PRINCIPLES OP GUNNERY, 
Disadvan¬ 
tages of 
windage. 
32 
But, on service, studs on the projectile are liable to be set up and to 
corrode; also the gun becomes foul from continued firing; so that a 
certain fixed amount of windage is absolutely necessary, both over the 
body and over the studs. The dimensions of the hollow cylinder gauge 
and the solid plug’ gauge are adjusted accordingly, so as to ensure the 
requisite amount of windage being given which has been found prac¬ 
tically necessary for the ordinary conditions of service. 
There are certain disadvantages in having windage which it has 
been the object of artillerists to nullify, or mitigate as much as possible. 
They are :— 
(1) Loss of powder gas, which escapes by the windage without 
increasing the velocity of the projectile. 
(2) The scoring, or guttering effect which this rush of gas has on 
the bore of the gun, after a few rounds are fired. In the larger nature 
of guns, this scoring becomes of serious importance : the upper portion 
of the bore—where the rush is greatest—becoming excessively scored, 
rendering the gun unserviceable. 
(3) The compression of the studs upon which the weight of the 
projectile rests when rammed home, owing to the great pressure caused 
by the rush of gas over the projectile at the first instant of discharge. 
In some cases, the lower studs— i.e., the studs which bear the weight of 
the projectile—become so compressed that the clearance is abolished, 
and the body of the projectile comes into.contact with the grooves of 
the gun; thus tending to strain inordinately both the projectile and 
the gun. When this has been the case, an examination of the re¬ 
covered projectile usually shows the marks of the groove of the gun on 
its body. 
(4) The liability to non-centring, and so diminishing the range and 
accuracy of the gun. 
These disadvantages have to a great extent been obviated in the 
larger nature of guns by the employment of a copper gas-check at the 
base of the projectile, which is expanded into the grooves of the gun, 
&c., by the shock of discharge; so that the projectile is centred and 
the windage sealed. 
Windage is useful in the M.L. guns, as it allows the rush of heated 
gas over the projectile at the moment of explosion to ignite the quick- 
match in the time fuze, and to set it in action; but with reduced 
charges, such as are used in indirect or curved fire , the heat developed 
is not sufficient to ensure the ignition of the quickmatch. The fuze in 
such cases is wrapped round with a strand of gun-cotton, to make 
ignition certain.* 
On the other hand, with percussion fuzes having safety-pins (such 
as the Royal Laboratory percussion fuze), which are withdrawn when 
the fuze is fixed in the shell, some arrangement must be made to 
prevent the heated gas penetrating through the hole thus made^ and so 
causing premature explosion. 
* See “ Treatise on Ammunition,” p. IBs" 
