6.5 x 55 PMC ammunition, case failure

[Beej]

I went to sight in a new scope yesterday on my 6.5 x 55 so fired a few factory rounds first, these were made by PMC. I noticed the third round i fired emitted a slightly different noise and when ejecting the cartridge i noticed the bottom 10mm of the case had separated from the rest of the cartridge. The primer seemed in relative good condition however so not sure if this is just bad brass or an overpressure situation. See photos .

Any ideas ?

Best wishes and happy Easter
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[weblyish]

Guess you're lucky it extracted ok

Would have been confusing and annoying if the front had stayed in the chamber and you jammed another in behind it

 

[Beej]

Guess you're lucky it extracted ok

Would have been confusing and annoying if the front had stayed in the chamber and you jammed another in behind it

yes for sure. I made sure i checked the barrel and mod were clear of any obstructions but was lucky

 

[Andyquadra]

Its been loaded to many times

 

[Beej]

Its been loaded to many times

Thanks. yes i had wondered that. definitely not a head space issue then ?

 

[Andyquadra]

Thanks. yes i had wondered that. definitely not a head space issue then ?

Have you got any pictures of some others fired and unfired?

 

[Will the chippy]

Are these brand new factory rounds?

 

[webley701]

Thanks. yes i had wondered that. definitely not a head space issue then ?

Your initial post mentions PMC factory ammunition but your third post quoted above implies that it may be reloaded.
Some clarification would be useful.

 

[SpikeD]

Looking at the 3rd photograph you can clearly see the classic stretch ring in the lower portion of the case, typical of repeated firing and full length re-sizing. It may be an artefact of the photo but looking at the headstamp by the "55" there is a semi circular pattern imprinted on the case head which can be a sign of high pressure. In photo 1 it looks like there's a crack in the brass on the shoulder so I'm doubting this is factory ammunition. Usually but not conclusively bad brass on factory rounds gives neck splits rather than head separation. If it was a headspace issue then I would expect you to see a lot more failures rather than just a one off or have you had more?

 

[Beej]

Your initial post mentions PMC factory ammunition but your third post quoted above implies that it may be reloaded.
Some clarification would be useful.

yes i had my suspicions that the ammo was reloads from a friend rather then factory ammo he said it was, but i didnt want to chat to him until i had got some opinions from others. I will take them back to him and ask if he had got them mixed up somehow and to dispose of them. Much appreciated.

 

[Beej]

Have you got any pictures of some others fired and unfired?

i havent but i have looked at one of the other fired cases and noticed a slight ring in the exact same place. No other marks on the shoulder or back the case though.

 

[Andyquadra]

i havent but i have looked at one of the other fired cases and noticed a slight ring in the exact same place. No other marks on the shoulder or back the case though.

Straighten out a paperclip and make a small 90 degree at one end. Use it to see if yiu can feel the ring on the inside of the case

 

[jthyttin]

yes i had my suspicions that the ammo was reloads

You'd been better off communicating this from the start. The failure mode is quite different for brand new ammo and reloads (of unknown origin).

Looking at your first post, I started wondering if the brass had been weakened either from outside (some chemicals etc) or inside (contaminated powder or something). Or some very weird issue with chamber, combined with grossly undersized brass (re: headspace) and probably too brittle also.

 

[Rusty Gate]

I went to sight in a new scope yesterday on my 6.5 x 55 so fired a few factory rounds first, these were made by PMC. I noticed the third round i fired emitted a slightly different noise and when ejecting the cartridge i noticed the bottom 10mm of the case had separated from the rest of the cartridge. The primer seemed in relative good condition however so not sure if this is just bad brass or an overpressure situation. See photos .

Any ideas ?

Best wishes and happy Easter
B
BView attachment 416636 View attachment 416637 View attachment 416638

Shoulders to case & neck junction in a mess to

 

[Sinistral]

yes i had my suspicions that the ammo was reloads from a friend rather then factory ammo he said it was, but i didnt want to chat to him until i had got some opinions from others. I will take them back to him and ask if he had got them mixed up somehow and to dispose of them. Much appreciated.

PMC have been out of the sporting rifle ammunition business for many years. The last 6.5x55 140gr SP I can find appears in their 2005 Catalogue. The catalogues after that show they had switched over to volume production of military small arms calibres in .223,.308, 7.62x39,.50 BMG.
It would be interesting to see a pic of the box these rounds came from.