Could be ammo related. May also be the B/C gap is too tight...the gap between the barrel and cylinder face should ideally be around .004" - .006".
If it's too tight due to end shake or improper fitting, the debris on the front face of the cylinder can rub on the end of the barrel/forcing cone area, and cause the cylinder rotation to be impeded. (Also, check for shooting debris build-up in these areas, and check to see that the cylinder assy and yoke barrel are clean and properly lubricated.)

If the gun is new, there can sometimes be too little end shake on the yoke barrel, which can also cause binding. (not enough space for the cylinder assy components to function/rotate properly)

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Ret. LE, FA Instr, S&W Armorer