Winchester WLR primer issues

[vintage hunter]

Anyone had problems with the cups burning through with Winchester WLR primers? I've had this happen 4 times here lately with 2 different rifles and calibers. First off a week or so ago with an Arisaka T38 and twice today with my M1A. Blamed it on old cases with the T38 to begin with but after it happened today with once fired 7.62mm NATO cases I took a closer look. The gas isn't leaking between primer and case as I assumed, it's actually burning a small hole through the cup right in the corner radius where the cup folds to form a bottom. All primers are from the same batch purchased in 11-13. Looked for a lot number on the carton and didn't see anything marked as such. I hate to think this is a bad lot but don't know of any other explanation for the issues I'm having. Any thoughts?

Information

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[browningautorifle]

I use those very primers and can't say I've had problems. My primers are quite likely older though...by a couple years.

I've seen it but on old Remington #6 or some such thing. Very old primers. Burned craters in the face of my M4gery bolt.

[Parashooter]

This is a known problem with some lots of WLR primers from a couple years ago. Reports are that Winchester will replace them. Google "WLR primer problem".


Typical consumer image showing defect.

[Bruce_in_Oz]

If the primers are showing "burn-through" at the circumference of the cup, it is most likely excessive work-hardening of the brass cup.

When primers "leak" or "blow-through" where the striker indent is, start looking at one of several things:

1. Excessive striker protrusion "over-stretching" the primer cup.

2. If the striker "indent" is completely or partially blown out, check VERY carefully for an oversized striker hole AND/OR an undersized (diameter) striker.

3. If the "blowout" is within the indent, inspect the tip of the striker. This is VERY important. ONE rupture will release a high-velocity jet of very hot, high-pressure gas back against the tip of the striker. This "jet" acts like a tiny plasma cutter and "eats" a little chunk out of the tip of the striker. This significantly "roughens up" the striker, making it almost inevitable that the next primer will "fail" because of the sharp edges and uneven shape of the "damaged" striker. Thus, MORE burning. Once you lose a "chunk" of the side of the tip, "blowback" from the increasingly damaged primers will start to eat the striker hole, which in turn will allow more nasty deformation of the striker indent, MORE "over-working" of the cup, and MORE blow-outs and bolt / striker damage. Things will go BAD very quickly.

The specified diameter, condition and profile of the striker tip AND striker hole, as well as the "Min / Max" gauging for protrusion; are vital and "intertwined".

This applies whether you are driving a .22 Hornet or a “Ma Deuce”.

[Bruce_in_Oz]

I should add:

When a primer blows out like the one shown. look for "mushrooming" of the primer. This will indicate that the pressure within the primer caused it to "flow" into the primer pocket chamfer.

Too much chamfer will allow too much "flow" and thus a work-hardening induced failure. A reasonable and smoothly radiused chamfer will support a primer operating at "normal" pressures.

The final thing to consider is this:

If the primer pocket is a bit tight / rough and especially full of crud (case being many times loaded and the pocket accumulating "residue"), cup is "stressed" during seating, due to poor alignment of priming tool,etc., the potential for a primer "mishap" rises sharply.

Inspect your cases.

Clean and "de-burr" the pockets.

Run a "uniforming" tool through the primer pockets of new / once-fired cases.

If the primer "seating" operation "feels funny", stop, set that one aside and investigate carefully later. DO NOT "break the rhythm" by being too distracted when reloading.

Case preparation is just another important, if at times tedious, facet of "happy reloading"

Dodgy ammo may damage your toys and, if taken to extreme, may damage YOU.

[Gun Surfer]

CCI 41 failure thread posted over at AR15 on 3/16. Thread linked below, but in case you cannot see the pics, I included one. In another pic of his bolt face, it put a dimple where the failure occurred. (Another guy posted a pic of a bolt with dimples in a ring all round where primer pocket was located, supposedly caused by CCI 200s in that case.)

Does this pic familiar? Some of the speculation over there is on a hot 600yd load, or bad primer pockets / poor pocket prep. I use lots of Win LR never had this issue, or ever on any reload and hope I never do.

CCI 41 primer failure. - AR15.COM

[CINDERS]

That would do wonders to the bolt face a mini gas axe......

[browningautorifle]

a mini gas axe

That's exactly what they did. I used these older primers (Rem) along with new CCI 400s and the only difference in the reaction to firing was the old ones had holes in them. Small craters around the bolt face...it still sold at the next gun show. Guess some guys don't care.

[vintage hunter]

Small craters around the bolt face

Did'nt notice any cratering on the Arisaka bolt face but one of the failures sure left one in the M1A bolt face. Wish it would've been the other way round, T38 bolts are a dime a dozen but G.I. M-14 bolts are a fair bit harder to come by.

older primers (Rem)

Have'nt had an any troubles with Remington primers in component form but I did have problems with some older Remington factory loads where the primers failed. One(25-06) gouged a ring all the way round the bolt face of a custom built Mauser 98 and the other(6mm rem.) completely blew out from the looks of things and wrecked a nice late 60's Remington 700 varmint special.

[browningautorifle]

Not a chop against Remington, the primers I had were probably near as old as I am. Parts of me don't work so well any more either...