View Full Version : Any idea what the little knob on the underside of this scope is for?

May 26, 2006, 22:03
I picked up thid scope, its a Millett 4~16X56 / 30mm tube (http://www.millettsights.com/online/pages/p3.php)
On the underside there is a smallish button on the underside, it's not really a knob altho you can turn it with strong finger pressure. It was a couple slots where a spanner of some sorts could be used. I tried turning it, but didn't notice anything happening.
No manual and so far Millett's catalog and website are useless.
Any ideas?

May 26, 2006, 22:19
if you really want to know, e-mail them and ask.......wild guess on my parts, a purge connection, or a point for nitogen fill.

May 30, 2006, 16:53
I can't tell from the pic, but there was a scope that allowed you to lock the internal ajustments in place using a key. It sound like thats what you're talking about.
It was supposed to remove "slop" when making ajustmets to range & windage by pushing the internal tube against the ajustment shafts.

June 02, 2006, 21:57
I am almost postive that its to lock the internal adjustments....


June 06, 2006, 15:42
I think some Burris scopes are available with a "Posi-Lock" screw that looks similar to the picture.... It is used to "lock" the reticle adjustments.

June 06, 2006, 16:42
Well I just had a very pleasent conversation with a technical services rep. from Millett. He explaned in simple terms that the "little knob" provided spring tension for the adjustments and that it should not be loosened or removed, that would release the nitrogen gas charge inside.
I explaned that this scope was used, he said "...put the scope inside the refrigerator overnite, then take it out into a warm room: if it fogs, you've lost the charge, give us a call.....and we'll replace it." :cool:
Then I asked if it was suitable for use on a .300RUM and he said "...it would hold up under the heaviest magnums..." Again, if it fails, just call for a replacement. Can't get any better than that.
Tonite the Sendero sleeps in the garage (it's in the low 50's overnite) and see what it does during the day....Hunting seasion is ususlly colder than a well diggers arse around here, can't be scope'n big bucks thru a fogged lense. :wink: