Set your trigger assembly in a machinist's vise, as if it was installed in your rifle. Set the triggers. hold a screw driver between your thumb and forefinger, by the end of the handle. Hover the bit of the screw driver over the back trigger's bar, and fire the triggers. The back trigger bar will strike the bit of the screw driver. It should have enough force to make the screw driver jump. If so, it should fire the lock. If not, the spring may be soft. Re-hardening/tempering will take care of that.
If everything works as I have described out of the gun, but doesn't fire the lock when installed, I suspect that when you set the triggers, the inlet is stopping the trigger's mainspring from rising to it's zenith, thereby diminishing it's force downward on the trigger. That spring requires clearance. From your photos, I can see that the rear trigger rises sufficiently to fire the lock. Another issue may be that your full cock notch requires some stoning/polishing, if it is hard to trip the lock when hand held out of the stock.
Everything from your images appears to be fine. Filing out the mainspring stop on the trigger plate as illustrated above, will cause the rear trigger to be held high, interfering further with the lock's sear.