Formula For Calculating Barrel Length????

[Owen49]

Can anyone inform me of a reliable formula for calculating the optimum barrel length for a known boolit (calibre and weight) and a known charge of black powder?

[John Boy]

can anyone inform me of a reliable formula for calculating the optimum barrel length for a known boolit (calibre and weight) and a known charge of black powder?

...why?

[Oyeboten]

You could also just adjust the Charge and or the Bullet Weight, to obtain optimum performance, for whatever Barrel lentgh the Arm happens to have.

[Doc Highwall]

Say you only want a light load using 3F powder with a light bullet and only need a 16" barrel, are you going to cut the barrel and shorten the sight radius? Just use what barrel length that feels comfortable weight wise/balance wise with usable sight radius and shoot.

[Owen49]

Can anyone inform me of a reliable formula for calculating the optimum barrel length for a known boolit (calibre and weight) and a known charge of black powder?

Perhaps I could have phrased my query in a better manner, like this:

Back when all rifle cartridges were loaded with black powder, how did the gun manufacturers determine the optimum barrel length for their known boolit (calibre and weight) and their known powder charge? Is there a formula for this calculation or was it a "hit and miss", pun intended, situation?

If one was going to build a new black powder cartridge and knew what boolit was going to be used and what powder charge was going to be used, how would one determine the optimum barrel length to get the most good from the powder charge?

[Maven]

"If one was going to build a new black powder cartridge and knew what boolit was going to be used and what powder charge was going to be used, how would one determine the optimum barrel length to get the most good from the powder charge?"

Wouldn't they have used a ballistic pendulum, targets at various distances to generate data and then calculus to come up with a formula or at least an optimum bbl. length?

[M-Tecs]

Optimum for what? Velocity is only component. Carrying and handling are another. Sight radius requirements are another. Same for lub issues. Too long and you run out of lub.

With the 22LR you can have barrels long enough that barrel friction will reduce velocity. That may be true for some of the other small volume cases but I have no first hand knowledge.

With the bigger BPCR you normally don't see rifle barrels longer that 34 mostly due to lub issues. On smoothbore muskets and some of the early muzzleloaders like the Pennsylvania rifles 44" and longer are common.

The longest I have seen is 48".