Cause of primers exploding?

[Blacktails365]

Had this happen on two rounds out of a factory Rem box. Resulted in blowback into the magwell.
What causes this and can it damage a rifle?

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[oli700]

need way more details......no one knows if your talking about primers spontaneously combusting or primers falling out of the brass upon firing , or cratering the cup, blowing the cup off .....

 

[Jeedia]

Is this a rifle or pistol?

 

[Open_Wire]

Usually impact...

 

[Steve M]

It sounds like you are having primers rupture. Leading causes include over pressure ammo, thin primer cups, firing pin to long, firing pin to pointy, firing pin spring too strong, or the hole in the bolt face for the firing pin to pass through is too large. A visit to a competent gunsmith will help sort out any problems that may be caused by the firearm.

 

[Blacktails365]

Sorry. This is a model 700 sendero in 22-250. Upon firing the rifle im getting blowback and (wish I could post a photo) the primer discinagrated.
Smoke came back into mag well.
I don't recall where I got the ammo but suspect it came with a rifle purchase some time back

 

[ZA_Survivalist]

I had WAY overloaded .308 someone said was "surplus" a while back.
Loaded so hot it would eject the primers into the action of my semi autos I had at the time exactly how you described. At first I thought it was a firing pin issue but after I tried in in a few different rifles I knew it was the ammo.

Yours being factory ammo, thats a tough one. Any other ammo you've tried in that rifle?

 

[edzz]

If the ammo "may" have come with the rifle how certain are you that these are factory loads? Many people use factory boxes to store their reloads in.

 

[Blacktails365]

It could be someone's reloads but I usually try to avoid those. It looks like factory but not new factory.
So it sounds like caused could be overloaded rounds or bad primer or bad firing pin.
Last question is can it damage a rifle?

 

[Pete F]

It could be someone's reloads but I usually try to avoid those. It looks like factory but not new factory.
So it sounds like caused could be overloaded rounds or bad primer or bad firing pin.
Last question is can it damage a rifle?

Yes, overpressure rounds can do significant damage and could ruin your barrel and bolt. Dump the powder out of one and weigh it. Then check against a reloading manual for type of powder - ball, extruded, flake etc. Also, the primers may be magnum, which would add to the overpressure. The bullets may be over crimped too.

 

[Blacktails365]

Never thought about the possibility of magnum primers.

Thank you all for your help

 

[CLT65]

Pierced primers can etch your bolt face, assuming it's just soft primers or a damaged firing pin. A gross overload is another matter.

I would look closely at the firing pin for any sign of damage, and if there is none, get some fresh ammo and see how it does.

 

[DizzyJ]

Sorry. This is a model 700 sendero in 22-250. Upon firing the rifle im getting blowback and (wish I could post a photo) the primer discinagrated.
Smoke came back into mag well.
I don't recall where I got the ammo but suspect it came with a rifle purchase some time back

Stop using that ammo. It's either loaded too hot, too sharp of a firing pin, or too much clearance between the firing pin and firing pin channel.

 

[Blacktails365]

I stopped. Not something I care to experience again. Since half the box and other ammo worked fine I'm thinking it must not be the firing pin.
Thanks for your reply

 

[Member 5605]

Please post photos, they are worth a thousand words.

 

[Blacktails365]

 

[Hayshaker]

I would either throw all of them away or pull the bullets and start with YOUR powder and loads. my suggestion as that caliber of brass is not usually plentiful

 

[CLT65]

Wow, ouch. I was expecting leaking or pierced primer. That one is blown out! Definitely a good call to stop using that ammo. I would pull it down for components.

 

[bbbass]

Sorry. This is a model 700 sendero in 22-250. Upon firing the rifle im getting blowback and (wish I could post a photo) the primer discinagrated.
Smoke came back into mag well.
I don't recall where I got the ammo but suspect it came with a rifle purchase some time back

Yikes!! Reloads or a rare factory mistake. At any rate, 22-250 is already hot stuff, doesn't need any extra poop!!

If the ammo "may" have come with the rifle how certain are you that these are factory loads? Many people use factory boxes to store their reloads in.

^^^this

Last question is can it damage a rifle?

Yup, examine the bolt face and nearby parts carefully. I had a used Weatherby 300 that I bought that had a cratered bolt face I hadn't seen and did just what your pic showed. I demanded my money back!!!

 

[Member 5605]

I'm curious if you should check your headspace. That's where you could have an issue.

It would be nice to measure the fired brass' headspace from the datum line and compare to SAMMI specs.