• How to MOD your MK V Trigger.

    Here are the instructions about how to replace the trigger spring on a Weatherby MK V.
    The MOD will cover all 9 lug Weatherby Rifles from 257 Weatherby Magnum and up to the 460 Weatherby Magnum.
    Please be aware that this info is NOT for the 6 lug version of the Weatherby MK V.
    This instructions can be used to replace or to mod the original spring.
    To cut the spring is something that is out of the hands of both Weatherby.dk and Weatherby.
    So if you do so, it is on your own risk!

    First, the tools needed for the job. Trigger assembly, new spring and a mandrel.
    A hammer and some thin oil will also be handy.
    A Weatherby deskmat under the parts is a matter of course!



    Tap out pin #1:



    Pin gone, now remove "sear" part, by tapping out pin #2:



    Here is pin and the sear removed.
    Now remove the spring, and the disk below the spring.



    Tap out pin #3 and pull the trigger backwards, while you are holding your other hand over the bolt stop pin/spring.
    If not, the pin/spring will fly a feet or two...



    Now there is only one part left, the trigger spring.
    Have a look in the front of the trigger housing, you should be able to see the spring.
    Use a small screwdriver and get it UP through the hole.
    DO NOT try to remove the slottet unbrako to pull it down. It won't work!



    To the left is the old spring, to the right is the new one.


    The original spring is often grinded in the ends to make a flat surface.
    There is no need to grind the new spring, and for safety reasons don't!


    So, it is time to put the trigger back into order. Replace the spring, insert boltstop with spring.
    Insert trigger from the rear, check that the trigger spring is in place and not bended by the trigger.
    Make sure the front of the trigger is OVER the spring.
    If the spring gets bended, adjust it with a small screwdriver. Loosening the slotted hex in the bottom will also help a bit.
    Now, slide the trigger further forward, so the boltstop is resting in the trigger fork.



    Insert pin #3.
    Then insert the spring with the disk in the bottom.
    A small amount of grease/oil on the disk, will make it stick to the spring.
    So it will be easy to get into place.
    Now, press the sear down on the spring, align the holes and insert pin #2.
    This is the most difficult part of the job.
    Here it is done:


    Press down the sear and insert pin #1.



    DONE!!!
    That's all folks, hope this was easy to understand.
    Best of luck while gunsmithing your Weatherby!!!
    Comments 38 Comments
    1. fasttrx88's Avatar
      fasttrx88 -
      thanks alot for the demo it helped a lot and worked great
    1. 340 Weatherby's Avatar
      340 Weatherby -
      Glad I could help!
    1. tommyh's Avatar
      tommyh -
      Where did you get the green thing?
    1. dubyam's Avatar
      dubyam -
      That's a "bench block."

      http://www.sinclairintl.com/gun-part...prod34052.aspx

      http://www.midwayusa.com/product/265...ng-bench-block

      There are likely other sources, but that'll at least get you started.
    1. 340 Weatherby's Avatar
      340 Weatherby -
      Mine is from Sinclair. Just made the mistake not buying the handgun one.
      Has the same holes + a channel for the slide.
    1. JaimeChinook's Avatar
      JaimeChinook -
      This thread has legs!!

      Thanks for posting this. I almost feel ready to tackle this job :-) Just one question: I can't see the step where you take out pin #3. I assume it's at the step where you say, "Pull the trigger backwards, while you are holding your other hand over the bolt stop pin/spring." Correct?

      Just an FYI. I'm working on a one-year old Accumark in 300 Win Mag. The gun currently has about 3.3# trigger pull. I can completely remove the allen screw intended to adjust this pull and it stays unchanged. As it came from the factory, the screw was about 3 full turns "out" and more or less "loose". I screwed it in to the point of contact plus 1/2 turn and the trigger pull is still unchanged.

      OK, here's another question, "could the firing of about 200 rounds have loosened this trigger-adjust screw?"

      Any other thoughts?

      Finally, an OT: Do you recommend brass or steel pin punches for this?

      Thanks again!!
    1. 340 Weatherby's Avatar
      340 Weatherby -
      You are correct, after removing pin#3 you can pull the trigger backwards.
      The issue with the triggerpull is something I have seen on several triggers.
      The pull can never be adjusted below 3.5-4.0 pounds wathever you do.
      Only way of fixing it is to replace the spring.
      The adjust screws has a seal on them from the factory.
      At least the triggers I have seen.
      I used a steel punch and it worked perfect,
      In teory, a brass punch is even better.

      Update: Fixed missed info for pin #3 in the tutor.
    1. JaimeChinook's Avatar
      JaimeChinook -
      Great. Thanks so much.

