What's the best 4 - 6 inch .357 / .38 revolver in your opinion? This will be just for range use, and because I think everyone should have a .357

See if you can find a used S&W Model 19/66 or a Ruger Security Six.

GP100?
It's the only larger 357/38 revolver I have any range time with.

Simple, Ruger GP-100. Cheap and reliable stainless steel.

The ubiquitous S&W 686 - preferably a 686-4.

Adios,

Pizza Bob

Kinda depends on use. I love my S&W Model 66 as a mid-sized utility gun, but if I was at the range all day or shooting a lot of magnum rounds I'd say GP100. Also hard to go wrong with a full sized S&W 686.

Ruger GP 100. I prefer it to my Smith Mod. 19 as a utility / range gun.

So far in this thread, only DA revolvers have been mentioned. If you don't object to a SA revolver, consider a Ruger Blackhawk or Vaquero. Both come in blued carbon steel or stainless steel.
The Blackhawk has adjustable sights while the Vaquero comes with fixed sights like the old school Colt SAA.
AFAIK, several barrel lengths are available in both the Blackhawk as well as in the Vaquero. They are: 3 3/4", 4 5/8", 5 1/2", 6 1/2". Also, a "Convertible" as Ruger refers to it, is an extra cost option. It is simply a Blackhawk with an additional 9mm cylinder supplied with the gun.

Right now I have a SS Vaquero in 45 Colt with 4 5/8" bbl. The quality is fantastic and the revolver has performed great so far. But you want a 357 Magnum which is a fine choice since it will give you the option of shooting 38 Special.

Back in the 1980s I remember reading that the 357 Magnum with 4" barrels using 125 JHP ammo had the best track record for one shot stops in police involved shootings. Can't remember exactly where I read that but am pretty sure it was in one of Massad Ayoob's writings.

I like the gp100 and 686 plus. Owned both in the past and regret selling them. I also still wish I had my 66-1 pinned and recessed combat magnum. Next you can get a blacked out Henry X series side gate loading 357 lever gun to complete the package.

I love my 686+ but it is pre lock. I hate the locks. Any L frame Smith is a great gun. First two guns I ever owned were Smith revolvers, M17 and M67. That being said if I could only take one of my 357’s it would be a GP100. My 3 inch GP is my go to revolver but by your criteria I would get the adjustable sight version of the Match Champion and be very happy.

Daughter has a S&W model 640-1. It will get the job done also.

Just a wee bit shy of 4-6 inches. Lol

If you want to use fixed sights at the range a 681 4" is great. Mine is a 681-1.

I also vote for the Ruger GP100. While perhaps not as aesthetically pleasing as the S&W 686, what the GP100 lacks in good looks it more than makes up for in rugged durability. They are engineered well beyond the demands of the .357 Magnum cartridge and their out-of-box triggers are usually quite good. The ability to disassemble the Ruger into its basic sub-assemblies for cleaning and maintenance is also a welcome feature. PS: Ruger offers their model 1740 as a 5" distributor exclusive. They're a bit difficult to locate, though the barrel length sure hits the sweet spot. Enjoy!

GP100 or the S&W 686. Try to handle both and see which fits your hand best, each has a distinctive grip style. Both are tough but my money is on the Smith for ultimate strength. The 686 is based on Smith's L frame, which they also offer in 44 Magnum as the Model 69. Ruger offers their GP100 only as a 44 Special and a bit of an anemic one at that.

S&W’s 686 Plus (7 shot) Performance Center 5” barrel length, moon clip compatible (from the factory) pistol…..

Features:

Performance Center® Speed Release Thumbpiece
Vented, Ribbed Barrel
Interchangeable Front Sight - Orange Front Sight Included
Unfluted Cylinder
PC Tuned Action
Chromed Trigger with Trigger Stop
Chromed Custom Teardrop Hammer
Cylinder Cut For Moon Clips (Moon Clips Included)

I have this pistol and it is more accurate than I am and it can be purchased for less than $1k….

https://www.smith-wesson.com/product/l-frame-11760

I'm in the Ruger GP100 camp. Haven't shot it in a couple years since my son took a liking to it one day. Never seen a new shooter drill a target as he does.....it's a 6 inch barrel.

I already have a S&W 65 (fixed sights) with a 4” barrel that I got for a song. If I had to buy a new 4” 357, I’d go for the Ruger.

adjustable sights
Built like a tank

Reading the title I was going to say a Mark I Desert Eagle.

I'll go with a GP-100 with an SP-101 a close second.

I hate stainless, and don’t see a point in buying new ever. I would find an older used S&W ( I like the more handy and light K frame compared to the L or N, but all have advocates) and have at it.

Even when I had some magnum guns, I most shot 38 special and as such the K frame worked just fine.
If you prefer stainless ( with the exception of living in close proximity to a swamp or salt water it is not a great advantage over blue, and blue looks so much better!) go ahead, but to me nothing beats a 4” model 19. I would suggest the 4” over the 6” as it is more versatile and can be used as a ccw which the 6” really is not realistic for