Why shorter barrels on certain calibers.

[dennishoddy]

Everything relies on the load. A 24” barrel doesn’t make a bullet any faster if the pressure generated by the powder charge has expired in 18”. From that point on, friction may actually result in lower velocity, so an 18” barrel would be optimal in this situation.
A slower burning powder that generates pressure for 20” of that 24” barrel would be what I’d be looking for.

 

[swampratt]

I did some testing on what @dennishoddy mentioned with an 18" Savage vs a 22" Ruger both in .308

Varget and IMR4064 the 4064 showed darn near the same velocities in both barrels.
Varget showed much more difference in velocities.

Those 2 are really close to each other in the burn chart.

 

[PanhandleGlocker]

I did some testing on what @dennishoddy mentioned with an 18" Savage vs a 22" Ruger both in .308

Varget and IMR4064 the 4064 showed darn near the same velocities in both barrels.
Varget showed much more difference in velocities.

Those 2 are really close to each other in the burn chart.

Mmmm I love me some IMR4064

 

[Honey Badger]

Great information guys. Thank you. I have always wondered, and now I know.

 

[Foxfire5]

The only difference between a 16-1/2 barrel and a 18 in barrel at say 800yards in accuracy is a heaver rifle. In 6.5 Grendel with 20.5 Barrel and 16.5 barrel even more weight with same results.

 

[Jcann]

I’m sure it has less to do with long range shooting or ballistics and more to do with marketing. A portable, comfortable, easy shooting, light weight/light recoiling entry level rifle sells. The average hunter will probably send no more than 10 rounds down the barrel a year, never use a chronograph, and looks at 150 yards as their max range. They get their ammo from the local GS or WalMart and probably trust the ballistic chart on the box.

My 20” Tikka T3 CTR will never outrun my sons 24” Savage (both in .260 Rem) with the same bullet weight/powder charge and brass. I’ve safely sent 140 grain Berger Hybrids down range using 43.8grs H4350 and Rem brass at 2,887fps in his Savage. These were also the most accurate shooting reloads for his rifle. I haven’t been able to load these in a long time because I can’t find Remington brass. DO NOT ATTEMPT IT WITH LAPUA BRASS. I pushed too hard trying and ended up rebuilding a Savage bolt head.

The 6.5 CM is very much like the 260 Remington ballistically. I would be interested to hear if someone has gotten a 20” barreled 6.5 CM to launch a 140gr Berger Hybrid 2,800 fps or faster (Safely).

 

[Foxfire5]

I’m sure it has less to do with long range shooting or ballistics and more to do with marketing. A portable, comfortable, easy shooting, light weight/light recoiling entry level rifle sells. The average hunter will probably send no more than 10 rounds down the barrel a year, never use a chronograph, and looks at 150 yards as their max range. They get their ammo from the local GS or WalMart and probably trust the ballistic chart on the box.

My 20” Tikka T3 CTR will never outrun my sons 24” Savage (both in .260 Rem) with the same bullet weight/powder charge and brass. I’ve safely sent 140 grain Berger Hybrids down range using 43.8grs H4350 and Rem brass at 2,887fps in his Savage. These were also the most accurate shooting reloads for his rifle. I haven’t been able to load these in a long time because I can’t find Remington brass. DO NOT ATTEMPT IT WITH LAPUA BRASS. I pushed too hard trying and ended up rebuilding a Savage bolt head.

The 6.5 CM is very much like the 260 Remington ballistically. I would be interested to hear if someone has gotten a 20” barreled 6.5 CM to launch a 140gr Berger Hybrid 2,800 fps or faster (Safely).

I don't reload any more because of arthritis. but the difference in rifle barrels inside with type of twist, grooves, depth of lands and from different barrel makers also can contribute to accuracy and range me thinks.

 

[Jcann]

I don't reload any more because of arthritis. but the difference in rifle barrels inside with type of twist, grooves, depth of lands and from different barrel makers also can contribute to accuracy and range me thinks.

You’re absolutely correct. I guess the only way to find out what happens is to take one 24” barrel, shoot X amount of rounds using a lab radar to determine muzzle velocity then cut 4” off the barrel, recrown it, and repeat the process all over again.

 

[bushmaster06]

The application of the rifle is also a consideration. Are you walking and shooting through thick woods? Are you walking from the parking lot to the bench?

When I put my .308 together I wanted something lighter and less likely to get hung up on branches and vines, all while knowing that I don’t have a need for really long shots. I ended up with a 16.5” barrel and a 1-8x scope that weighs just shy of 13# with a loaded magazine, suppressor, and bipod.

It’s the big dog on the right.

 

[HiredHand]

13#!? No, thanks. I’ll keep using my Savage 99 with a low power Leupold.