After working with CampbellClan's Reading County rifle, and the Siler-locked Tennessee I also have in progress, both of which have set trigger assemblies from Davis, something I've noticed before is now confirmed as fact in my experience and I will pass it along to others contemplating either building or ordering rifles equipped with set triggers.
Unless built from kits, which are available through Track Of The Wolf and most likely other suppliers as well, and which have squared castings gates attached to the upper edges of the as-cast trigger bars, you are liable to run into difficulties if using Davis set triggers in combination with L&R and possibly other locks.
Reason being, on the L&R locks I've actually worked with (both Manton and Durs Egg, Dickert, American Classic, Leman/English, Queen Anne, Bedford....), the sear arm that the trigger bars engage sits approximately 1/8" to 3/16" above the lower edge of the lockplate. In contrast, on the various Chambers locks (which include the Silers), and the few Davis flavors I've worked with, the sear arm is very near the lower edge; in fact on a few locks I've had pass through my hands the lower corner of the sear arm actually just faintly protruded beyond the edge of the lockplate. This is incorrect geometry but it does illustrate how near the lower edge of the lockplate the arm is normally found.
1/8" to 3/16" higher, above both the lockplate's edge and the bars of the two triggers on a set trigger mechanism, is an awful lot when you consider the trigger bars having to reach up that far to engage the sear arm, and that because the bars are travelling upward in an arc, not straight up, they're putting pressure on the sear arm from an angle rather than directly up. You don't notice when the rear trigger is set and it "flicks" up to snap the sear loose from the full-cock notch. You notice big-time when you try to use the front trigger, alone, and after what feels like a mile of take-up the trigger bar engages the sear arm and you try to squeeze off a shot.
There is no practical way to position the trigger mechanism any higher in the stock, so as to move it and its trigger bars closer to the lock and its sear arm. Study the longrifles I build, that have set triggers. I don't leave excess wood below the lockplate. My guns don't have any "belly" to them. Short of inletting the triggers deep into the wood, instead of flush with the bottom of the stock as they ought to be -- the situation is what it is.
This "situation" becomes worse on halfstocks, because whereas on a correctly-proportioned fullstock there is 1/8"-3/16" of wood between the bottom of the barrel channel and the ramrod hole/groove, on a halfstock there really needs to be a full 1/4" to accomodate the thickness of most underribs. On one halfstock that I'm presently building, even though I'm using a Chambers/Siler lock with its lower-placed sear arm, I had to use a Davis lock assembly that is one of a batch made up special for Troy Roope at Stonewall Creek Outfitters; the supplier built up some Davis kits and left the casting gates intact to extend the trigger bars upward almost 1/8". The only other Davis option would be their "Deerslayer" set trigger assembly, intended as an aftermarket replacement for T/C and Italian triggers and accordingly made with taller trigger bars.
In future, if an L&R lock is called for on any style of rifle, or I'm building a halfstock with a somewhat deeper belly (such as any of my western trade rifles), I'll either be installing the Davis Deerslayer unit or an L&R set trigger mechanism. L&R leaves their trigger bars significantly higher than Davis does, apparently having gotten the memo that it is far easier to remove metal, if necessary, than it is to add it to tempered-steel trigger bars. If I have to heat, solder/weld, grind, and re-temper the trigger bars to get the things to work in the gun I'm building, I might as well have bought a Davis kit trigger and started from scratch.
Set triggers are a joy to use (for those who like them) but can be something of a PITA just to position and inlet correctly, and when all is done and you discover the trigger bars can't reach QUITE high enough to reliably (and smoothly) trip the lock -- well, I'm sure I've contributed heavily to global warming, at least over the midwestern United States, due to the ozone-melting profanity that's liable to escape the confines of my shop. And I thought that when I consistently have this problem of too-low trigger bars for the lock they're being used with, someone who hasn't run into this over and over again might appreciate the heads-up as he contemplates which parts he wants on that upcoming dream rifle.
Great information, and thanks. Its very rare that a master will share any information such as this, especially on a public forum. I respect and appreciate your wisdom and artistry, and the fact that you are willing to explain and share these..'stumbling blocks' that most would never think about before they hit the roadblock.
What Mike said, I have run into that problem more than once, welding triggers IS a PITA. Thanks for getting this info out, Mismatched tgr/lock combo can cause plenty a extra labor. ....Tom
One semi-acceptable solution to the problem is to remove the sear from the lock, clamp the forward portion (sear nose and pivot hole) in a vise, and heat the arm and rear portion of the sear red-hot enough that they will bend down till the sear arm is about flush with the bottom edge of the plate. If one MUST have Davis triggers and a lock with a sear placement that's not compatible, this might be the only fix short of welding on the trigger bars. However, later on, if the gun is sold or someone not familiar with the problems that arose in building it should remove the lock, there's that obviously-heated-and-bent sear showing up like a sore thumb, and the first (and logical) assumption is that the lock got worked over by a chimp with access to oxy-acetylene.
Building up the trigger bars on Davis triggers presents another issue, no matter how perfectly the work might be done. The prime reason that Davis triggers are used is that either the gunsmith or the customer who has ordered the gun specifies that brand. Davis is well-known for being about the best commercially-available triggers that money can buy, and much the same as some customers INSIST on a Green Mountain barrel, Siler lock, and high-grade curly maple stock (because all that fits their limited notion of what is "best"), they likewise must have Davis triggers. The problem is, what makes Davis units special is the quality of the steel, heat-treating, and finish in their construction. Weld a tab atop one or both trigger bars, then grind and polish and re-temper, and though the job may be very well-done it's no longer truly a Davis-built trigger -- it's a Davis modified by someone who may or may not have been at the top of his game when he did the work.