help with optic please

Discussion in 'AR-15 Discussion' started by hawkguy, Jun 19, 2012.

  1. hawkguy

    hawkguy Well-Known Member

    4,979
    59
    48
    a quick question. please understand i am very new to AR's, so please forgive if this is a DUH type of question....

    i have a millet red dot. a 1" tube red dot. here is a link.

    http://www.opticsplanet.net/millet-electronic-red-dot-sights.html

    bought it as a cheap red dot for my mini 14, i haven't used it much, but it seems to be a decent red dot imo.

    my question is....how can i use this on my S&W M&P sport? it is too low to clear my front post on regular rings.

    i will need some type of elevated mount for a picatinny rail. it needs to be with 1" scope rings. could i co-witness with my irons with this optic? i would like to go pretty inexpensive if possible. one day i hope to have an eotech on my AR, but that might be in the distant future....$$$$:eek:

    it would be really nice to use an optic i already have for awhile.

    thanks for any help.
     

  2. hawkguy

    hawkguy Well-Known Member

    4,979
    59
    48
    thank you. i was actually just about to post a link to this on midway when i saw you posted this. it says it is a "weaver mount"....will it work on a picatinny rail?

    the price is right! :D

    but my question would be....how do i know if this will clear/co-witness with my standard front sight? this is something i simply don't understand about ARs....:confused:
     
    Last edited: Jun 19, 2012
  3. EW1066

    EW1066 Member Supporter

    344
    0
    16
    Based solely on the product pictures, it appears as though you will get either a lower 1/3rd co-witness or maybe even an absolute co-witness. It's a little difficult to tell from just the pictures.

    From the NCSTAR web site:

    "Introducing the most Versatile Mount to the NcSTAR Line-up. This Single Accessory will allow you to mount virtually any rifle scope of red dot sight to your rifle in a number of different configurations. The Famous NcSTAR QR Lever System makes mounting the MARCQ to your flat top Lightning Fast. The Rings are 30mm with 1 inch inserts, and the Rear Ring rides on a dovetail so you can adjust the spacing for customized fit. The Rear Ring is also removable so you can set up your Red Dot Sight to Co-witness with your Iron Sights. Made of Hard Anodized Aluminum and Solid Steel, once you’re locked in this mount isn’t going anywhere!"

    EDUB
     
  4. hawkguy

    hawkguy Well-Known Member

    4,979
    59
    48
    thanks again for your help.

    i have seen this 1/3 vs absolute c0-witness mentioned before, but i don't understand it at all. could you please explain the difference?
     
  5. EW1066

    EW1066 Member Supporter

    344
    0
    16
  6. EW1066

    EW1066 Member Supporter

    344
    0
    16
    Or watch this video:

    [ame]http://www.youtube.com/watch?v=qj3NY2jwDEo[/ame]

    EDUB
     
  7. hawkguy

    hawkguy Well-Known Member

    4,979
    59
    48
    thanks, gentlemen!

    now, how do you know which type of co-witness you will get with a specific optic/mount? is it an adjustment to the scope or more related to your set up/hardware? in what ways can you acheive the co-witness you prefer?

    sorry for so many ?'s.
     
  8. Quentin

    Quentin New Member

    7,551
    1
    0
    Normally you chose a mount/riser that gives you the right height for cowitness. A taller mount is required for bottom 1/3 than absolute. Look at Purehavoc's diagram and decide which you want. I like bottom 1/3 myself but many like absolute.
     
  9. hawkguy

    hawkguy Well-Known Member

    4,979
    59
    48
    thanks, but this is still where i'm at a loss.....how do you know what mount/riser is right for which type of co-witness?
     
  10. CHLChris

    CHLChris New Member

    2,523
    0
    0
    Some of it is good old-fashioned research and math. The nicer scopes (not NcStar or Millet) will have on their website every possible measurement for you to see. If you measure your iron sights (or use website measurements if using BUIS like Magpul, etc.) you can know what #'s to look for.

    Also, some Red dots have mounts specifically designed to provide cowitness through standard AR-15 iron sights. I am thinking the Burris Fastfire with its AR-F3 mount. I'm sure there are others in this category.
     
  11. EW1066

    EW1066 Member Supporter

    344
    0
    16
    I have a lower 1/3 co-witness and the center of my optic is 1.75 inches above the top of the receiver.
     
  12. Quentin

    Quentin New Member

    7,551
    1
    0
    You might check with Millet and also read through user reviews of that model at Cabelas, Brownells, Midway, etc., someone may say. You could get a steady handed friend hold it to the correct height and measure. Tall mounts are probably very close but that's just a guess.
     
  13. okdonk

    okdonk New Member

    2,821
    0
    0
    My setup which is Eotech XPS2-0 with Magpul front+rear. It has obsolute cowitness.
     
  14. Quentin

    Quentin New Member

    7,551
    1
    0
    hawkguy, Looks like you found a steady handed friend. :D

    You may need very tall risers for 1.75 in. I'm not near my ARs but guess my mount is about that tall.
     
  15. EW1066

    EW1066 Member Supporter

    344
    0
    16
    The biggest problem you will have is trying to find accurate dimensions before you buy. From what others have said on other forums the center of the optic needs to be 1.5 inches above the receiver for absolute co-witness. 1.75 for lower 1/3. With a 1 inch OD tube the inside of the bottom ring should be 1 1/4 inches above the top of the receiver for lower 1/3. if it 1 inch ID subtract the the wall thickness of the tube from the bottom of the ring. but again getting ACCURATE dimensions from web sights won't be easy.
     
  16. hawkguy

    hawkguy Well-Known Member

    4,979
    59
    48
    thanks EW1066

    took a chance on the ncstar mount you suggested (it was only $30, so...)

    this mount, with my existing red dot, seem to co-witness well. just from looking through, it seems to be an absolute co-witness, as when i have a proper cheek weld, my dot does seem to sit right on top of my front post.

    i know only time will tell, but so far it seems like a solid mount that will work out great. i'm pretty excited cause i actually bought this millet red dot for $25 used (normally $80+), putting my total investment at about $50-60. i used this millet red dot on my mini and for the $, it seems to be a very good optic.

    i realize this is a pretty "cheap" set up, but it will be nice to fool around with a red dot on my new AR, until i can save up for something better.

    here's a pic
     

    Attached Files:

    Last edited: Jun 23, 2012
  17. EW1066

    EW1066 Member Supporter

    344
    0
    16
    You are welcome. I like to help in any way I can.

    Don't forget a range report. Would like to hear how it works out in actual use.

    EDUB
     
  18. locutus

    locutus Well-Known Member Supporter

    16,606
    770
    113
    I prefer absolute co-witness. Can't really explain why, it just feels "right" to me.

    But a person really should try several options, and use the one that "feels right."