Forestclimber,
The WPF marked on the muzzleface stands for West Point Foundry where the gun was cast, and I believe the M.S. Co stands for the Midvale Steel Company, which manufactured rifled sleeves for some of these guns (this one has 24 groove right hand twist). The No. 30 is the Registry number, the weight is 16,010 lbs, and the year 1885. I don't know what the letters F.E.H. represent, the inspector of this gun is identified as RB on the National Registry.