Is that what the Mark IV in .38 takes, .38 S/W long? .38 special won't work?
T
You'll find out real quick that .38 spl won't work in a Mk IV; the case is probably about 1/4" too long for the cylinder. .38 S&W can be difficult to find. For years, I've been using the same steel-cased ammo I'd bought in around 2000, but I did score 50 brass-cased Remington rounds at Bass Pro last weekend. Pricey, though.
My story is the opposite of trippingpara's; I got into reloading after I finally found a .455 earlier this year, as ammo in .455 Webley is unobtainable for a decent price. Both revolvers are fantastic shooters, though fit and finish on the .455 is far superior. My Mk IV is pretty rattly.
I've posted this before, but...
The Mk VI was my holy grail, but the Mk IV has a better story. And it means more to me.