The effect of barrel weight and length is now quantifiable in terms of pounds/ounces or grams/ kilograms and moment of inertia. Note that the muzzle area of the barrels are more or less twice as far from the balance point as the butt area. Balance moves as a function weight change times length from balance point to the removed/added weight. Inertia, however, changes as a function of weight added/removed and the length form balance point squared (length times length). That is weight removed/added from butt area will have 1 weight times one length. On the other hand, one weight times two length times two length (1 W times 2 L times 2L = W times 4L) shows that a barrel weight change(such as shortening or lengthening barrels) will affect inertia by four times as much as the same weight change at the butt. So, changing the barrel length by 2" (say about 4 ounces) would have about the same effect as changing the weight at butt by 16 ounces.

From the above we can see that barrel length is a very useful tool for adjusting gun handling.

DDA