Pieces Parts ID

[bacarnal]

Just thought I'd throw these out and see if anyone can give an ID. They did come off a projectile.:neutral: Cheers, Bruce.

 

[bacarnal]

Bump. Any guesses? Cheers, Bruce.

 

[spotter]

Hi Bacarnal,,is it copper,,i found something similar looking a long while back that was the gas check from a 4 inch RML,looked almost like an old paint tin lid
sorry but best pic i can find of one from the same type of projectile i found one on http://en.wikipedia.org/wiki/File:4_inch_mortar_bomb_WWI_IWM_MUN_003227.jpg

 

[bacarnal]

Spotter, Close. It is indeed copper and the scrunched up piece inside of it is a malformed lead disk. The two form what is the base closure disk and lead seal for the 155mm Mk 1, Mk 1A1, etc. howitzer rounds. Most US HE (75mm and up, I think) rounds, even to this day that do not have either a base fuze (though they tended to be sealed with lead, also) or a tracer have a base closure disk either made of copper, brass or steel and kept in place with either lead calking, brazing stamping or welding. The reason for the disk originally was because our rounds are forged and stamped much like a cartridge case or a soda can is. When doing this, sometimes minute cracks appear in the base and when the gun fires, could have catastrophic consequences. Hence the base closure disk, which acts as a gas seal. The one pictured is a curiosity to me since it shows that the lead seal under the disk has scooted to the side, and in the other attached picture is another round found during clearance operations with the same problem. It makes me wonder about the accuracy of our 155mm (or bigger) ammunition. If the lead seal was thrown to the side, I would think it would impart a yaw in the projectile thus affecting the accuracy. From range clearance operations in which M107 155mm round were found with the welded steel base plate and no lead seal, it makes me wonder if they discovered the problem, if there was one, or if they just stopped using the lead seal to conserve on strategic materials, found it worked just as good, and didn't go back.
Another thought came to mind about the off set lead seal. Would it have off set due to the sudden acceleration of the round in the bore or would it have been because of the abrupt deceleration when it impacted the ground? Cheers, Bruce.

 

[bacarnal]

Spotter, Close. It is indeed copper and the scrunched up piece inside of it is a malformed lead disk. The two form what is the base closure disk and lead seal for the 155mm Mk 1, Mk 1A1, etc. howitzer rounds. Most US HE (75mm and up, I think) rounds, even to this day that do not have either a base fuze (though they tended to be sealed with lead, also) or a tracer have a base closure disk either made of copper, brass or steel and kept in place with either lead calking, brazing stamping or welding. The reason for the disk originally was because our rounds are forged and stamped much like a cartridge case or a soda can is. When doing this, sometimes minute cracks appear in the base and when the gun fires, could have catastrophic consequences. Hence the base closure disk, which acts as a gas seal. The one pictured is a curiosity to me since it shows that the lead seal under the disk has scooted to the side, and in the other attached picture is another round found during clearance operations with the same problem (you can make out the bulge to the left on the closure disk). It makes me wonder about the accuracy of our 155mm (or bigger) ammunition. If the lead seal was thrown to the side, I would think it would impart a yaw in the projectile thus affecting the accuracy. From range clearance operations in which M107 155mm round were found with the welded steel base plate and no lead seal, it makes me wonder if they discovered the problem, if there was one, or if they just stopped using the lead seal to conserve on strategic materials, found it worked just as good, and didn't go back.

Another thought came to mind about the off set lead seal. Would it have off set due to the sudden acceleration of the round in the bore or would it have been because of the abrupt deceleration when it impacted the ground? Cheers, Bruce.