Dry Firing Jump

[X-man]

The firing pin is held back and released by the trigger.
Therefore, the trigger directly affects firing pin impact. It affects the amount of pin fall on release, as well as friction in this fall(as is solved by the Kelby replacement for Jewells with certain actions), and yes lock time for sure. Bolt TURN/POSITION is also affected, and you should mind the consistent stopping of bolt turn. Don't assume it.

If, with a given trigger(not model but actual), you have not set the pin strike for best grouping, you probably have not reached the best from your gun. I have whitnessed a perfectly firing mis-setting of a firing pin cause ugly performance. Flyers..

This is an area rarely looked at or discussed. I believe there is a lot to learn here.
Ever wonder why we're left to swap primers trial & error during load development? Why a primer that sucked for you works great for someone else in the same cartridge & load?
The answer is primer striking. Well actually, the ABSTRACT is primer striking..

Some interesting comments and observations.

Though I have no idea why I have rifles that jumped while dryfiring (with a factory trigger) that are stone still after the installation of a Jewel.

I believe consistent ignition is paramount so I have my gunsmith spend a lot of time honing the pin bore and making perfect all contacting surfaces of the pin and bore.
Though I can't prove a loss of accuracy, the buggered up look of the J-lock pin and spring setup wreaks of bad workmanship and poor precision. I replace it with a quality spring and assembly, then have the pin bore blueprinted.

 

[Bart B]

I well understand the influence of trigger hardware effecting the firing pin's start up and final function characteristics as well as what's needed for consistant primer detonation by the firing pin. But enough of this "off topic" pazazz. Back to the OP's concern of seeing his reticule jump.

As I stated before, as long as the reticule returns to the same place in the scope after each operation of the firing mechanisms, there should be no concern. I even suggested a way of testing it for repeatability.

Some reticules will vibrate like a string on a guitar; fixed at each end and bowing a bit in the middle. And their mount stays securely in place. Nary a problem if they're repeatable in going back to their resting point.

 

[Bart B]

I had a very similar problem with my 6br, . . . .now it shoots 1/3moa at 600yards.

That good it that's the worst it shoots. 'Specially when all the record setting benchrest guns shoot near twice that at their worst.

 

[X-man]

That good it that's the worst it shoots. 'Specially when all the record setting benchrest guns shoot near twice that at their worst.

2 inches is very good at 600 yards...At least it is in F-Class.