I am new to the forum but not to shooting & collecting Lugers. I bought a 1917 Artillery in 95% original finish about a year ago & began shooting it after firing aprox 500rds thru it of Win.115gr factory amo the firing pin retainer blew out the rear of the breechblock. I know this is a original gun with all matching #s as far as I can tell. In all my years of shooting Lugers I have never encouterd this. I am truly puzzeld? Why? Bogus gun? Defective firing pin retainer? Any info would help!