All of the "Super Mag" calibers typically used in the Metallic Silhouette game, as well as in hunting, are known to slightly gas cut top straps in revolvers. Us steel silhouette shooters know this well. The calibers are: 357 Maximum, 375 Super Mag, 445 Super Mag and 414 Super Mag. The cutting stops somewhere in the range of .002 to .006 inch depth I believe, which is about the typical barrel to cylinder gap in many quality revolvers. Actually, gas alone nor powder granules alone will cut steel. It is a combination. Powder propelled by the hot and high velocity gases burning does the cutting. But most revolver makers know this and beef up the guns that chamber these calibers.
Wayne