.38 vs. .357 Mag.

[Pecci]

Which one is more inherently accurate?

[Almtnman]

Due to the difference in recoil, I would have to give the nod to the .38. 

[Mikey]

Pecci:  almtnman has a good point but it just depends what you want to shoot from the revolver.  38 Spl wadcutters are target accurate from most 38 Spls and also from many 357s.  Many 357 magnum loads are also target accurate but recoil may be a factor for you as almtnman provided. 

It simply depends on what you want to use the revoler for:  sometimes hunting but mostly target/indoor range work gets a nod for the 357 due to its overall hunting capability;  mostly range/accuracy shooting with some personal defense thrown in would probably go to the 38.

Again, it depends on the use you intend for the gun.  HTH.  Mikey.

[williamlayton]

A .38 super would be good.
Blessings

[HiPressure]

I'd have to say that in a good quality handgun both are more accurate than the average person can shoot. Recently, I spent a day with a fellow who invited me to try his Ransom Rest. No hesitation there! Since he has inserts for the common S&W revolvers I dragged a selection out see just how well my handloads were doing. The results floored me, I never realized a 357 J-frame could shoot that good!  As stated by others here, I think the 38 SPL gets the nod overall just because in most revolvers it's just so danged easy to shoot without getting a nasty flinch. Shooting a low velocity target wadcutter load out of a L-frame will give you not much more recoil than shooting a 22LR. Almost as much fun, too!
HP

[Jerry Lester]

I'd have to say that in a good quality handgun both are more accurate than the average person can shoot. Recently, I spent a day with a fellow who invited me to try his Ransom Rest. No hesitation there! Since he has inserts for the common S&W revolvers I dragged a selection out see just how well my handloads were doing. The results floored me, I never realized a 357 J-frame could shoot that good!  As stated by others here, I think the 38 SPL gets the nod overall just because in most revolvers it's just so danged easy to shoot without getting a nasty flinch. Shooting a low velocity target wadcutter load out of a L-frame will give you not much more recoil than shooting a 22LR. Almost as much fun, too!
HP

Right on the money. I've fired literally tens of thousands of both calibers in quite a few revolvers, as well as rifles. The one thing that hasn't been mentioned here is the factor of if you're shooting 38's from a 357 chamber. I have seen 357 chambers that were reamed a little oversized that tended to cause 38 loads not to shoot to their best potential. Other than that, I haven't seen a noticable difference in either caliber as far as accuracy when both were loaded with care, and brass is properly prepared for loading.

[Old Griz]

I have found that shooting .38s in a gun chambered for .38s (only) are verrrrry accurate. I have a S&W 10 that's scary it shoots so good.

On the other hand, .38s fired from a .357 are not going to shoot as well as .357s fired from the same gun. That little jump does make a difference. However, when I shoot .357s in my SA Blackhawks and DA Colt, they do pretty darn good, too.

Given a choice, I would rather shoot .357s. I'm a crazy old fart that loves the recoil. (Actually, my favorites are .44 mags, but that wasn't an option in the original question, so please ignore this remark)

So in truth, I don't know which one is more accurate, but I'd trust my life to either of them. I know it's gonna go where I point it.