A good .38 Special load is a good .38 Special load no matter how long the barrel is. The barrel length should have no bearing on how you load the ammo, IMO of course.
I have a few favorite loads for the .38 Special, they are:
148gr HBWC over 3.2gr W231
148gr DEWC over 3.5gr W231
158gr LSWC over 4.0gr W231
I usually use a CCI-500 primer and Winchester brass but those loads will work just aw well with most standard small pistol primers and name brand brass. The S&W M14 is a great revolver, good luck with it...