SG barrel length to ensure all powder is burned up?

[CanuckShooter]

Does anyone have any numbers on what barrel length you need to ensure all of the powder is burned up in a 2.75" shell to ensure maximum velocity?

Thanks!

 

[Wildfoot]

there are a few threads on cgn already about this. I will try and dig them up for you.

The drop in preformance is minimal when dropping down to a short barrel like a 14" or 12". But I cannot remember the optimal length to obtain the most preformance from a 2 3/4.

 

[darkshadow]

12.5" iirc

 

[SCDL]

~13 inches is all you need.

 

[Win/64]

15" is prefered.

 

[870P]

The powder may be burned up relatively quickly {no more than 17 inches tops IIRC} but it also needs time to impart its energy to the projectile, and that means means at least 24" of barrel.

 

[ben hunchak]

Some people may get mixed up with velocity and the ability to hit/point, the longer barrels won't show much more velocity in my experience, but will be much easier to hit with(swing/barrel dynamics).

 

[Wildfoot]

The powder may be burned up relatively quickly {no more than 17 inches tops IIRC} but it also needs time to impart its energy to the projectile, and that means means at least 24" of barrel.

after all the powder is burnt you are losing energy to friction. The shot will be slowing down (losing energy) as soon as the powder is all burnt. kE is 1/2m*v^2 so the energy is determined by the shot speed. a 12" barrel will shoot shot slightly slower than a 18 or 20" barrel, but going to a longer than 18" tube will not empart more energy into the shot. Longer tubes are only good for the balance, swing and sight distance on a shotgun.

 

[Win/64]

Longer tubes are only good for the balance, swing and sight distance on a shotgun.

Probably the most important thing.

 

[darkshadow]

The drop in preformance is minimal when dropping down to a short barrel like a 14" or 12". .

12.5" iirc

~13 inches is all you need.

15" is prefered.

no more than 17 inches tops......at least 24" of barrel.

a 12" barrel will shoot shot slightly slower than a 18 or 20" barrel,

And the winner is?????


I remember a thread, talking about an article. Where some guys took a long barrel shotgun, a chronograph and a saw.

Took a shot, then cut an inch, take a shot, cut and inch etc. And the top velocity was IIRC 12". Can any one find something conclusive?

 

[870P]

after all the powder is burnt you are losing energy to friction. The shot will be slowing down (losing energy) as soon as the powder is all burnt. kE is 1/2m*v^2 so the energy is determined by the shot speed. a 12" barrel will shoot shot slightly slower than a 18 or 20" barrel, but going to a longer than 18" tube will not empart more energy into the shot. Longer tubes are only good for the balance, swing and sight distance on a shotgun.

After the powder burns it's still going to make for a couple of inches worth of useful gas pressure within the barrel. Almost every chronograph results summary using the same barrel I've seen shows a reasonable velocity increase beyond the distances where the powder is burnt up.

 

[Juster]

Burning all the powder and maximum velocity aren't the same thing.

Before all the powder is burnt you are losing energy to friction too.