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5/4/2004 10:22:16 AM EDT
I've owned 3 Colt bolts and I have noticed that all of them have little dents behind each bolt lug.  What are these marks?  Also, I noticed that my third bolt only has these marks behind half of the lugs.  What does that mean?
5/4/2004 2:11:41 PM EDT
[#1]
Probably from where the bolt lug runs into battery with the barrel extension.  
5/4/2004 2:55:55 PM EDT
[#2]
It looks more like sme kind of intentional mark.  I know I've seen milsurp weapons where metal components are struck to test hardness.  Could it be that's what these marks are?  Does Colt do that?
5/4/2004 3:44:45 PM EDT
[#3]
They are stress relief cuts, they are supposed to be there. Only actual Mil-Spec (Colt) bolts have them.

Just another step that almost every other manufacturer skips in the machining process.
5/4/2004 5:05:56 PM EDT
[#4]

Quoted:
They are stress relief cuts, they are supposed to be there. Only actual Mil-Spec (Colt) bolts have them.

Just another step that almost every other manufacturer skips in the machining process.



Thanks for the info.  Why would they only stress relieve 4 of the 7 lugs, though?
5/10/2004 3:34:21 AM EDT
[#5]
I'm looking at one of my Colt bolts and it has the straight line relief mark behind every lug.  Yet another seems to only have four.  Both of these are marked MPC.  I have a later M4 Colt bolt (MPCK) that doesn't have ANY of the relief marks.  I also have bolts (can't remember if they are Colt or not, but chances are Colt) that have a half moon type relief cut instead of a line mark.  Interesting.
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