Thread: Projectile vs barrel length

Originally Posted by sneeze

Considering only velocity, the best powder burn rate is governed by the projectile and the chamber not barrel length. The "faster powder for shorter barrels" is mostly myth.
There may be other advantages in reduced muzzel pressure etc with a quicker burn rate though.

I disagree. It absolutely 100% is NO myth. The end user explosion when you pull the trigger is not the burn rate. That rate is a constant (it is a quantified number in quickload). Have a play with various combinations using that program and you'll see its no joke. If i try a huge charge of slow burning magnum powder down a short barrel with a light projectile, quickload will show you the pressure curve, and tell you that the projectile left the muzzle before the propellant had finished burning in your specified barrel length.
My old powder that matched the std barrel (2209 for a 24" barrel) would not be the best for my new 29" barrel for instance. I'm using 2213sc as it produces a safer pressure curve which can actually go higher than 2209. Choosing the projectile is the last thing I do. (But that's just me)

Originally Posted by Dead is better

I disagree. It absolutely 100% is NO myth. The end user explosion when you pull the trigger is not the burn rate. That rate is a constant (it is a quantified number in quickload). Have a play with various combinations using that program and you'll see its no joke. If i try a huge charge of slow burning magnum powder down a short barrel with a light projectile, quickload will show you the pressure curve, and tell you that the projectile left the muzzle before the propellant had finished burning in your specified barrel length.
My old powder that matched the std barrel (2209 for a 24" barrel) would not be the best for my new 29" barrel for instance. I'm using 2213sc as it produces a safer pressure curve which can actually go higher than 2209. Choosing the projectile is the last thing I do. (But that's just me)

Iv got an ok understanding of burn rate and Iv had QL for quite a few years. My reference to reduced muzzle pressure with a faster burn rate was an example of why a faster burn rate might be desirable over best velocity. Probably not that relevant .

If I understand it correctly? you are saying that 2209 will give better velocity in your 24" than barrel than 2213 because it has a higher percentage of propellant burnt?