That's all I ever use, either Berrys or Rainier 125 or 158 gr., so much easier to clean and I can't see the harm. I can load a box for about $9, if I buy by the thousand. I load mild stuff in 38 and use them in my Python, PP, and 2 Smiths. Been doing that for many years.
If you intend on shooting MANY, MANY thousands of rounds, FMJ will eventually wear the barrel and accuracy will degrade over time.
You can shoot lead bullets until the action of the gun is completely worn out and the barrel will likely be still like new.
However, few shooters will shoot enough ammo for FMJ to have any noticeable affect, so have at it.
If you want defense ammo, the FMJ is a very bad choice. The bullet tends to over penetrate, and doesn't do enough tissue damage to reliably stop an opponent.
I like the rem or win 130 grain fmj 38 spl loads. I shoot them in my colt PP and colt 3 5 7. I also like shooting the 158 grain LRN 38 spl. all standard pressure loads. for defense I like the 125 grain JHP 38 spl +P.
I shoot FMJ rounds in my PPS all the time when target shooting. A lot less fouling, in my experience, than lead rounds. Hornady 110 gr Critical Defense for concealed carry, tho. Just an after thought: what type of round was commonplace for police work when my PPS was built in 1922?
I assumed FMJ would wear the barrel more but I won't shy away from them, as I always have, if I can get a good deal on FMJ bullets for reloading. But I will still mainly use lead bullets for my old Colts.
Elmer Keith claimed that 5,000 jacketed rounds would wear out an M1917 barrel. IIRC, General Hatcher shot some S and W M1917 guns to destruction during WWI and found that the barrels were shot after 5,000 rounds. This of course, was almost a century ago with corrosive primers and early smokeless powders. I would think that contemporary standard pressure ammunition would be somewhat easier on revolvers, which means you could probably shoot more jacketed rounds without damage to your firearm. Nevertheless, I have grown old and experienced enough to not doubt Keith, in contrast to his later colleagues.
Like Mr. Oyeboten, I rarely shoot anything but lead through all my handguns, but I occasionally will shoot a box or 2 of the .38 Special FMJ ammunition in order to get the fired cases. I have never seen any damage resulting from this shooting.
If you can afford to shoot 5,000 FMJ factory rounds through your Colts, then you can probably afford to rebarrel you revolver if the need arises. I wouldn’t worry about the occasional box of FMJ loads.
When the K frame S&Ws were issued in the tens of thousands to USAF and US Army aviators and aircrews, training was done with military FMJ. The training wepons fired uncountable numbers of rounds and were only rebarreled after between 40-50,000 rounds and some even longer. I don't think any of us are going to have to worry about the FMJ slugs. And they were all off the production line revolvers. The Army also issued the OP and DS and even some 4" and 2" Cobras which were also used with FMJ ammo. I was once issued a WWII Victory model, which I stupidly turned in upon transfer.