Welcome to MGO's Internet Discussion Forums…Please Consider Becoming a Dues-Paying Member of the ORG…Click >>>>>HERE<<<<< for more info…………****DONATIONS**** can also be made toward MGO's Legal Defense Fund and/or MGO's Forums >>>>>HERE<<<<<

KROGER

Results 1 to 10 of 10
  1. #1
    I am a Forum User
    Join Date
    Oct 2009
    Location
    Rochester Hills,Mi.
    Posts
    4,124

    how to clean a scope OBJECTIVE LENS

    I recently mounted a Bushnell AR scope to my gas piston Adams Arms AR-15.
    After sighting it in, later went to clean rifle & noticed the objective lens was very fogged up.
    Believing the scope to has sprung a leak, causing the lens to fog, I started looking into returning the scope for repair.

    As I removed the scope from the mount, I noticed some residue on the bottom of the housing that holds the objective lens.
    Using a washcloth & warm water, I wiped this residue off..then realized what I believed to be lens fogging was actually powder residue
    that had collected on the lens. Seems gas is vented thru the holes on top of the handguard, below the scope & residue collects on the scope lens.

    Knowing that lenses have special coatings & wanting to NOT mess up the objective lens, what would be the best way to clean the lens ?

    also would like to know ideas on how to prevent this from happening again, if mounted to this AR ?

    Anyone else had this problem ? If so, how'd you address it ?

    Thanks in advance for helpful replies.

  2. #2
    I am a Forum User
    Join Date
    Dec 2010
    Location
    West of Bravo
    Posts
    7,473
    The really effective heptane-based cleaning solutions and canned blow off gas are no longer available due to EPA rules, so lens cleaning has become much more involved.

    The Zeiss lens cleaning kit is probably the best system presently available.

    Start by blowing off any loose particles to avoid scratching the lens when cleaning it. Use the little bulb in the Zeiss kit. Do not use compressed air from a compressor because it will be contaminated with scuzzy water and oil. Concentrate on the perimeter of the lens to get as much crud out of the ocular bell housing inside walls as possible.

    Moisten (not soak) the microfiber cloth with the Zeiss cleaning solution. Then very gently wipe off the lens surface with a spiral motion, starting in the lens center and working to the perimeter.

    Inspect the cloth carefully (every time) after you get to the outside edges of the lens. It will often pick up abrasive particles trapped by threads and rubber seals inside the ocular bell. These will scratch your lens if they are not brushed/blown/vacuumed off the cloth.

    Allow the lens cleaning solution to evaporate and inspect the lens surface.

    Don't be dismayed if there are still some streaks after the solution evaporates. Just repeat the procedure until there are no more streaks.

    A kill flash is pretty effective at preventing scum build up on objective lenses.

  3. #3
    I am a Forum User
    Join Date
    Dec 2010
    Location
    The ugly part of Hell, Michigan
    Posts
    1,480
    I use the disposable lens cleaners available at the optical department at wal mart.

    Handy, convenient, and cheap. They do have a shelf life so it doesn't pay to get the large box

  4. #4
    MGO Member Ol` Joe's Avatar
    Join Date
    Jul 2005
    Location
    the dog house
    Posts
    10,661


    I use a lens brush and Leupold lens pen for most of mine unless very dirty.
    "Saepe errans, numquam dubitans --Frequently in error, never in doubt".

    The trouble with the Internet is that it's replacing masturbation as a leisure activity. ~Patrick Murray

  5. #5
    I am a Forum User
    Join Date
    Oct 2009
    Location
    Rochester Hills,Mi.
    Posts
    4,124
    Well, I googled "cleaning a scope lens" & read a bunch of links. The residue on my lens was stuck on it..
    wouldn't just blow off. I have stuff to clean camera lenses, from years ago, (forgot I even had them)
    Found a product called Zooke, for lens & face shield cleaning, supposed to be safe for scope lenses.
    Using a clean soft cotton cloth (old t-shirt) I put a drop of Zooke on the cloth & starting in the center,moving in a circular motion,
    worked around the lens, ending on the outside edge. Did this repeatedly, using a clean spot on the rag often, as the reside came off.
    This system removed the residue, & did not appear to damage the lens.

