Checking the Reticle

Discussion in 'Long Range Scopes and Other Optics' started by Buffalobob, Jun 14, 2010.

  1. Buffalobob

    Buffalobob Writers Guild

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    If you are going to use your reticle for holdover shooting you should check to make sure that the reticle subtends (measures) the correct dimensions that the manufacturer says it measures.

    Here is a target I made up for a Burris Ballistic Plex to determine whether the literature values were correct. I took some painters tape and made a vertical line and then measured down the vertical line with a ruler and placed a strip of tape horizontally so the bottom was at the correct distance from the top of the tape. Once I had the supposedly correct reticle dimensions laid out I took it to the range and carefully measured with a range finder to make sure that the range was actually 100 yards. It seemed to be about 99.5 yards and that was close enough for a holdover scope. I then placed the gun in sandbags and carefully checked to ensure that the reticle marks lined up where they were supposed to be. Sure enough the top of the duplex in the reticle was not where Burris said it was and that was introducing a 2.5 MOA error into everything.


    Just for the curios all of the bullet holes on the left are from a 40X in 308 and I am testing of a F-class load that works with Winchester brass to see if it works with RWS brass. There are 0.5 grain increments of Varget between groups. As you can see the bottom 5 shot group is pretty decent. The fist shot groups is only 4 shots because naturally I forgot to dial out the 36 MOA from the last time I was shooting the rifle and the first shot went up into the wild blue yonder.

    The groups on the left are just me checking the zero on the XP 100 with the Burris ballistic plex and obviously it was not too well zeroed.

    [​IMG]
     
  2. old_heli_logger

    old_heli_logger Well-Known Member

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    Great idea! Thanks for sharing your wisdom with us!
     

  3. sscoyote

    sscoyote Well-Known Member

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    Interesting Bob. That's exactly the same problem i had with my Burris. The plex portion to x-hair was incorrect. Good info. sir.
     
  4. ilscungilli

    ilscungilli Well-Known Member

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    How well did the other hash marks like up with what Burris stated?

    I like my ballistic mildot scope from Burris, but I've been less than impressed with their tech guys. For this reticle, it is calibrated ("around 14X"). I wrote and asked what the subtends would be at 20X, and they said "we don't know, you would have to figure that out." I thought that response was weak.
     
  5. Buffalobob

    Buffalobob Writers Guild

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    The remainder of the reticle from the cross hairs down was perfect. The scope under discussion is the pistol scope. Its elevation dial is in 1/8 inch clicks and there are not markings on it to be useful in dialing up. Thus you are better off using the scope in a holdover manner than trying to dial up for shots.