Howdy Jeffly,
As to whether a .357 rifle will shoot a .38,it depends on the rifle. It's not the shooting that's the problem,it's the feeding of the rounds from the magazine to the chamber. Cartridge length seems to be the determining factor. Some rifles will feed both .38s and .357s without a hitch,and some won't-including rifles of the same make. A good gunsmith can sometimes make a balky rifle feed both types of ammo.
Barrel length,like pistol length,is more of a personal preference than any competitive advantage. I shoot a 24" Marlin,but I also own a 20" Rossi 92.
Bellicose Bill
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