    I'll add that this accumulation on the front lens collected in less than 100 rds of shooting my hand loads.

    So, I've got the lens clean, wondering how to prevent a re-occurrence .
    Maybe sealing off the vent holes on the top of the hand guard, just beneath the front scope lens.
    There by forcing the gasses to exit the holes @ the bottom of the hand guard ?
    I did send a message to Adams Arms, to see what solutions they suggest..

  6. #6
    MGO Member Ol` Joe's Avatar
    Join Date
    Jul 2005
    Location
    the dog house
    Posts
    10,661
    Joe if you are getting powder gases blowing on your lens STOP!
    The coatings are not always as tough as we like to think and easily damaged. Lens can be gas etched over time too. plus when you wipe the crude off you are rubbing carbon grit on the lens furthering the possibility of damage. Gun oils, solvents, etc will damage coatings too, keep covers on your lens while cleaning, don't use your shirt tail or paper towel to wipe, never use Windex, dish soap or other household cleaners on them.
    "Saepe errans, numquam dubitans --Frequently in error, never in doubt".

    The trouble with the Internet is that it's replacing masturbation as a leisure activity. ~Patrick Murray

  7. #7
    MGO Member JDG's Avatar
    Join Date
    Aug 2008
    Location
    Battle Creek
    Posts
    8,231
    My friends wife somehow just unscrewed his scope lenses, cleaned both sides, and ran a rag through his tube, cleaned it up real nice for him.... lol
    Active airport shooter

  8. #8
    I am a Forum User
    Join Date
    Oct 2009
    Location
    Rochester Hills,Mi.
    Posts
    4,124
    Got a reply back from Adams Arms Re: how to prevent this problem..
    only had 2 suggestions..
    1) Move the scope rearward, to avoid gasses.
    2.) Obtain a sunshade for the front of the lens.

    Thought they may have other options.
    Had no Idea that going to a gas piston rifle, rather than the D.I. system, would result in this kind of problem.

  9. #9
    I am a Forum User
    Join Date
    Dec 2010
    Location
    West of Bravo
    Posts
    7,473
    Quote Originally Posted by joepistol View Post
    Got a reply back from Adams Arms Re: how to prevent this problem..
    only had 2 suggestions..
    1) Move the scope rearward, to avoid gasses.
    2.) Obtain a sunshade for the front of the lens.

    Thought they may have other options.
    Had no Idea that going to a gas piston rifle, rather than the D.I. system, would result in this kind of problem.
    Wouldn't the Magpul MOE SL hand guard divert the gasses from your scope if you were to block the M-LOK slots at the two and ten o'clock positions?

    A kill flash will also protect your ocular lens.

  10. #10
    I am a Forum User
    Join Date
    Oct 2009
    Location
    Rochester Hills,Mi.
    Posts
    4,124
    I took my AR to my gunsmith & discussed the problem & potential solutions.
    The factory hand guards have (aprox.) 1/4" dia. holes, along the top surface of the hand guard,
    as well as along the bottom of the surface of the lower hand guard.

    My thought was I could plug the top holes, and allow the gasses to vent out the bottom, so gasses wouldn't pass in front of the objective lens.
    Was going to use cloth duct tape (super sticky) to the inside of the hand guard, decided to use aluminum foil tape, as used for heating ducts,
    as it's metal , & should tolerate the high gas temps it may /will be exposed to, in use.

    My gunsmith agreed that the gasses should vent to atmosphere (with the lower hand guard holes remaining open) without causing any problem.
    Borrowed some foil tape & plugged the upper hand guard holes, reattached hand guards, & then, re-mounted my clean scope.

    Hope to test it at the range, tomorrow. Supposed to be the warmest day of the week (mid-50's) good day to give it a try.
    Will shoot some rounds & see if any residue collects on the objective lens.

    I did look for a scope shade, and a flash kill, to see if I could find one for my Bushnell AR Scope, w/ 42 mm lens
    & couldn't find either part for this specific scope. Unfortunately, the lens casing is not tapped with a universal size thread pitch.

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •  
only search Michigan Gun Owners Forums
MGO's Facebook MGO's Twitter