It does not have any bearing on this gun ,but the following may be of interest:
CSN Secretary Mallory and John M Brooke were familiar with the latest ordnance developments abroad, so much so that John Clark &Co had been contracted by either Mallory or Brooke (Although there is no mention of it in Brooke's diaries) to "make an Armstrong gun”. Given the date this can only have been a copy of the breech loader, possibly the 7” 110pdr, drawings of which had been published in “The Engineer”.
This goes some way to explain the apparent anomaly in I.M.Iven's tower ship proposal in that the tower seemed to be too small in diameter to fit two muzzle loading guns - but not if they were intended to be breechloaders.
The company set up two air furnaces and a tilt hammer for the purpose, which were actually used to forge the 40ft wing shafts for Mississippi, and the screw shafts for Louisiana. For this reason, no work, so far as is known was done on the gun.