144 
SHORT NOTES ON PROFESSIONAL SUBJECTS. 
L.Gr. 
Pebble . 
Pellet 
Spherical pellet 
Pressure by crusher 
Founds. 
Muzzle 
velocity. 
gauge at 
A* 
B.f 
at 
f.s. 
tons. 
tons. 
tons. 
charge, 601b.; density 
1-648... 
6 
1273 
49 
28 
29 
// 70 j, „ 
1-751... 
6 
1435 
22 
22 
23 
a 64 n n ■ 
f 1-696... 
3 
1377 
21* 
21 
21 
i 1-626... 
3 
1384 
24* 
23 
24 
( 64 „ a 
1-677... 
1 
1352 
20 
15* 
21 
" i 70 ■„ „ 
1-667... 
1 
1380 
22* 
26* 
28 
The Committee take this opportunity of drawing attention to the very high, 
pressures indicated at the point A by quick-burning powders, such as L.Gr. and 
R.L.G. 
These indications of violent action are probably due in a great measure to the 
conical form of the chamber. There are on record numerous instances in which 
the metal of the bore, or tube has been gradually eaten into at a point correspond¬ 
ing to the position of the A crusher, namely, the centre of the bottom of the 
bore. 
The Committee have selected the following examples of this peculiar action 
which has been attributed to the particular form of chamber in each case:— 
(1) In the trial for endurance in 1867 of the 9-inch M.L.R. guns of 12 tons, 
a hole about 3 ins. deep was eaten into the end of the steel tube of gun No. 330 
after 500 rounds. This result was attributed by the Superintendent Royal Gun 
Factories to the conical nature of the chamber. (Proceedings O.S.C., 1867, 
pp. 829-30-31-32.) 
(2) A large cavity over 2 ins. in depth was developed in the bottom of the 
wrought-iron bore of the experimental 9-inch gun No. 331, during the above trial 
of endurance, after 500 rounds. (Proceedings O.S.C., 1867, pp. 1068-69.) 
(3) In testing the endurance of a 6-5-inch smooth-bore gun (Experimental 
No. 100), with inner barrel of solid forged wrought-iron, <a large cavity was 
observed at the bottom of the bore, after 60 rounds. After 100 rounds this hole 
measured 2" x L5" and 2 , 75 // in depth, with fissures extending from its edge. 
(Proceedings O.S.C., 1862, pp. 540-41.) 
(4) During the trial in 1864 of the 7-inch M.L.E. wrought-iron guns rifled 
on different systems, three of the guns were severely injured by their steel tubes 
being eaten into at the bottom of the bore. (Proceedings O.S.C., 1864, p, 627 ; 
1865, p. 343). 
(5) During the trial in 1865 of the 7-inch M.L.E. gun No. 217, a hole of 
2 \ ins. in depth was eaten into the end of the solid steel tube, thus rendering the 
gun unserviceable. (Proceedings O.S.C., 1865, p. 636.) 
(6) Many cast-iron mortars have been rendered unserviceable by holes eaten 
in this manner into the bottom of the chamber; and numerous instances exist in 
which mortars have split and burst from this cause. 
The 10-inch Experimental Gun No, 375, is chambered in the same manner as 
the service M.L.E. 10-inch guns. 
* Axis of bore. 
f Centre of Charge. 
J Front of Charge. 
