Quote
it takes more 2f to give the same speed and therefore usually the same accuracy as with 3F.
Not true. 2F will often give a higher velocity in a given gun. 3F ignites more suddenly and achieves maximum velocity closer to the breech end of the gun. thereafter, the friction of the bore might retard velocity. 2F burns more slowly and continues to accelerate the projectile further up the bore, thus achieving a higher velocity. Also, I would postulate that a faster twist barrel would retard velocity thru friction. Shotguns are notorious for achieving higher velocities with larger granulations. N'est-ce pas
Theory is great but sometimes doesn't work. We did a quickly test once with a 20 bore vs. .62 rifle. In every instance, the rifle and smoothbore either gave the same velocity or higher velocity to the rifle, I assume due to more complete or more efficient burning of the powder. Forsythe wrote that a slow twist of smooth gun gave higher velocity, which is why we did that test. His theory was proved to be incorrect in our test - with the guns & loads we used. This may have been due to out powder vs. the powders of 1850? Perhaps "back then", the smooth guns developed higher speeds. Too- we tightly patch our ball loads in the smoothbore. If they are not tightly patched, they whoooosh instead of 'crack', showing loosely patching or no patching does not improve speed.
Dave, I disagree.. Every one of my guns, from .32 to .69 give higher speeds with 3F than with the same amount of 2F. There may be a limit, ie; where the 2f charge exceeds the 3F in speed, but I have not seen it. I do realize or know that when producing the same speed as a given charge of 3F, the 2f load is producing less peak pressure - Lyman showed this in their book.
They also showed that it took more 2F to match the velocity given by 3F.
