Some ideas seem to have been shared amongst the old shooters for quite a long time. One such is the belief that if reloading is delayed after a shot, cool air will get into the barrel and cause condensation, thus dampening and weakening the powder.
From 1727, Markland:
"SEE: A Cock-Pheasant sprung! He mounts_he's down!
Trust to your Dogs! Quick, quick_Recharge your Gun
Before the Air gets in and damps the Room!
The Chamber hot will to the Powder give
A Benefit, and will the same receive.
The open Touch-hole, too, if haste you make,
Its little fatal Train will freelier take.
Oft have I seen th' undocumented Swain
Feath'ring the Parts and cleansing off the Pan
Until the cooling Piece grew moist again.
The tardy Charge wiped that cold Sweat away_
And grew itself half Wild-fire by the way.
A Treatise on English Shooting; by George Edie, Gent., 1773:
"Observe after a fire never to blow through the barrel, but charge again immediately while the inside of the barrel is hot and dry ; by this method of immediate charging, a gun seldom hangs fire, and carries much smarter and better ;"
An Essay on Shooting, Wm. Cleator, 1789
"When the piece is fired, it should be re-loaded immediately, whilst the barrel is warm, lest by delaying it, a certain moisture should be formed in the barrel, which would retain a part of the powder when pouring in the charge, and hinder it from falling to the bottom.
"Powder, also, as already mentioned, will imbibe moisture from the air, and therefore it is of additional advantage, to load the piece whilst the barrel is warm, because some part of the moisture will be thereby evaporated."
Spence
From 1727, Markland:
"SEE: A Cock-Pheasant sprung! He mounts_he's down!
Trust to your Dogs! Quick, quick_Recharge your Gun
Before the Air gets in and damps the Room!
The Chamber hot will to the Powder give
A Benefit, and will the same receive.
The open Touch-hole, too, if haste you make,
Its little fatal Train will freelier take.
Oft have I seen th' undocumented Swain
Feath'ring the Parts and cleansing off the Pan
Until the cooling Piece grew moist again.
The tardy Charge wiped that cold Sweat away_
And grew itself half Wild-fire by the way.
A Treatise on English Shooting; by George Edie, Gent., 1773:
"Observe after a fire never to blow through the barrel, but charge again immediately while the inside of the barrel is hot and dry ; by this method of immediate charging, a gun seldom hangs fire, and carries much smarter and better ;"
An Essay on Shooting, Wm. Cleator, 1789
"When the piece is fired, it should be re-loaded immediately, whilst the barrel is warm, lest by delaying it, a certain moisture should be formed in the barrel, which would retain a part of the powder when pouring in the charge, and hinder it from falling to the bottom.
"Powder, also, as already mentioned, will imbibe moisture from the air, and therefore it is of additional advantage, to load the piece whilst the barrel is warm, because some part of the moisture will be thereby evaporated."
Spence