Loads for 20 Gauge. V.M. Starr says....

[Loyalist Dave]

Less powder, more lead = less MV so less range (so not so very "far" and reduces penetration)...., and reducing the mass by reducing the lead, while adding some more powder, would not kick more, unless you add a substantial amount of powder.  For the thrust pushing the mass of shot out of the barrel also pushes in an equal and opposite direction creating the recoil.  

LD

[Joel/Calgary]

Less powder, more lead = less MV so less range (so not so very "far" and reduces penetration)....,

This presumes that the only factor limiting effective range is penetration.  With unchoked barrels and traditional loads, breech- or muzzle-loaded, pattern density often runs out before penetration.  Traditional load development in unchoked barrels is an optimization problem in penetration and pattern density, with the variables of shot size, shot-charge weight, and powder charge (both granulation and weight), and with recoil one of the limiting factors and a generally inverse (but complex) relationship between velocity and pattern density.  Adding choke into the equation drastically, perhaps fundamentally, changes the relationship between velocity and pattern density, and consequently drastically changes this optimization exercise.

Regards,
Joel

[Loyalist Dave]

This has been "common knowledge" since at least the early 18th century.

Really, well I'm not the first to find fault with proverbs of this sort,

"Although proverbs are generally true, or at least possess some portion of truth; yet nothing is so glaringly absurd, or less founded in rational principles, than that old adage, “sparing of powder, and liberal of shot:” a saying, which is not only in the acquaintance, but in the constant practice of most sportsmen."

Cleator 1767

LD

[Joel/Calgary]

Really, well I'm not the first to find fault with proverbs of this sort

OK, forget entirely about what was reported as observation back when these were the only firearms and components in use.  The same observations about shot size, shot charges, and powder charges are frequently reported today in achieving a balance between pattern and penetration for maximum range in unchoked muzzleloaders.  You can have all the penetration you want, but when you run out of sufficient pattern density, you've run out of effective range.  What is sought is an optimum balance between pattern density and penetration for a particular set of applications.  This more-powder-than-lead for maximum effective range not universally observed, but is common.  As is often observed, every combination of gun, components, and loading technique is unique, and nothing in muzzleloading is universal except variability: what works for an individual works, regardless of what some one else may find.  Naturally, chokes and other devices/methods to tighten patterns change the dynamics of the shot charge - choked guns often shoot tighter with more velocity, at least up to a (somewhat variable) point.

Regards,
Joel