by Frank Kleinburg (firstname.lastname@example.org)
(Original article posted at www.recguns.com)
Let me discuss how the trigger on the Model 70 works. Knowing how it works
will allow you to know how a gunsmith would
The trigger mechanism on the Winchester Model 70 is remarkably simple. Remove
the barreled acton of a Model 70 from
it's stock and you can see just how simple it is. You will see a trigger that pivots on a pin. Look at the rear portion of the trigger
(normally hidden by the stock) and you will see a square head screw (the trigger stop screw), three nuts, and a spring (we'll call it
the trigger return spring).
The purpose of the trigger stop screw is to limit the amount of over travel
of the trigger. It is possible to screw the trigger stop
screw in far enough that you will not be able to pull the trigger enough to release the sear. Ideally the trigger stop screw should
be screwed in as far as it can and still have enough trigger movement to reliably release the sear. This will allow for the greatest
amount of adjustment of the trigger spring tension.
Tension on the trigger return spring determines a majority of the trigger
pull weight (the rest of the trigger pull weight comes
from the friction between the trigger and the sear). The spring surrounds the trigger stop screw, both can be seen just behind
the trigger. The trigger stop screw is held in place by a pair of captive nuts, one on each side of the part of the trigger the stop
screw passes through. A third nut sets the tension on the trigger spring. Tightening this third nut (turning it clockwise) against the
trigger spring will increase the trigger pull. And turning it counter clockwise will decrease the trigger pull weight.
After making any adjustments, be absolutely sure to test for an excessively
light trigger. To do this, screw the barreled action
back in the stock. With the bolt cocked, in the closed position on an empty chamber, and the safety off, butt down the rifle. That
is hold the rifle barrel pointing upward, let the butt bounce on the ground. It should take a considerable bump to cause the firing pin
to drop (on the empty chamber).
On a friend's pre-64 Model 70 trigger, the spring had to be changed because
enough of the trigger spring pretension could not
be removed to get an acceptable trigger pull weight. Yet on another (on one of those new classic actions), it was possible to
remove ALL of the trigger spring pretension. This is a dangerous situation because only the trigger to sear tension keeps the
cocked rifle from firing.
Well I hope you now have a better understanding of how a Model 70 trigger
works. Of course for all trigger pull weight
adjustments you should take your rifle to a reputable gunsmith.