Ruger M77 mkII scope mounting issues

Discussion in 'Rifles, Bullets, Barrels & Ballistics' started by Welderboy250, May 26, 2013.

  1. Welderboy250

    Welderboy250 Well-Known Member

    Messages:
    46
    Joined:
    Apr 19, 2013
    I'm new here and I know this is not the optics forum but I believe the problem lies with the receiver so ill post here, please move if it is the wrong place to post.
    I found this ruger heavy brl .204 on gunbroker for a friend. It had a horrible scope mounted. Didn't know at the time someone had done what seems to be a real hack job mounting. There was what appears to be a rectangular section of a plastic water bottle in the front ring under the scope tube. I observed this was necessary for the bell to clear the barrel without taller rings. Removed the plastic and laid the new scope in and did a quick rock test to see how bad things might be for alignment. IT WAS HORRIBLE! Pressing down over the front ring lifted the scope off the rear slightly, pressure over the rear one lifted it off the front one a good eighth inch! Some careful study eventually yielded the conclusion that the integral ring mounts are not machined parallel. There is no detectable problem with the rings, it is all in the receiver. What should be done with this thing?
     
  2. FEENIX

    FEENIX Well-Known Member

    Messages:
    10,984
    Joined:
    Dec 20, 2008
  3. Hairtrigger

    Hairtrigger Well-Known Member

    Messages:
    356
    Joined:
    Jan 10, 2009
    Always a good idea to lap the rings before placing a scope in them.
    I have seen some very good alignment on River rifles but did see one that was terrible also
     
  4. benchracer

    benchracer Well-Known Member

    Messages:
    1,505
    Joined:
    Dec 18, 2009
    Another, admittedly more expensive option, is to go with a Picatinny rail from Murphy Precision. You will have to have a gunsmith drill and tap the receiver for the rail, but you will have a bomb proof setup when you are done. Another advantage is the ability to install a canted rail to give you a bit more elevation adjustment.

    I realize it is just a .204 and probably doesn't need a super strong mounting system or the extra elevation from a canted base, but the options are there to be had if you want them.
     
  5. FEENIX

    FEENIX Well-Known Member

    Messages:
    10,984
    Joined:
    Dec 20, 2008
    I looked into that alternative before too, yes it is indeed very expensive and don't forget that the receiver needs to be drilled and tapped too as it does not use the dovetail.
     
  6. FEENIX

    FEENIX Well-Known Member

    Messages:
    10,984
    Joined:
    Dec 20, 2008
    No lapping required if you use Burris signature rings with inserts.

     
    Last edited by a moderator: Sep 8, 2018
  7. Welderboy250

    Welderboy250 Well-Known Member

    Messages:
    46
    Joined:
    Apr 19, 2013
    I think if I just started lapping I would not have suitable contact area before the top half bottomed without the scope being calmed at all. I mean the rear ring is seriously canted rearward, either that or the front one is canted forward or a combination. Wich brings me to my next concern. The back ring looks to need to have more material removed to make it right and I'm concerned that the elevation adjustment is going to b whacked by the time I get it zeroed having removed so much material from the one ring. I also question wether or not those fancy Burris rings would allow enough offset without the scope tube getting into the metal at the edge of the ring. But even that concern would be irrelevant unless I can convince him to spend that much on the thing. He would prob just cut his losses and sell it before that point. I guess what I'm really asking is for advice on how to make the best of what I have to works with without making it a bigger mess than it already is. How would u suggest I go about attempting to keep the scope tube parallel to the bore throughout all this material removal? Or should I just throw in the towel right now? I think it's possible the thing might be a shooter as it appears the lugs have been laped and the receiver face squared up.
     
  8. Hairtrigger

    Hairtrigger Well-Known Member

    Messages:
    356
    Joined:
    Jan 10, 2009
    My experience with Ruger has been positive when I have had issues.
    Call them and they will make it right
     
  9. Welderboy250

    Welderboy250 Well-Known Member

    Messages:
    46
    Joined:
    Apr 19, 2013
    I would but like I said its a used gun.....
     
  10. FEENIX

    FEENIX Well-Known Member

    Messages:
    10,984
    Joined:
    Dec 20, 2008
    How much is your friend willing to spend to make it work?
     
  11. AZShooter

    AZShooter Well-Known Member

    Messages:
    2,233
    Joined:
    Dec 12, 2005
    Any chance of posting a picture?

    The first thing that came to mind is that the front and rear rings are switched. Or the two rings have the same height and are not the correct rings for this rifle. The receiver is higher in the front so a shorter ring goes there.

    Are the rings fitting properly into the integral receiver bases? It is possible that the rings were installed without actually fully dropping into the machined recesses.
     
  12. FEENIX

    FEENIX Well-Known Member

    Messages:
    10,984
    Joined:
    Dec 20, 2008
    I was thinking the same thing. Here's a 1" off my .338 WM.

    [​IMG]

    The reason I asked what the OP's friend is willing to spend is because depending on height/size/finish, they can be had for $30-$40 new and used for $15-$20 (or less if one look hard enough) just in case previous owner managed to screw up the ring(s).
     
  13. MudRunner2005

    MudRunner2005 Well-Known Member

    Messages:
    12,393
    Joined:
    Oct 13, 2008
    EGW (Evolution Gun Works) also sells an M77 picatinny base, but, like the Murphy, you will have to have the reciever drilled & tapped.

    Ruger M-77 Picatinny Rail Mount: Evolution Gun Works Inc..

    I use EGW bases exclusively on my Rem 700 rifles, along with TPS TSR rings. I have found that to be a damn-near indestructible combo.

    Now it has me really thinking about putting them on my old Ruger 77's. It would be worth the money to be able to run an infinite ring and scope combination, plus it would truly the make the rifle alot more versatile.
     
  14. Welderboy250

    Welderboy250 Well-Known Member

    Messages:
    46
    Joined:
    Apr 19, 2013
    Thanks for the replies and and working with me on this. I don't have a hard number on what he be willing to spend only that the more it is the harder it will be to talk him into. But enough of that.
    The rings are the correct set with the tall one in the back and they are seating properly into the base. I have eliminated the issue being with the rings themselves or with a seating issue as I have laid two straight edges on top of the receiver, one on the front base portion and one on the rear. At this point they should be parallel but they are not. The font straight edge appears rathe parallel to the bore but the rear straight edge looks to be sloping up as u go forward (high in the front).
    Part of what I'm getting at here with all my questions is how do I get the scope to be fairly parallel to the bore when I'm done and not wind up with it looking up at the sky like I suspect it would if I just start cutting on the rings without considering the consequences.
    Thanks for all your help. Please let me know if u have any suggestions on keeping aligned with the bore.