolthed  -  i gone to inspect
the case with the magnifier and seen the primer drilled and a little portion ( 1/2 mm )
of the angle of the primer pocket not only scraped , but "melted"  justlike by a microtorch

never seen anything like this ( ...somewhere i have some pic )Confused

....i stopped the utilize of these primers 

a month ago i  thought i would re-use  them with the 8x57 IS crtg 

wery mild load and   ....again ( but without "melting" ) - 

then    .....a clue is not a evidence  but two  ! ! Shocked

my personal opinion it is the composition of the primers cups alloy  it is not well balanced
to resist well to a "overheating"/"overpressure" ( especially if the priming compound quantity 
it is not  exactely / perfectly distributed )


CC






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nec aspera terrent


Posted By: Zed
Date Posted: September 20 2014 at 12:58am
I have also changed to the Federal primers instead of Winchester, which was used in this case.

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It's nice to be important, but it's more important to be nice!


Posted By: CTB
Date Posted: September 20 2014 at 4:52am
...correct solution of the problem Approve

i seen from a mile ,  in your pic ,  the Winchester primers Smile

CC


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nec aspera terrent


Posted By: Toten Kopf
Date Posted: September 21 2014 at 11:07pm
I have had this happen as well.  .308 case fired in a Remington SPS Tactical.
 
Winchester Large Rifle Primer.  Only once after thousands and thousands of Winchecter primers.
I still have many, many WLR primers and will continue to use them.  Perhaps some LP primers got mixed up with the manufacture of LR primers or thin LR primer cup.  Who knows?
 


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"It Takes A Strong Man To Be Kind", Sgt Nathan Wilson, 5th SFG (1970)



Posted By: CTB
Date Posted: September 22 2014 at 3:43pm
hi guys

to continue studying about it  ......

could it be a matter of primer seating depth ?    ...better ,  
too much ( ...or not enough ) force applied in "squeezing the priming compound" 
at the moment of priming the case ?   ....then a irregular compound ignition on a 
also irregular  cup deformation ? 
....even if hardly  , in manually priming , you can apply always the same identical 
force   (...and i think the Winchester's engineers should know )

or more simply  ...a cups production defect that sometime happen ? 

CC


  


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nec aspera terrent


Posted By: Zed
Date Posted: September 23 2014 at 8:27pm
It is possible if a primer is not quite aligned it will scratch the side of the case well and create a small gap that is exploited by the combustion pressure and leaking the gases.
Initially when using the Dillon 650 loading rig I would have the primer get pushed in sideways on; this I resolved after going through the rig and making a few adjustments. Firstly the detent spring that holds the ball bearing for the rotating plate is too long and when the plate turns to the next position it would snap into place, also causing powder to shake out of the cases when doing .45 's. The plate needs to be well lubricated underneath and have no up/down play while remaining easy to turn by hand. Not shaking the rig too much on end of travel also is important. Adding strong elastic bands to return the powder hopper also helped improve powder dosage tolerances.


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It's nice to be important, but it's more important to be nice!


Posted By: W.R.Buchanan
Date Posted: October 19 2014 at 1:25pm
Zed: I just had my first blown primer in 40+ years of reloading.  Luckily it was in my Ruger Guide gun which is not only new but really strong as  well. 
 
Your primer blow out was a relatively minor one. My blow up was a little more severe than yours.
 
All of that primer (no longer in the picture above) and resulting debris exited the gun thru the relief hole on the side of the gun.
 
Needless to say this scared the livin' ship out of me!
 
It took a while to actually figure out why this happened and the result was a loose primer pocket.
 
This was once fired Federal .30-06 brass but still there were 7 more loose pockets in that batch I found and I ended up measuring every single one. I also pulled 50 more loaded rounds only to find 3 more loose ones.
 
I had seated all of these primers on the machine, which was a deviation from my normal method of using a hand held RCBS Universal Priming Tool.  The advantage of the hand held tool is that you can feel the pressure needed for each one as you are doing it. With the loading press ,,, Not so much.
 
