My sister has our Dad's old 38 Special CTG loaded with +P ammo. Is it safe to use +P in this gun? The barrel is marked "38 S&W Special CTG" and the serial number is C697291. Also, what would the year of manufacture be?

Your Model 10 M&P would be from about 1963-64. +P loads won't hurt it, but I'd use regular .38 Special ammunition if for no reason other than ammunition cost. +P buys you very little in performance, and paper targets, cans, and bottles won't know the difference.

CTG is just the abbreviation for "Cartridge."

+P for carry (a cylinder full a couple of time a year @ the range) and regular pressure for practice.

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Old Cop
LEO (Ret.)