My reference to the velocity issue was borne from experience with the Marlin Camp 9 and Camp 45(not computed internet graphs).
Years ago I had the Camp 9 and shot tons of Federal 9BP HP through it. Through a chronograph it showed we lost around 40-70 fps from the Marlin compared to a pristine little S&W 39. Likewise my Browning P35 shot a little "faster" than the carbine. I was very disappointed until a co-worker agreed and brought his then-new Camp 45 out, and it scored absolutely single-digit fps increases over the 1911s we had on-hand. (This was the 80s, I had no Excel software on-hand).
Then at least, factory pistol ammo was apparently loaded with powders designed to fully burn within a very few inches of barrel - the longer carbine tubes had little or no flash, indicating to our pseudo-scientific minds that the gas-expansion had fully occurred long before the bullets left the muzzle, which essentially meant the rifling began to drag on the bullets after full gas expansion had occurred.
The effect was not not there of course with a 357M and 44M carbine at hand, wherein much slower powders were in use, utilizing all the barrel length (and more) while the powder was still burning - and giving comparatively huge fps advantage. Ruger themselves proved the concept with 22LR barrels, wherein the optimum velocity can be achieved at around 16-17 inches, and more barrel (like my 22" Cooper) may provide realized accuracy but zero additional velocity over a 17-incher. But things are almost always different with rimfires... YMMV.