Rifle Scopes Question about a "part" on a Falcon Menace

Heat

Sergeant
Full Member
Minuteman
Aug 12, 2008
271
0
Southern Ohio
My dad recently bought a rifle package here on the Hide. It has a Falcon Menace 5.5-25 FFP on it and I'm not sure what the "stud/screw" on the left side of the body, sticking out at a 45 deg angle is? Is that a zero stop? It may be a dumb question but I can't find any info on it. Thanks for the help.

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