So my caution is that if a primer takes little pressure to insert,,, the case is probably bad. It should go in with a firm press fit.
 
The primer pocket should measure .211-.212 +.000  This one now measures .251! Boom!
 
Randy


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It's not how well you do what you know how to do,,, It's how well you do what you DON'T know how to do.


Posted By: CTB
Date Posted: October 20 2014 at 8:42am
Hi gents 

i found the photo of the same "adventure" happened to me some months ago
with primers WLR     ....as i told in a precedent post 

red  = the hole in the cup
green =  the "melted" surfaces






 .....i continue to utilize the bolthead    Wink,      ...no more  the Winchester primers  Thumbs Down

CC



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nec aspera terrent


Posted By: Zed
Date Posted: October 22 2014 at 11:33am
I also had a very slight mark on the bolt head face after the blown primer. Continued to use it without issue, but have now find a bolt head of higher number to correct the headspace which was on the upper limit.

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It's nice to be important, but it's more important to be nice!


Posted By: Gun Nut 4
Date Posted: December 18 2015 at 4:12am
I picked up a bunch of R-P cases once, I had one devil of a time de-priming them, their  flash-holes were too small for the de-priming pin. It maybe that this particular case had a smaller flash-hole than the rest of them. Was there any problem de-priming it?

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Gun Nut 4


Posted By: Zed
Date Posted: December 18 2015 at 4:17am
I use a home made de-primer, as I remove the primers before cleaning and preparing the cases. However there are times when the primer resistance to push out is different. In the case of the blown primer, I did find evidence of damage to the pocket, which I believe was the cause. Not had any issues since.


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It's nice to be important, but it's more important to be nice!


Posted By: Gun Nut 4
Date Posted: December 18 2015 at 4:31am
Having read a few more comments, I see it was a head-space problem. I almost asked if you were noticing any blackening of the cartridge neck. I'm glad you were able to isolate the problem and correct it. Those good old No.4 Mark I bolt-heads, they are enough to keep me leaning towards the Mark III's and the Pattern 1914's, in spite of the large variances in their bore diameters. They shoot find if you can match the bullet to the particular bore diameter, and a lot better than having a case-head separation while in the field, without having the tool to remove the fractured brass.

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Gun Nut 4


Posted By: Zed
Date Posted: December 18 2015 at 9:35am
Luckily I've never had a case separation during a competition; but I do have the extractor and it's always within reach if I need it. That said; I'm more attentive of the case condition now and inspect each one after cleaning. As soon as the "ring of death" starts to show around the base; they are junk. Once you've got the eye for it; it's easy to spot.
Regarding the headspace; I have since bought some proper gauges and it was good on the field gauge at 0,074" but just failed the no-Go at 0,70". It now passes both of these with ease.


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It's nice to be important, but it's more important to be nice!


Posted By: W.R.Buchanan
Date Posted: December 18 2015 at 9:54am
I have had exactly one blown primer in my life and it happened to me last year and scared the pooh out of me.
 
It was a .30-06 round loaded in a once fired Federal Case. an 85-90% load.  It happened in my Ruger Guide Gun which had less than 50 rounds thru it at the time. I had to open the bolt with a plastic mallet, and after several of us inspected the gun we deemed no problem and I continued to shoot with no further incident.
 
However I did start a different box of ammo as I was now not sure of that batch.
 
The Primer Pocket was .250 after firing IE: it was destroyed, and the primer and all debris went right out the vent hole.
 
When I got home I pulled all the remaining bullets and pushed the primers out and found three out of the 30 or so left had loose primer pockets and the primers pushed out easily. I used a Lee Depriming Punch and Base and a small Sinclair Arbor Press to do this.
 
After measuring those 3 I found them to be nearly .211 and since the WLR Primers I was using measure .2105 that could have been the part of the problem.  Primers do swell when fired and most of the fired ones on the floor are nearly .212 so I wasn't sure exactly what was going on.
 
