.38 special
Stay away from the "+P" ammo
38 caliber revolver ammo
A Colt police positive ,32 with that serial number was made in 1909.As far as ammo,you can check with any gun shop.
You need to contact Colt
You need to contact Colt for a correct answer.
Gun shops, gun shows, on line, pawn shop,
You need a good gunsmith.
if it's a revolver......32 cal revolver ammo if it's a pistol......32 cal pistol ammo
it's possible your colt was made for 38 S&W cartridge. that cartridge is smaller in length than the 38 special cartridge. try fitting a 38 S&W cartridge.......
.32 S&W Long If that doesn't work you will need to compare the serial number and figure out the manufacturing year, there were minor variations depending on which decade it was made; and of course there are a handful with aftermarket modifications. But the 'police CTG' models should have no trouble using .32 S&W Long. It should also be interchangeable with other ammo of the same size such as: .32 Colt New Police .32 Colt Police Positive
Colt .38 New Police was the Colt name for .38 S&W. Same ammo.
Have it checked out by a good gunsmith.
If the gun is .38 special and so is the ammo, then you're okay. You should be concerned with the gun it's self though. Take it to a gunsmith to be inspected if you're unsure of the gun functioning properly.