XR4ever wrote:Q.:Will it be a problem if a gap is less than 4"? I thought that it is the only problem if the gap exceeds ... Subsequently, would the problem with bags position occur with raising the gun or when depressed? Would it have occur with 6 bags of full charge?
Less than 4" is OK. You obsess over this several times in your post. The spec (which you highlighted yourself) is "not greater than 4 inches". Less than 4" is FINE.
2. As far as I know a full charge was performed with two strokes of rammer loading 3 bags with each.
This is incorrect. The bags were delivered to the loading tray in groups of 3, but the first bags were pushed (by hand) towards the breech to get them out of the way of the 2nd group, not to position them. Once the 2nd group was on the tray, the rammer was then used (once) to push the 6 bags into position inside the breech.
Here is a 16" gun training film: https://www.youtube.com/watch?v=0OmOQs0ziSU
Projectile loading is at 6:00 minutes. Powder loading is at 6:30. Note that there is a skip in the film at 6:55 where the section on priming is missing.
When loading reduced charge, if I am correct, first two bags gun captain pushed by hand one by one and the last 3 were rammer operated...
Incorrect. see above. Note that whether loading six bags or just one, the ram is stopped in the same place: <
4" from the mushroom.
Q.: It seems now gun captain has to worry about last bag positioning no more than 4" away from the mushroom plate...
There are several things to note in the training film: The ramming is done at low speed. The Ram Operator has an excellent view of the loading tray and breech. The Gun Captain has an up-close view of the position, and is on the other side of the tray so he doesn't block the Ram Operator's view. Under these conditions, and with training, the gun crew should get the powder correctly positioned within the 4" spec every time.
That said, I find it interesting that - apparently - the only
control of the speed of the rammer is the position of the operator's lever. This calls for skill and good training on the part of the operator. Iirc, when Sandia Labs replicated the Iowa explosion, ramming the bags too fast was one of the factors in the accidental ignition.
I am hypothesizing here, but if the Iowa gun crew did load the reduced charge with a double-ram procedure to place the first bag near or against the shell (they violated a large number of administrative, procedural and safety protocols - the result was less accidental than it was inevitable
), then neither the Gun Captain nor the Ram Operator would have had any way of clearly gauging the position of the bags way up in the dark chamber. All it took was ramming a little too hard, a little too far to generate enough heat...
And what happens if the gun is depressed?
Based on personal experience, I recommend Prozac and gaming with friends around a tabletop.
Seriously, I don't think the guns can depress far enough for the bags to overcome friction in the barrel and slide forward.
I hope this helps.
Just because it's stupid, futile and doomed to failure, that doesn't mean some officer won't try it.
-- R. Rather