Optimum barrel length for 308 ?

aorams

Senior Member
Joined
Sep 7, 2013
Messages
109
My 20” 308 shoots factory 165 grain Accubond loads at barely over 2500fps. 150 grain factory Accubond loads at 2700. 150 grain Accubond hand load with 47grains (Mac load) of Varget gets me 2776.
 

Marbles

Senior Member
Joined
May 16, 2020
Messages
1,055
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AK
Optimal for what? I like short barrels as I'm more concerned about the shot from 10 yards than 500. I have a 16.5 inch 308 and would not want more that 19 inches.

I’m not going to touch that one.

"This is my rifle, this is my gun. This one's for shooting,...." Not too much to touch, different story if he had said gun. 🙃
 

Sgtusmc14

Member
Joined
Mar 27, 2020
Messages
89
My 18.5” bartlein seems to go transonic at 900 with 168s. My 22” is good to 1000-1100 with 175. Perfect 308 is 20” 1-10 IMO
 

smithjd

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Joined
Oct 22, 2019
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Location
NW WI
The late Charlie Milazzo recommended 20.5” for 308 as “optimal”. I remember watching a video where Clint Smith of Thunder Ranch fame had a 21” 308 bolt as it was his “optimal”.

Without putting words in their mouths, I’d agree and define “optimal” in these cases as barrel length to get most of the powder burn (inside the barrel) without diminishing returns and degradation of handling qualities...

If you are focused on 800+ yard shots, I’d go with a different caliber, not increased barrel lengths.

FWIW, I’ve taken my 20” Tikka CTR past 1000, but it went transonic with 178 Amax somewhere after 900. Still hit a few steels on the KYL rack at 1040.
 

codyadams

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Joined
May 3, 2021
Messages
16
It depends on what you want out of it. If you want a compact rig, a .308 is not a bad option, however it is not an exception to increased velocity from extra barrel length. I have loaded 215 Bergers in a 20" .308, and was able to get 2500ish max, and out of a 24" got about 2575 max, final load was 2520, both using RL17. I have talked to people that throated the .308 out for the 215 (about 3.100"+ OAL) and ran them in 28-30" barrels and were hitting good nodes at 2675-2725 with good brass life. Velocity gain with extra barrel length will also vary depending on the powder you use.

If you want all out top performance, a 28" and proper throating for your bullet of choice will get you in the neighborhood. If you want really handy, a 16-20" is nice. If you want a middle ground, a 24 isn't bad. It is all subjective to what you want/expect from it and your uses for the rifle.
 

Sgtusmc14

Member
Joined
Mar 27, 2020
Messages
89
The late Charlie Milazzo recommended 20.5” for 308 as “optimal”. I remember watching a video where Clint Smith of Thunder Ranch fame had a 21” 308 bolt as it was his “optimal”.

Without putting words in their mouths, I’d agree and define “optimal” in these cases as barrel length to get most of the powder burn (inside the barrel) without diminishing returns and degradation of handling qualities...

If you are focused on 800+ yard shots, I’d go with a different caliber, not increased barrel lengths.

FWIW, I’ve taken my 20” Tikka CTR past 1000, but it went transonic with 178 Amax somewhere after 900. Still hit a few steels on the KYL rack at 1040.
Clint smith is a Boomer idiot.
case in point 439F21D5-47BB-40DD-B1B0-FCDB74B7B4F1.png
 

Nomosendero

Junior Member
Joined
Apr 21, 2021
Messages
14
The late Charlie Milazzo recommended 20.5” for 308 as “optimal”. I remember watching a video where Clint Smith of Thunder Ranch fame had a 21” 308 bolt as it was his “optimal”.

Without putting words in their mouths, I’d agree and define “optimal” in these cases as barrel length to get most of the powder burn (inside the barrel) without diminishing returns and degradation of handling qualities...

If you are focused on 800+ yard shots, I’d go with a different caliber, not increased barrel lengths.

FWIW, I’ve taken my 20” Tikka CTR past 1000, but it went transonic with 178 Amax somewhere after 900. Still hit a few steels on the KYL rack at 1040.
Yes, I agree for hunting Big Game it would be better to use a different round after 800 yds., 300WM for me for Elk .
I have a 308 5R Milspec 24" that is amazing for a factory rifle and I really like it at the range or out of a Blind where I may have 500 yd. shot on Deer or Hogs. I also have a RAR that I cut to 18.5" that is great in the woods, ladder stands and places where I know I won't be shooting over 400 yds. So, they fill my needs but if I had one that would do well for all, I would go 20" maybe 21".
 

Hostile1

Senior Member
Joined
Jan 15, 2021
Messages
114
Our military uses 18" barrels on ar10 platforms and they expect men to hit targets at 600m. It's all about how much powder your trying to burn. If 90% burns in a 18" tube then a 22% might get you to 95%. Do you want speed(animals don't care) or o easy to carry and shoot rifle?
 
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