Firing Procedure for the 16"/50 (40.6 cm) Mark 7

Updated 10 July 2005

Verbatim from NAVORD OP 769, Page 2-21:


Breech Opening:  The gun captain opens the breech, wipes the mushroom, and looks through the bore to make sure that there are no gases or burning remnants from the preceding round left in the gun or breech.  He then announces "bore clear", depresses the bore clear switch momentarily, and trips the gas ejector valve.  For the first load, the gun captain must manually disengage the salvo latch.

Priming:  As soon as "bore clear" is announced, the primerman inserts a live primer into the firing lock.

Cradle opening:  After a projectile has been lifted into (and latched in) the cradle and the bore clear switch has been depressed, the cradle operator depresses the foot pedal (unlatching the cradle) and positions the cradle control valve handle at LOWER CRADLE.  The cradle then rotates to lower and to enter the spanning tray into the open gun breech.  The cradle cannot be lowered until the bore clear switch has been depressed because of the cradle interlock portion of Ready Light Circuit 1R.

Projectile Ramming:  After the cradle assembly is spanned (containing a projectile), the rammer hand lever is moved toward RAM and the projectile is rammed into and seated in the gun.  The hand lever is then moved toward WITHDRAW.  The upper powder door is opened simultaneously with these ram and withdraw movements.

Powder transfer:  After the rammer has been withdrawn, the powder car hoisted, and the hoist upper door opened, the hoist operator dumps the lower car tray.  The upper powder door cannot be opened, because of the powder door interlock portion of Ready Light Circuit 1R, until the rammer has been withdrawn after projectile ramming.  The three powder bags roll down the open door (which forms a shelf between the powder hoist trunk and the spanning tray) and are guided into the spanning tray by the gun captain and cradle operator.  These men spread the bags (two forward and one aft) to make a space wide enough for the three bags still in the powder car.  These remaining bags are then dumped by the hoist operator (who has lowered the powder car) and are guided into position on the spanning tray to be rammed into the gun's powder chamber.

Powder ramming:  After all six powder bags have been transferred to the spanning tray, the rammer hand lever is moved toward RAM and the bags are rammed into the gun's powder chamber.  The hand lever is then moved toward WITHDRAW.  The upper powder door is closed simultaneously with these ram and withdraw movements.  As soon as the rammer is fully withdrawn and the upper powder door is closed, the cradle control valve handle is positioned at RAISE CRADLE.  The cradle then raises and retracts from the gun.  The gun captain then closes the breech and positions his ready switch at READY.

Firing:  When the breech is closed and the gun captain's ready switch is positioned at READY, the firing circuit closed within the turret, and the turret officer's selective switch turned to DIRECTOR, the gun can be fired electrically by remote control.  During recoil and counterrecoil, the salvo latch is tripped automatically and the breech can be opened.  The preceding loading procedure is repeated for the second and subsequent rounds.

Dick Landgraff's notes to above

It should be noted that the rammer-operating handle has three positions of ramming speed employing a series of dump valves.  With the handle all the way forward, the fastest and most powerful ramming speed is obtained.  This is the position (speed) used to ram the projectile into the gun bore, engaging the rotating band with the rifling.  The other two, slower, speeds are used for powder bag ramming.

The above procedure describes a method of loading all six powder bags onto the spanning tray before ramming.  However, turret crewmen I have talked to (and videos I have seen) said that with the full service bags of 110 pounds apiece they are exerting quite a bit of effort to separate two forward and one aft.  Additionally, they are required to place a sheet of lead foil between the first and second bag for decoppering.  Therefore the standard procedure has been to separate only the first bag forward enough to place the lead foil behind it and SLOWLY ram the first three bags into the chamber.  Then the next three bags are dumped and SLOWLY rammed into the chamber.  The gun captain leans over the spanning tray to monitor this final ramming so as to signal the rammer operator when to stop as they want the last bag set so it is as close as possible to the mushroom head when the breech is closed.  When using reduced numbers of bags and/or reduced service bags (only 55 lbs. each) this step is a little tricky.  The reduced service bags are smaller in diameter as well as shorter.  If they are pushed too far into the breech, elevating the gun barrel will cause the bags to flop back against the mushroom head.  Often this will result in the red patch of black powder igniter to slump out of position where the primer charge cannot get to it.  This happened to New Jersey in 1968 and after extracting the powder bag with holes burned in CLEAR of the black powder patch (a good picture is in Paul Stilwell's book on New Jersey), Captain Snyder forbid the use of reduced service bags for the rest of deployment.