Primer Wow

[JRLSH]

Never had this happen before and was wondering if any of you guys(or girls ) had had this happen to you. I was out shooting yesterday, enjoying the sun and some new loads I had made up. I was inspecting each of the rounds after each shot and discovered this one after one of the shots. The sound was the same as all the others and didn't appear to be any different in any way, except when I looked at the case this is what I saw. I have shot this same load(powder, bullet, case, etc.) several times without incident. Was this a bad primer? Bad case? Any help at all would be appreciated. The load was on the starter end of powder and nowhere near the max load. Was thinking I might be on the low side of low as I shot some with more powder than these without any incident like this( ie.too much pressure?). Also look at the bolt face. It caused a dimple in the face of the bolt as well. Should I continue to shoot with this or should I replace the bolt? I fired 2 more rounds after this one without incident but felt like I should stop and get more info before continuing. Needless to say, it was a WTH moment.

 

[snuffy]

Impossible to tell, since you didn't list----the firearm involved, the load, your loading technique?

It looks like the edge of the prime let loose. Another picture of that case with the primer removed,(decapped), would give more info.

It looks like a LC-08 case, did you remove the primer crimp before seating a new primer? Failure to do that could deform the primer enough to allow it to leak when fired.

I'm through guessing, more info please!

 

[JRLSH]

Yep, my bad

Snuffy, (et al), I was just thinking that. I didn't give enough info about the rifle and all. It is a Bushmaster bolt gun. Case was FLS, primer pocket reamed(primer pocket uniforming tool from K&M) and seated with a CCI#35 primer and loaded with Lee dies on a single stage press. I am very meticulous in my methods(cleanliness, measure twice, measure each powder charge/load on a scale, and yes, I do remove the crimp( or at least try to) on all LC cases. Sorry for the spotty info. Also, it is a LC08 case and was loaded with 210gr of WC860 with a 650 gr M33 ball bullet.

 

[JRLSH]

Pics of deprimed case/ primer

Snuffy/et al...
What say you? Looks like maybe not all of the crimp was removed. But I don't know.

 

[snuffy]

That's better, but-----what bullet, powder, charge weight? .223?

You used a primer pocket uniformer? That tool does NOT remove the primer pocket crimp. It simply makes sure the bottom of the primer pocket is square and flat. You either have to swage the crimp, or cut it. There's crimp cutting tools available from several makers, I use the one from Hornady.

http://www.midwayusa.com/product/501588/hornady-primer-pocket-reamer-tool-small

RCBS makes a swage that goes in a press, but only works with a rockchucker. The holy grail is the Dillon super swage.

http://www.midwayusa.com/product/235832/rcbs-primer-pocket-swager-combo-2

 

[snuffy]

Yup, see post #5, I was typing while you were.

The edge of the primer cup caught the edge of the crimp that was NOT removed, tore the primer cup so it lost it's seal on the side of the primer cup. Primers inflate like a balloon against the sides of the pocket when the shell is firing. The edges are like a gasket to keep hot gases from getting loose. The fact that there's a divot in the bolt face tells you just how hot those gases are. Like a cutting torch.

Get a crimp removing tool. Do NOT use a drill, or a case mouth chamfer tool, as this usually takes too much metal away from the edge of the pocket. Besides, there's no "stop" built into it like the Hornady tool I listed.

 

[243winxb]

Gas leaking between the brass and primer, loose primer pocket. Or at times a defective primer cup. Both will result in the same bolt face damage. In photo albums here. http://www.photobucket.com/joe1944usa Any primer can be defective. Mine were Rem 9 1/2. Pressure made no difference on when the defective cup would blow out.

 

[JRLSH]

Thanks all

Many many thanks to you guys. But one more question....what about the bolt face? That little dimple really bugs me and freaks me out as to whether or not to keep shooting with it there. Think it will make a difference?

 

[243winxb]

Bolt face is fine, not a problem.

 

[HiBC]

I take it you are loading 50 BMG,given the bullet weight and powder charge.

Be sureyou do nothing to the walls of your primer pocket,in other words,don't cut in a gas leak.

I have no experience loading 50 BMG

If the crimp is catching an edge of the cup going in,and is being forced,could maybe cause some problem.

Do you have the means to measure and control how much you set the shoulder back when you resize?Are you bumping the shellholder off the die?
If so,you can create a condition resembling excessive headspace by setting the case shoulder back.
On firing,cartridge is driven fwd by the firing pin.The case obturates and grips the chamber walls.If there is clearance between primer and the bolt face,the primer can blow back to the bolt face.

Seems like I heard there is something about using a dial indicator or gage of some kind to control primer seating on the 50.

You are in a tough spot,the ammo stuff is expensive,but,that hot gas sure cuts steel fast.

So,how do you feel about shooting glasses,seeing what a little gas does to steel?

 

[snuffy]

Good Gawd, the 50 BMG? See why I said not enough info? Camera pics with nothing to gauge size by, those pics looked like a .223 case head.

Nope, no experience loading the ma-duce, well the ammo anyway. I don't know if Hornady makes a primer crimp reamer, or lee. Lee makes 50 BMG dies, and a press to load them, but I don't know how or if---------!! LE wilson has one that's made to go in their case trimmer that will take that primer crimp out.

http://www.midwayusa.com/product/926654/le-wilson-case-trimmer-50-bmg-primer-pocket-reamer

I had to assume, now see the real meaning of ass-u-me, made an ass out of u and me.

 

[chiefr]

I have at times overswaged the primer crimp before when preparing mil brass. This has resulted in a slightly oversized primer pocket resulting in the primer pushing outward when fired.

If the primer seats exceptionally easy, I will discard the brass. Years ago I switched from an RCBS swager to the Dillion because the Dillion was much faster. Buggered up a few primer pockets before I got the hang of it.