IBM bolt marked X-Explanation?

[mpd1978]

Anyone know what a "x" stamped on an IBM round "aob" marked bolt means? Also it has a "c" stamped on the side. ?? Bolt wasnt in a carbine when i got it, just bought as a spare.
thanks

Information

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[INLAND44]

Auto Ordnance for IBM. Some of them had heat-treating problems. The 'X' marks the accepted ones. There's something else about the 'X' but it escapes me at the moment.

[BrianQ]

The X had nothing to do with heat treating. It means the bolt does not have all the revisions incorporated into the round bolt design.

[Phrogpilot]

Actually, the "X" means it was used for interchangeability tests...

[INLAND44]

The X had nothing to do with heat treating. It means the bolt does not have all the revisions incorporated into the round bolt design.

If you'll notice, I didn't say the 'X' had anything to do with heat treating. I simply stated that some AOBs had heat-treating problems which is well-known. The 'X'-marked bolts were obviously accepted and used, so that was correct. The thing I forgot was what you mentioned.

[BrianQ]

Auto Ordnance for IBM. Some of them had heat-treating problems. The 'X' marks the accepted ones. There's something else about the 'X' but it escapes me at the moment.

So the ones without the X weren't accepted? Strange because a whole bunch of AOB bolts don't have an X on them.[COLOR="Silver"][COLOR="Silver"][COLOR="Silver"]

---------- Post added at 09:53 PM ---------- Previous post was at 09:51 PM ----------

Actually, the "X" means it was used for interchangeability tests...

No it doesn't. It means they bolt doesn't have all the design revisions incorporated into the round bolt design. If you can find an ordnance document that says bolts marked with an X 1/2" rear of the locking lug were used in interchangeability tests post it. In the mean time you might want to read MAJ Nielsen's Memorandum dtd, 4 September 1944.

[Rustship]

Brian Q, you need a course in Manners

[phil441]

Actually, we all need to settle down.
BQ has a tendency to be brusque and to the point, and a bunch of us have a tendency to be condescending.
The trick here is to gather as much information as possible without becoming upset with each other.
Lets face it guys, the real experts here are a limited resource. Just glean what you can from them (agree or not) and continue on.
The info can continue on long after we're all gone.
Just an opinion,
Phil

[BrianQ]

Sorry Rustship, I didn't know you were so sensitive. I guess it is okay with you to post incorrect info and when done it should not be corrected?