Here's a question...which generates more barrel heat (heating a barrel quicker): assuming the same powder and charge, a lighter bullet traveling faster (approx 2900 fps), or a heavier bullet traveling slower (approx 2400fps)?

I would suspect the heavier bullet.....same charge with heavier bullet equals more pressure which most likely means more heat.

I think it is the burn rate and amount of powder.

50 gr of powder makes more heat than 25 gr assuming the same powder.

Faster burning powder puts all the heat in the first 10 inches of the bbl. Slower burning powder puts the heat in 20 inches of the bbl.
The numbers are used for illustration only, the real numbers change with the burn rate if the powder.

I have no data to prove or disprove those statements.

Lots of variables so - Can't speak directly to the question but... To address one of the variables - As a high volume pistol shooter in the past I can say that some powders burn much hotter than others. I shot fast burning powders in my 9mm and .40 pistols for years and found Titegroup burned Much hotter than Solo 1000 - both being very fast powders. Barrels last a lot longer with Solo 1000 when the average course of fire was 25-30 rounds fire very quickly... The Solo is a single base powder and the Titegroup is double base.

From wikipedia:

Double-base propellants
Main articles: Ballistite, Cordite, and Smokeless powder

To further increase the energy of smokeless powder, nitroglycerin can be added in amounts up to 50%. These powders are called "double-base powders", since both their main components actively produce energy, and they have similar basic physical properties to single-base powders. The nitrocellulose serves to desensitize the highly unstable nitroglycerin, preventing it from detonating as a high explosive, and the nitroglycerin gelatinises the nitrocellulose and greatly increases the energy density of the resulting powder. Double-base powders burn faster than single-base powders of the same shape, though not as cleanly, and in general the higher the nitroglycerin content of a powder, the faster the burn rate.

In artillery, Ballistite or Cordite has been used in the form of rods, tubes, slotted-tube, perforated-cylinder or multi-tubular; the geometry being chosen to provide the required burning characteristics. (Round balls or rods, for example, are "degressive-burning" because their production of gas decreases with their surface area as the balls or rods burn smaller; thin flakes are "neutral-burning," since they burn on their flat surfaces until the flake is completely consumed. The longitudally-perforated or multi-perforated cylinders used in large, long-barreled rifles or cannon are "progressive-burning;" the burning surface increases as the inside diameter of the holes enlarges, giving sustained burning and a long, continuous push on the projectile to produce higher velocity without increasing the peak pressure unduly. Progressive-burning powder compensates somewhat for the pressure drop as the projectile moves down the bore and increases the volume behind it.)

OR - Single-base powders get energy from Nitrocellulose. Double-base powder use both Nitrocellulose and Nitroglycerin.


I THINK.....

Double base powders are more temp sensitive.
Double-base powders have a flatter pressure curve.
AS the nitroglycerin burns quicker, and the nitrocellulose slower.
SO Loaded to the same velocity, peak pressure is less as is peak temperature.
SO Loaded to the same pressure, velocity is more due to longer burn.
You can get more velocity at max pressure at the expense of greater throat erosion as the peak pressure is maintained longer
But, if you load equal velocity the erosion is less since max pressure and temp are both less.

And IMO add this = the closer you load to max loads or above max load the more apparent the difference is between SB and DB powders and the faster your barrel loses accuracy due to throat erosion using either.

Please note that not only am I not qualified to make a scientific assessment of what I have just written and I have never stayed at a Holiday Inn either.....

My .02, YMMV, yada yada yada