Barrel length

[bandit86]

How much would ballistics be affected if a round is fired from a rifle vs a carbine - my understanding is carbines are a shorter version of a rifle.
Also, with tupical gunpowder how fast do the gases expand in a barrel? Handgun powder?

 

[Jamie]

if you hand load you can use powders better suited to shorter barrels and really dont loose much

 

[CyaN1de]

What Jamie said.

But all things being equal you will see a 25-50fps/inch difference in velocity (slower in shorter barrel).

 

[bandit86]

So why don't they make rifles with 50 or 60 ( even longer?) inch long barrels? Sounds like a good way to make target rifles

 

[Jamie]

well in the shorter the stiffer


longer is for speed

50 or 60 might be hard to use and make

 

[AlexF]

So why don't they make rifles with 50 or 60 ( even longer?) inch long barrels? Sounds like a good way to make target rifles

Because of increased friction losses (velocity drops past a certain barrel length), expansion ratio (related to cartridge efficiency) and barrel rigidity (strongly related to accuracy).

2 very good links

• http://www.riflebarrels.com/articles/bullets_ballastics/long_barrel_velocity.htm (velocity vs barrel length)
• http://www.riflebarrels.com/articles/longrange_shooting/ideal_barrel_308_tactical_rifle.htm (barrel rigidity and deflection vs length)
• http://kwk.us/powders.html (expansion ratio is strongly related to thermodynamic efficiency)

Alex

 

[Ruthless]

If you have a caliber and powder/bullet combo I can run it on my Quickload for few lenghs

But as was already mentioned usually about 30 ft more per inch, but sure diminishing returns occur at very long barrels

Ps. On my 7mm going from my 31" to 32" would give you 10 ft and that isn't worth the weight