question about a part of two of my scopes

[JR Hartman]

whats that little thing stuck at 45deg into the left bottom of my scopes? Its just under the turrets, and shaped like a little tube stuck into the scope.

half an inch long, maybe 3/8ths in diameter.

one is in a Bushnell AR 223, 1-4x20 and the other is on my Scorpion Copperhead 4-12x40 AO

 

[Trinimon]

That's the port where they fill the scope with gas (nitrogen or argon?) to prevent it from fogging.

 

[tiriaq]

Could be where a spring loaded plunger is installed, in lieu of a flat spring inside the tube, to spring load the tube which carries the reticle, and which is shifted to provide for adjustment.

 

[JR Hartman]

ok, cool, thanx. Its not on my Simmonds 3x9x32 AO. Someone told me it was for the illumination, but I don't think either of these are illuminated.

 

[Trinimon]

Is it this what you're referring to?

 

[JR Hartman]

yep

 

[Trinimon]

That's the gas purge/fill port.

 

[JR Hartman]

ok, cool, thanx. how did they fill/purge it on scopes that don't have that?