AR 10 308 Build 18 or 20?

[rheology1]

I’m currently building a AR 308 range rifle. I’m building it using a Wilson Combat matched upper and lower. I’m trying to decide on a super sniper 18” or 20” barrel. The rifle will only be shot suppressed. My local range goes out to 700 yards but I’d like to push it to at least 1000 although I may have to travel a bit to find another range. Since I’m not concerned about weight or hunting etc would it be beneficial to just go with the 20” barrel. It seems based on research there isn’t a huge difference between the 2 but as previously stated it will only be a range rifle. Any advice would be appreciated.

 

[wvfarrier]

I havent found much advantage between 18 and 20" in my 308s. Now 18 and 24 have a significant difference.

 

[Dogtown]

If you're limited to 700 yards and want a rifle that's handy, shorter is probably better. For comparison, I have three large frame ARs, and all are 16" barrels (two .308WIN and one 6mm Creedmoor), and all are well suited to shooting inside of 1000 yards.

 

[rheology1]

If you're limited to 700 yards and want a rifle that's handy, shorter is probably better. For comparison, I have three large frame ARs, and all are 16" barrels (two .308WIN and one 6mm Creedmoor), and all are well suited to shooting inside of 1000 yards.

I don’t see myself going past 1000 and if I starts pushing farther than that consistently I’ll probably build a different caliber rifle. If the 18 can do it I may go that direction since I’ll be adding a suppressor which will add additional length. It’s basically just a range toy I can have fun with shooting long range for reasonable ammo cost. I’m also currently building a 6 ARC on a Seekins platform so I have multiple irons in the fire at the moment. I’m looking to go 20-22” on that setup.

 

[bigjake83]

I have both 18" and 20" .308 gassers and have owned several of each in the past all with rifle length gas. Going off of absolute performance taking into consideration Barrel Harmonics and Heat Dissipation the 20" always seems to outshine the 18" even when running a heavier profile. So I would recommend getting the 20" and enjoy the added benefits and muzzle velocity.

 

[BCP]

all things being equal probably 30fps difference between 18-20 308s. I would rather have a good quality medium contour 14.5-16 barrel and just figure its not going to be a 1000 yard f class rifle

Especially with a suppressor

 

[db2000]

16 or 18 for .308.
Those few inches make a difference in length when suppressed and not really in performance inside 1000. I use 18 in .308 personally as it’s closest to 20” ballistics so why not. I have a hard time buying 2” makes any real difference in heat dissipation when suppressed but don’t have any scientific argument against it.

 

[KZP]

I went with 20" for my range toy AR-10. I want all the FPS I can get.

 

[celltech]

Unless you handload some hot rounds neither will likely keep anything supersonic much past 850 yards. Go 16-18" and enjoy it with the can...

 

[rheology1]

all things being equal probably 30fps difference between 18-20 308s. I would rather have a good quality medium contour 14.5-16 barrel and just figure its not going to be a 1000 yard f class rifle

Especially with a suppressor

Once I finish this 308 and my 6 ARC I’m building a 12.5 308 dedicated suppressed rifle (like most of my fleet) for hogs. Eventually I’d like to go thermal or nods but I’ve gotta stop the builds and save up awhile.

 

[Pappasniper]

I feel like a 20 inch AR10 is plenty handy to me for a range rifle, so I like the extra velocity albeit just a little. In the end, its personal preference.

PB

 

[Mike_in_FL]

I can't really give you the advice on the length to choose. I would only caution you that if you go with an 18 make certain it is still rifle length gas and not an intermediate as you'll be adding pressure with the suppressor.

 

[RUTGERS95]

all things being equal probably 30fps difference between 18-20 308s. I would rather have a good quality medium contour 14.5-16 barrel and just figure its not going to be a 1000 yard f class rifle

Especially with a suppressor

this

 

[rheology1]

I went with the 20”, I’ll throw my Nomad Ti on it and let her eat. I was planning to build a 12.5 308 for hogs but ordered a Scar 17s instead. I’m part way through building a 6 ARC also so regardless I’ll have some fun. lol

 

[Steve_In_29]

I went with 20" for my two. Wanted the extra FPS as I'm not shooting .308 just to generate huge fireballs. There are better caliber options for a short barreled rifle.

 

[bigjake83]

I went with the 20”, I’ll throw my Nomad Ti on it and let her eat. I was planning to build a 12.5 308 for hogs but ordered a Scar 17s instead. I’m part way through building a 6 ARC also so regardless I’ll have some fun. lol

Good choice!

 

[81STFACP]

I went from 20 to 16-1/2 to run suppressed with FA762SS. With M118 LRs 2500 was the average with LC19, LC15 were 2480. At 20 I was 2610

2480-2500, plenty good for busting CenTex WT inside 300.

20 inch, like in NRA or CMP legal service rifle with 4.5X scope will do well at 1000 yards punching paper.

 

[CaptArab]

I've had multiple 16, 18, and 20 and would only go rifle gas 16 for a suppressed rig.

 

[Paradox]

I’m currently building a AR 308 range rifle. I’m building it using a Wilson Combat matched upper and lower. I’m trying to decide on a super sniper 18” or 20” barrel. The rifle will only be shot suppressed. My local range goes out to 700 yards but I’d like to push it to at least 1000 although I may have to travel a bit to find another range. Since I’m not concerned about weight or hunting etc would it be beneficial to just go with the 20” barrel. It seems based on research there isn’t a huge difference between the 2 but as previously stated it will only be a range rifle. Any advice would be appreciated.

If its for target 20-24” and nothing but bull a med barrel is useless after 8-10 rounds, if its mobile and only. A shot or two 18 is fine