Has anyone seen this?

[outdoorguy2000]

I'm trying to identify the cause of the bottle neck expanding and straitening on this shell case? When it happened, it sounded and felt as if my Garand fired two rounds from one squeeze of the trigger. The second report was much louder than normal and the rifle did not go back into battery.

I think it fired without the round being fully chambered. I just don't know, it happened so quickly.

It hasn't happened again and I have had no further malfunctions.

Thanks in advance for your feedback.

[RDS]

A similar thing happens when a 7.62 Nato (.308) is fired in 30-06 chamber.

[RCS]

looks like what Rich stated, 7,62mm fired in a 30-06 chamber, if the case was fired out of battery, you would see more case damage and possible rifle damage.

But anything is possible

[outdoorguy2000]

RDS & RCS thanks for your response. The round was 30-06 surplus purchased from the CMP. I also thought things could have gone much worse if it fired out of battery. I'm baffled as to what happened.

[TJT]

Show us a pic of the head stamp. Agreed, looks like a .308 fired in an '06 chamber. Doesn't matter that it came from CMP--
they're not infallible and stuff happens.
Jon

[outdoorguy2000]

This is the best I can do for a picture. It is stamped HXP and appears to be dated in 76. There also appears to be a slight crease on the case head above the date stamp.

[Jersey Devil]

Greece did produce HXP in both .30 caliber and 7.62mm NATO, so I think perhaps an HXP 7.62mm NATO round got mixed in with your HXP .30 caliber ammo.

[RDS]

Check the rest of the ammo from this lot and make sure there is no 7.62 Nato mixed in. If it fired that far out of battery the case would have swollen and chances case head would have blown or ruptured. Very odd.

[RDS]

Can you post a photo of the case alongside of a fired 30-06 and fired 7.62 Nato case.

[outdoorguy2000]

I don't have any 7.62, but here is a side by side of the bulged shell casing and a normal shell casing. I did find an example of a 7.62 fired out of a M-1 on line and posted it next to my photo.

[RDS]

I am stumped. Sure looks like a 30-06 blown out case. There is only one other possibility I can think of. Check your chamber very carefully. If possible do a chamber cast. Also check headspace. The possibility I am thinking about is the chamber was modified to 7.62 Nato with a chamber spacer and it was removed.

[outdoorguy2000]

It is also a CMP Garand and came with specs indicating they were all within acceptable ranges. I understand as TJT previously indicated that the CMP is not infallible. I think if the chamber was way out of spec, other shell casings would look similar. I put several hundred rounds through it without incident prior to this happening and at least another 50 since, all without incident.

I'm including another picture of the shell casing showing that it is concave at the mouth. I wonder if the round discharged while the bullet was partially seated. Thanks for all the help. This is starting to make me nuts.

[RCS]

just a guess, but could that blown-out 30-06 case have been a reduced charge ? I have fire formed cartridge cases to other case dimensions including the shoulder and case mouth. A reduced charge and a bullet is required without damage to the case (sometimes cornmeal helps with the space) and out of battery fire would cause the loud report

[outdoorguy2000]

RCS, you may be on to something with your explanation. I never thought about a reduced charge before, but I have figured the discharge occurred out of battery. That would explain why the case bulged without rupturing and it not being fully chambered would make it sound louder even with a reduced charge. You have a plausible theory. Thanks!

[RCS]

really long odds of both a reduced load and out of battery firing at the same time

[outdoorguy2000]

Yep, but no one seems to have a better explanation.