I can’t remember where i’ve heard this but it may just be from a movie or tv show but it was described how if you were to use a gun in a crime it would be smarter to use a revolver just due to the fact that the cartridge won’t be ejected after firing thus it will be harder to track down the gun that was used.
Is there a basis in reality for this, that it’s harder to track down gun crimes committed with revolvers than semi’s?
There is definitely less forensic material to work with if you use a revolver. The casing isn’t that much of an identifier anyway - the bullet is.
Revolvers are more reliable and can fire higher powered cartridges than most semi-automatics can (revolvers can be a .357 magnum, .44 magnum etc. which can kill a much larger animal than a person for example). If you shoot someone with one of those, the chance of death from from a single shoot is a lot greater than a relatively weak cartridge like the very common 9mm semi-automatic.
However, you only get six shots so that is a disadvantage if you aren’t that good of a shot. Larger caliber revolvers are usually quite bulky as well so you lose any stealth factor. There are also plenty of revolvers that fire relatively low-powered cartridges like a .38 (roughly equivalent to a 9mm) or even lower. The lack of ejected cartridges is a side-benefit if you want to commit the perfect crime but it is fairly minor. You can always pick up the shell casings from any gun and take them with you. They fall near your feet. Like silenus says, the bullet itself will have some forensic evidence on it that can usually be tied back to a specific gun.
This point ought tot be obvious to anyone who has the most basic understanding of how firearms work.
Semiautomatic firearms do eject the spent casings after each shot, while revolvers do not. Spent casings found at a crime scene are indeed useful for determining what kind of gun was used, and sometimes even to matching the casings to a specific gun.
I’ve heard of devices that can be attached to semiautomatic firearms to catch the spent casings, but I cannot imagine that any such device would not be awkward and unwieldy, especially on handguns.
As long as you wore gloves when you handled the cartridges.
You get more powder residue in your hands through. But if you’re a regular shooter on the range, dunno how helpful paraffin tests would be.
Many auto loaders fling them a fair distance. Regardless, they are hard cylindrical* objects and are tumbling quickly when ejected. When I drop a nut or bolt it often takes a while to find it, sometimes I never find it, and those don’t roll nearly as well as a cartridge case.
*most center fire automatic pistols use rimless non-tapered cases.
Revolvers lose a fair amount of power to the gap between the cylinder and the barrel. Rounds intended for use in revolver tend to be more powerful, not to deliver more power to the bullet as it leaves the barrel, but to make up for this loss at the chamber/barrel gap.
Of course, as you point out, there are some revolvers that fire rounds more comparable to those generally associated with semiautomatics. It would surprise me greatly if there were no revolvers that fire the exact rounds that are generally more associated with semiautomatics, or no semiautomatics that take rounds more generally associated with revolvers. I’m sure that I’ve specifically heard of a semiautomatic that takes the .357 magnum round.
That assumes that just after you’ve committed your crime, you think you have the time to stay there at the crime scene, and collect your spent brass. Criminals aren’t generally renowned for intelligence, but I think even the dimmest of them would realize the value in leaving the crime scene as quickly as possible, before any witnesses arrive to see (and with modern camera phone technology, take pictures of) them attempting to remove evidence from a fresh crime scene.
So does the casing. At the very least, a spend casing narrows down what kind of gun was used to fire it, to guns known to take the particular round represented by that casing. Patterns of scratches and dents and other marks on the casing can sometimes match it to a specific gun having unique patterns of wear to produce those marks. Depending on the original composition of the bullet, what the bullet hits, and how much damage the bullet takes as a result, it may, in fact, be less useful than a casing for identifying the gun that fired it.
Revolvers are also cheaper than automatics and if you’re just going to use it once and toss it, you can save a bit of money.
The real problem with revolvers is that you don’t look cool trying to fire one sideways. 
But it looks better shot from the hip.
The perfect crime would involve dropping the (print-less, untraceable*) weapon at the scene.
Now they know the gun used - all they have to do is find out who had the gun which hasn’t been seen since reported stolen 30 years ago.
I’ve always wondered if a scuba wet suit and exam gloves whould be enough to defeat the powder test.
Otherwise, get lots and lots of 2nd Amendment plaques and decal and bumper stickers and spend every spare minute at a (100% legal) range - you will light up the test, but have a very good reason.
Use a revolver, then spend 10 seconds with a file and 60 minutes at the range post-crime. The file is for touching up the firing pin a bit, and putting a few scratches in the barrel. The range work will explain any powder residue, and the filework will complicate the shit out of ballistics and matching wear patterns. The more rounds you send down-range post criminal activity, the more the lands and grooves wear and alter markings on the bullet.
Of course you are still going to narked out by your brother-in-law, so don’t commit crimes, kids!
Just use a round lead slug from an aluminum casing. Clean the barrel with mercury and a wire brush, and then show them you use only jacketed slugs from brass casings (supported by your inventory and purchases in the last 12 months.) Silenus’ advice will make a good supplement.
By the way, hire a shooter to do the job for you.
Who will either urn out to be an undercover cop, or turn you in for consideration when he’s been caught for something else.
You can get around ballistics by using one of these.
The drawback being that you have to wear a striped sweatshirt, do this weird dance with your girlfriend where you beat each other up/dry hump, and if you get arrested you have to carry all your stuff in a metal lozenge up your butt for years.
Replacement barrels for many common semiautomatic pistols are readily available.
Drop in a replacement barrel, commit crime while wearing gloves (gunshot residue test), replace original barrel back into gun, dispose of replacement barrel and gloves.
Some pistols really toss brass. One of mine sends empties a good 20 to 25 feet.
What would be the better strategy -
a) Try to defeat the paraffin test (gloves or whatever)
b) Spend time at the range to make sure that you fail the test with a valid reason
I’m sorry-didn’t you mean ‘get to’ instead of ‘have to’?
BTW, wouldn’t a really smart criminal also pitch the gun, regardless of what type used?
All that forensic work on the gun is only valuable if they can use it to trace you, or match it to you if you are stupid enough to keep it.
If you buy the gun in another town/state/country, make sure that you leave no DNA or prints on the casings, and carefully dispose of the gun afterwards, you will not be caught that way.