      My adjust screw was so loose from the factory I couldn't tell if my allen driver was turning it or if the driver was too small and was turning in the screw. QC issue? This gun also came without one of the sling studs (Weatherby promptly sent me one) and the barrel was unbelievably coated with copper indicating many more than just one or two test rounds having been fired.

      I can't say the trigger has a lot of creep but when squeezing, I can always feel a slight give/stop just before let-off. I wonder if I can hone that off when I have the trigger apart...??

      On the good side, I've finally found a load using Berger 185 VLD hunting that gives me just under 1 moa.
    1. Dr. Vette's Avatar
      Dr. Vette -
      I use a Dremel with a buffing wheel and some Flitz to smooth out the sear and the trigger. It doesn't take much but it sure helps the feel of the trigger. Just polish the surfaces that slide against each other.
    1. JaimeChinook's Avatar
      JaimeChinook -
      I wonder if 340 Weatherby would be so kind as to add 2 arrows to the pictures in this thread showing exactly which surfaces on the sear and trigger to polish; I think pictures 3 and 5...
    1. 340 Weatherby's Avatar
      340 Weatherby -
      First, I would like to state that playing with the trigger parts is something that are out of my hands.
      And as well Weatherby's control. So, please be careful, and remember that the full responibility is yours only.


      What we need to do is just polishing the surfaces NOT alter any angle etc.
      If we look at pic #3 you can see what parts are involved, and what surfaces that are in contact.
      Dismantle the trigger as shown at pic #3 and now try to understand how the parts works together.


      Trigger surface to polish shown from above. Marked with a sircle.






      The new arrow shows the surface on the trigger that need polish.






      Arrow shows the area to polish.
      It's critical to not alter any angle or shorten any surface here.
      Polish only!

    1. JaimeChinook's Avatar
      JaimeChinook -
      All I have to do is wait for my spring to arrive :-)

      Can you please give advice on securing my adjust screw after I do this work? I hate the thought of it being so loose. Loc-Tight? What color or spec?

      Thanks
    1. sleath66's Avatar
      sleath66 -
      I have two older weatherby deluxes from back in the 1970s. I ordered springs for them but they are a little larger in diameter and dont seem to fit. Are the springs in them normally smaller?

      Quote Originally Posted by 340 Weatherby View Post
      First, I would like to state that playing with the trigger parts is something that are out of my hands.
      And as well Weatherby's control. So, please be careful, and remember that the full responibility is yours only.


      What we need to do is just polishing the surfaces NOT alter any angle etc.
      If we look at pic #3 you can see what parts are involved, and what surfaces that are in contact.
      Dismantle the trigger as shown at pic #3 and now try to understand how the parts works together.


      Trigger surface to polish shown from above. Marked with a sircle.






      The new arrow shows the surface on the trigger that need polish.






      Arrow shows the area to polish.
      It's critical to not alter any angle or shorten any surface here.
      Polish only!

    1. JaimeChinook's Avatar
      JaimeChinook -
      I have two older weatherby deluxes from back in the 1970s. I ordered springs for them but they are a little larger in diameter and dont seem to fit. Are the springs in them normally smaller?
      When I ordered my spring, I noticed the description said it was for "current US manufacture"...
    1. 340 Weatherby's Avatar
      340 Weatherby -
      I have used the new springs in several japanese MK V's without any problems.

      Sent from my Galaxy S III Using TapaTalk
    1. JaimeChinook's Avatar
      JaimeChinook -
      Can you please give advice on securing my adjust screw after I do this work? I hate the thought of it being so loose. Loc-Tight? What color or spec?
      340 Weatherby... You've created such a helpful thread here I hate to bug you further... But can you comment on my loose adjust screw question?

      Many thanks :-)
    1. 340 Weatherby's Avatar
      340 Weatherby -
      You can use a weak Loctite on the screws.
      First remove screws and degrease the screws and threads.
      Use a weak or medium Loctite like #221 or #241.
      You can also buy Gun-Tite from Uncle Mikes. (I believe it's #241 in the bottle)
      Link: http://www.midwayusa.com/product/241...ocker-6ml-tube
      Have a drop on the screws before adjusting the trigger.
    1. Buano's Avatar
      Buano -
      Thanks for the very useful post!

      Where do I order a spring from? Are there different springs to choose from?
    1. dubyam's Avatar
      dubyam -
      Easiest thing to do is order from Ernie the Gunsmith:

      http://erniethegunsmith.com/catalog/c14_p1.html

      I believe the spring also works with the Japanese trigger, though it will not work with the German trigger.
    1. Dr. Vette's Avatar
      Dr. Vette -
      Yep, as I told him on another board I've used it in a Japanese trigger with no problems.