I have two .357 max ruger blackhawks and a NEF handie rifle in the max, As to the flame cutting he topstrap as long as you don't use lite bullets this dosen't happen. The handie rifle can be reamed from a .357mag in about 5 minutes to a max cost less than 50 dollars, The rifle itself is 250 or less, thats half or less what your gonna pay for a TC. Mine shoot inside of 1.5 inches @100 yards.
Standard .38/.357 dies work for it, I used Lee 4 die carbide set.
As for bullets, all the pistol bullets work fine as do some of the .35 cal rifle bullets. Jacketed or cast I use both. Most seem to prefer 180gr and heavier bullets, Lots of powders work but IMR 4227, AA 1680,and RL7 seem to be very popular.
You can load them up hot, like 158 gr SPs at 2500FPS or better or cat sneeze loads of 125gr LRN at 900fps.
It will also shoot .38 specials and .357 magnums. Mild to wild the maxi ofers it.
My favorite load is IMR 4227 under a 180gr LBT style LFNGC hardcast @2000FPS very accurate and knocks whitetails silly.
Its my favorite hunting rifle, If you wonder up to the H&R NEF forum you'll see its very popular there. As far as who make them today, I don't think anyone dose except barrells for a TC, Gettig a H&R/NEF .357mag reamed is a easy with hand tools job you can do at home. Used pistols can be had but they are pricey.
Get a .357 handi and ream it out, You'll like it. If you don't go look in the NEF classifieds I gauntee you won't lose money on it.