Speer lead SWCs are swaged, very soft lead; leading +. Shooting lead is easily done with out leading in your barrel if the bullets fit the gun. Measure the cylinder throats and shoot bullets of that same diameter (if the throats measure .358", size bullets to .358"). Slug the barrel to find the groove diameter, which will normally be smaller than the throat diameter. My .357 Magnum has throats of about .359" and groove dia. of .357" and I can shoot max. loads with plain base lead SWC bullets, @.359", with no leading. With your measurements in hand you can easily order bullets from Beartooth Bullets that will fit your gun.
http://www.beartoothbullets.com/