I have thought this convergence issue many times in terms of first steps of regulation. Basically, the mechanics of 'convergence - recoil - velocity' are fairly straightforward, or, at least understandable.

Is there any idea of collecting a simple database of relevant variables for example here in this forum. Many of you have regulated doubles from which you know the bullet weight & velocity and the horizontal spread of the POIs between the barrels. Then if you also measure the convergence of the bore axes, this combination of variables would give the very basics of the horizontal regulation of those rifles.

This database could then be used (instead of quesstimation) as a reference when assembling the barrels of a home built DR for the first shots.

Of course the database could also give calculations of recoil velocity if you include the gun and charge weights etc. in variable list. I don't know, however, how much added value that brings to the system, but it might be worth trying.

I guess this kind of database would soon show, if it is useful at all. We do not have to wait the results from newly built DRs, but we can start to explore the data as soon as it gathers. It will fast show if there are certain regular patterns in the behavior of those variables in well regulated doubles.

To my mind this is not even sensitive to the used donor and its breadth at the breech (distance of firing pins). A wide actioned DR is wide at the muzzle end too, and vice versa. It is the convergence at the length of the barrel that counts. Am I right?

Any thoughts of this whole thing?

Regards,
Saku