Motion of a Spinning Projectile. 375 



is not merely a question of range, for the theory in this 

 paper shows that the muzzle velocity, as well as the shape 

 of the bullet, has its effect on the drift at a given range. 







Drift. 





Range 















in yards. 





Mark VI., 







Mark VI. 



taking 7 feet 

 at 1500 yards. 



Mark VII. 



100 



00085 



0-064 inch. 



0-0053 



200 



0-0384 



0-29 



0249 



300 



00987 



074 



00663 



400 



0-202 



1-51 



01910 



500 



0365 



2-75 



0-268 



600 



0-615 



462 



0473 



700 



0-960 



7-21 



0801 



800 



1-44 



10-8 



1-260 



900 



2-09 



15-7 



1-946 



1000 



2-92 



21-9 



2905 



1100 



3-98 



29-9 



4-16 



1200 



5-28 



39-7 



5-82 



1300 



6-89 



4-31 feet. 



7-95 



1400 



8-84 



5-54 



10-63 



1500 



11-18 



7-00 



14-00 



1600 



14-00 



8-77 



18-17 



1700 



1730 



10-83 



23-34 



1800 



21-32 



13-34 



29-67 



1900 



26-20 



16-44 



37-46 



2000 



31-57 



1976 



46-90 



2100 



3811 



23-85 



58-48 



2200 



45-78 



28-66 



72-58 



80. Drift of a Larger Shot. — When X is expressed as a 

 function of the velocity it contains I or Z x as a factor, 

 whereas Z 2 , the drift, contains I 2 or Zj 2 , and both I and l x are 

 proportional to the dimensions of similar shot. For the 

 same change of velocity, therefore, the ranges of similar 

 shot are proportional to their linear dimensions, while their 

 drifts are proportional to the squares of these dimensions. 

 For a shot similar to the Mark VI. bullet and on n times the 

 scale of the bullet, corresponding ranges will be n times as 

 great, and corresponding drifts n 2 times as great as for the 

 bullet. That is, X and Z 2 being the range and correspond- 

 ing drift of the bullet, then nX and n 2 Z 2 are the range and 

 corresponding drift of the larger shot for the same change 

 of velocity. To make this rule strictly true, the muzzle 

 velocity u should be the same in both cases, and, of 

 course, N must be the same in both cases. Thus a 3-inch 

 shot has about ten times the dimensions of the bullet, and it 

 will therefore have a hundred times the drift at ten times 



