It seems to me that a semi-auto loses some energy in sending the projectile down range by also sending the slide back against the springs. There has got to be some energy that would have been used on the bullet used here instead
You're confusing energy, force, and momentum...
The energy in the powder is changed from potential energy stored in the chemical bonds of the powder into kinetic energy of the bullet and heat...energy cannot be created or destroyed, it just changes form...nothing is lost, though much is 'wasted' in the form of heat that produces no useful work in sending the bullet downrange.
Sidenote:
If ALL the energy in 8 grains of Unique could be instantly released, then kB! would become ktB!!!!! (as in kilotonBOOM, if you catch my drift)
The force which acts on the slide and sends it back is the reaction force from the bullet/powder/gas moving forward...Newton's third law...there is nothing lost by having the slide moving backwards...the force backwards is exactly equal to the force forwards...which brings us to momentum.
Momentum is mass x velocity; like energy, momentum cannot be created or destroyed, and the momentum of the bullet is equal to the momentum of the gun moving backwards...the bullet has a small mass and a high velocity, which equals the large mass and low velocity of the gun.
Which brings me to the qualified answer to the question, which is that regular production revolvers are more accurate than regular production
recoil-operated semiautos.
REVOLVER:
If the barrel axis is co-axial to a cylinder charge hole axis, and the forcing cone and cylinder exit holes are square to those axes, the only accuracy-affecting factor is the
free play movement of the cylinder at lockup...we'll assume for both revolvers and autos that the cartridge in the chamber or cylinder has equal free play.
Revolvers use chemical energy converted to kinetic energy to actuate their mechanisms...in other words, your finger moves.
R-O AUTO:
Free play movement occurs at the muzzle between slide and barrel
Free play occurs at the breech between slide and barrel
Free play occurs between slide and receiver
This is necessary of course because r-o autos use momentum to actuate their mechanisms...in other words, the slide/barrel moves.
(Notice that blowback autos still have two sources of accuracy-robbing movement)
* * *
The second factor is the ignition mechanism.
Any decently made revolver has a mechanism that is the result of centuries of refinement, and would makes a Swiss watchmaker drool on his Rolex (Ruger and your liability lawyers, go sit in a corner). They can have small bearing surfaces because recoil doesn't affect those surfaces.
Any auto has the problem of a slide returning to battery and slamming to a stop...a sudden impact that affects the trigger/sear/hammer relationship...the surfaces can never be as small as a revolver's, and hence never as crisp.
This of course is only an aid the the shooter and has nothing to do with inherent accuracy.
* * *
SO,
Revolvers have one source of accuracy robbing movement, which in total is usually less than the three of a r-o semi-auto.
Revolvers have much crisper hammer releases.
Given equally well-made barrels, an off-the-rack revolver is more accurate than an off-the-rack auto.