NOTESow Mf'Report ^ Recoil 

 o/^ Shot-gun Cartridges 



ONE often hears the question asked, why Is the noise 

 and recoil less with smokeless than with black 

 powder cartridges? At first sight it seems curious that 

 whilst the propulsive effect on the shot is the same, the 

 backward recoil of the gun, and the disturbance of the eiir 

 which causes sound, should be so much heavier in one 

 case than in the other. The phenomena of extra noise 

 and recoil are, in fact, closely related as action and re- 

 action one to the other, just as the main recoil is connected 

 w^th the velocity and weight of the projectile. 



We showed in No. 1 4 of the Journal that recoil might 

 be divided into two parts, viz., that due to the velocity 

 Imparted to the shot and wads, and that caused by the 

 escape of the gases. It is found by experiment that the 

 extra momentum due to the escape of the gases is with 

 black powder about 'hb% of the momentum of the shot. 

 In the case of bulk smokeless powder the excess is only 

 25^ ; with "extracted" powder, 20% ; and with con- 

 centrated powder, about 15%. The weights of the 

 charges are about 1 6 % , 8 % , 61 % , and 5 % respedively 

 of the weight of shot and wads. If we divide the per- 

 centage of excess recoil by the ratio of weight of powder 

 and shot, we get for black powder, \ % = 2" 1 8, for bulk 

 powder, V = 3' 1 2, for "extracted" powder, %%"= 3 '03, 

 and for concentrated powder, V = 3 00. 



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