My remedy was to run all of my Once Fired Federal Brass, all of which was used to test fire Rebuilt Garands, thru a Dillon Primer Pocket Swager.
 
It is common machine shop practice when you ream a hole and it comes out big, to put a ball bearing over the hole and smack it.  The result is the ball swages the entrance of the hole down a little.
 
The Dillon Tool does essentially the same thing when it radiuses the mouth of the pocket.
 
The other thing I did was stop using the priming function on the PW Metal Matic II press I was using as it provided no feel as to how much pressure was required to seat the primer.  I use an RCBS Lever type tool now and it is the best priming tool I ever used.  I can do 50 cases in 3 minutes easy and feel the pressure on every single one.
 
After swaging the pockets on my brass I have not had any primers push in with light pressure, and needless to say no more blow ups..
 
Randy
 


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It's not how well you do what you know how to do,,, It's how well you do what you DON'T know how to do.


Posted By: pogson
Date Posted: July 12 2018 at 6:38am
There's lots of good information here. I'll add a bit of mine...

One thing that has not been mentioned is that high pressures can weaken cases and upon repeated firings things can go wrong: split necks, body ruptures, head separation and primer pocket enlargement. Keep pressures down to the level you need rather than maximum. For hunting, when I know I don't need maximum range, I reduce charges a few grains to give longer case-life. I have some cases I've been firing since the 1970s.

Even if charges are set within safe limits there is another way things can go wrong, powder bridging. The stick powders particularly can jam up in the powder measure and dump an incomplete load in one case and an excessive load in the next case. These days, with an electronic powder scale, I weigh each charge. This also benefits accuracy because my measure, with my best powders, throws charges +/- 0.5 grains. A powder bridge can greatly exceed that variation. In the worst cases I've had a thrown charge fill a case to overflowing. I've long inspected my charges by peering into each charged case with a small flashlight or inserting a rod into the charged case to check the level of the powder. Now, with the fast electronic scales, I just weigh each one. Groups are smaller. Deer are just as dead.

303 British has not nearly as high a pressure as other cartridges like .308 or .30-'06, so seeing cratered primers and flattened primers suggests some of these pictures are showing loads far too "hot". On the other hand, very light charges can sometimes detonate or show pressure spikes. That's why reloading manuals show starting loads higher than expected for some powders. Many powders don't burn reliably at lower pressures as might be found near starting loads in 303. Some manuals start automatically 10%, 5% or 3% below maximum. I would not use 10% low with any slower powder like 4350 in 303. It might be OK with 3031 to 4895. For hunting I generally work 1 or 2 grains below maximum because I want to keep my cases longer and I know my trajectory will reach out and touch deer effectively as far as I can see them in my usual spots.


Posted By: W.R.Buchanan
Date Posted: July 13 2018 at 10:41am
The secret to long case life in the .303 is to only neck size the brass. 

 I use a Lee Collet Style Neck Sizing Die, about $15 from Titan Reloading or a dealer near you.

My gun has one of the "generously" sized chambers we all know about, and it moves the shoulder of the case forward about .060+ It also reshapes the shoulder to something about .060 long and at a 45 degree angle. Good thing the case headspaces on the rim cuz there ain't much shoulder.

Pushing it back to original with a F/L die only makes the case separate on the second or third firing. 

The good brass out there is PPU as far as I can tell.

Randy


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It's not how well you do what you know how to do,,, It's how well you do what you DON'T know how to do.


Posted By: Stanforth
Date Posted: July 13 2018 at 2:38pm
I have experienced similar faults in one of my Remington Rolling Block rifles, 7X57 Mauser.
 
In all cases it was with Winchester cases. Never any other make. I binned all my 7X57 Winchester cases which was distressing as that calibre is ultra hard to find in the UK.
 
No more problems.


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Life.. a sexually transmitted condition that is invariably fatal.



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