.38special and .357magnum have the same bore. It's the length that's different.

Same lead. Even the primers are the same. But you really want to use small magnum primers on .357mag

I shoot .38special wad cutters in my .357mag all the time or bulk .38special because it's usually a good bit cheaper.

Also, .357mag uses different powder if I'm not mistaken.

I personally would never by a .38special revolver unless it was a smoking hot deal. Not all are +p rated and all .357mag revolvers can shoot all .38special ammo from wad cutters to +P to +P+.

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SW Sigma 40VE, 22a, M&P 15-22