davis dst in beck rifle

[hortonstn]

i'm trying to use a davis dst in a small 40 cal A weight rifle i'm building, the wrist
is very small and the lock doesn't want to set without pulling the rear trigger then cocking the hammer basically i guess i've made the wrist to small. is my only other choice a single plain trigger pinned thru the lock area?
your thoughts are appreciated  ( the lock is a large siler)
paul

[Acer Saccharum]

Now, I don't know how close the triggers are to working...but.... there may be something you can try.

the heavy spring for the rear trigger is held down with a big screw at its tail. Adjusting this screw will determine how hard the rear trigger hits the sear when the triggers are tripped. If you back off that screw, you may find that the lock will set without the triggers set. If you back off too much, the set triggers may not trip the lock. If you find a spot where this works, shim it underneath the spring so you can set the screw firm, and still get the adjustment you need.

A really viable alternative is to bend the sear bar up to gain more room for the DS triggers to operate. You'll have to HEAT the bar, and then re-harden and temper.

Both of these alternatives are far better than ripping the triggers out and starting all over.

[mjm46@bellsouth.net]

It's been my experience with DSTs that little things have great effect on their function. I agree with what Acer said but in addition, you may have the triggers a little too deep, try shimming the trigger plate front and back a little, if this works and the trigger plate extends too proud just file it down. By the lock not full cockng till the trigger is set tells me that the trigger bars are hitting/pressing on the sear bar preventing the sear from engaging in full cock position. If you can full cock the lock with the triggers out, your triggers are causing the problem.

[Curtis]

Paul,

All the previous advice given is definitely worthy of looking into.

Another thing you may try is putting some transfer color on the bottom of your sear (lipstick, in-letting black, or whatever will show well), then try to cock the lock with the triggers un-set.  Then remove the triggers and see if you can find the color transferred to one of the trigger bars.  If it is a clearance issue you should have a mark on the top of a trigger bar, and by shimming the trigger plate a little will allow the lock to cock when the triggers are unset.  I would try shimming it, and if a small shim allows the triggers to function properly, then you can file some off of the top of the trigger bar that is too tall.  Remove the shim and keep fitting and trying until you hit the sweet spot.

I hope that made sense.

Curtis

[kutter]

Is there a back lash adjustment screw on those? If not a simple small set screw under the tip on the main spring can limit it's travel and take the tension off the rear trigger when it's relaxed.
That'll allow the rear trigger to sit back down on it's own and the sear to move freely when the lock is cocked.

It all depends on how far away from the set position the rear trigger can be before the lock will cock freely.
If there is no room above that set position for the sear to cock,,then the assembly is in the wood too deep. If there is some room, then it can benefit from a backlash screw and it's adjustment.

Try pulling the set trigger slowly into position at the same time as the hammer is full back. See if you can determine the position of the set trigger where the sear drops into the tumbler.
(This is easiest to do with the mainspring removed from the lock. That way you're just working with the sear spring and listening for the sear & tumbler click. It takes a few times to get things positioned right to hear the drop of the sear into the full cock notch).
Does the set trigger still have some distance to go before it itself is 'set'. Or do the two things happen at the same instant.

[Acer Saccharum]

You also want to make sure that there is enuff travel for full cock to fully engage!!!! and for half cock, the notch goes in fully!!!!

[heinz]

It helps to realize that the set trigger works by being thrown at the sear.  It does not use the set spring pressure to push the sear aside.  Clearance of the sear above the top of the set trigger is important therefore the set trigger must have some over travel from where the set spring pushes it down to  where the set trigger smacks into the sear.  This is the only way a double pull trigger can be made to work. A single set can be made to work by setting it before cocking but that is a dangerous practice and should be avoided. 
I find it better to remove metal at the back of the set trigger where the set spring rides than from the top of the set trigger because you want to avoid reducing the mass of the set trigger.  In practice you may need to file a bit in both places.

[C Wallingford]

I find it better to remove metal at the back of the set trigger where the set spring rides than from the top of the set trigger because you want to avoid reducing the mass of the set trigger.  In practice you may need to file a bit in both places.
[/quote

I have found that to work as well.  Taking a small amount off the underside of the tip on the spring will also get the same result. As Heinz mentioned you may need to file both areas

[D. Taylor Sapergia]

With a double set trigger, you want the mainspring to have a lot of @#$%/!!.  but the trigger assembly has to be set up so that the back trigger 'floats' and is not pressed up hard against the sear bar of the lock, while the gun is at rest.  This can be accomplished by very judicious filing of the tip of the mainspring, the seat where the spring bears against the back trigger, or by installing a screw from the underside of the trigger plate, to limit the downward passage of the mainspring.  This screw makes the trigger much more adjustable, but has to be set up with the guard off the rifle.