Ok I recently purchased an older Model 28-2 that I believe was made in 1967 or 1968. I bought it from a LGS and after I got it I noticed a rattle. It is more of like a sliding metal sound in that if I tip the muzzle down I hear something slide and if I raise the muzzle up it slides back, whatever “it” is. I took off the side plate as I’ve done before on several other revolvers and I took the hammer block out and it still made the sound. I took off the cylinder as well and the grips of course and it still makes the sound. I cannot see what it is but I can hear it. I’m thinking maybe it’s something under the rear sight or in the trigger area but I can’t tell. I tried to take the rear sight off but the front screw is very shallow and I can’t get it off. Thanks and any help would be appreciated.