18" vs 20" AR

shocker998md · Sep 16, 2013

Looking for input here. Looking at shooting 100-600 yards and be able to hit a paper plates at that distance. 18" noveske or 20" barrel. I can hand load 223 and will want to plink 55 grains but have some good heavy rounds at about 69 grains for when I'm going the distance.

I've ruled out the 24" barrel, its not worth it in my opinion but is the two inches less in barrel length worth the weight savings vs the 20?

This will be built with good parts and good optics but I'm not sure which barrel to buy.

Chris05STi · Sep 16, 2013

Interested as well!!

ride4frnt · Sep 16, 2013

IMO a 20" barrel is too much. An 18" SPR barrel will get you there. noveske, rainier, white oak, dpms and plenty others all make 18" spr profile barrels. Shop around, it's really in what you want for your gun.

BradMacc82 · Sep 16, 2013

Velocity difference is not worth the extra weight of the 20", IMO.

18" will more than adequately do the job if the ammo, optics, and shooter are up to the task.

As for the barrel - what's your budget? How long are you willing to wait for one (since lead times are still high for some makers)?

jr88 · Sep 16, 2013

Either would be fine, but you have a more difficult time finding a 20 anymore. Make sure you get the right twist rate though. 1/8 would be my choice if looking for happy medium that is accurate for both weights you mentioned. Brownells has a nice White Oak 1/8 mid gas 18" ss for about 270. Wilson Combat has the same barrel in their name for 249. I think PSA also carries the WC's now as well. They are both sub moa with decent factory ammo, better if you reload. You could also spend twice that much, but I can't shoot well enough to see the difference.

shocker998md · Sep 16, 2013

BradMacc82 said:
Velocity difference is not worth the extra weight of the 20", IMO.

18" will more than adequately do the job if the ammo, optics, and shooter are up to the task.

As for the barrel - what's your budget? How long are you willing to wait for one (since lead times are still high for some makers)?

I've got time because there is no way in hell I can afford to build it and immediately put good optics on it.

I figure even though the noveske is pricy it comes with the gas tube and block installed. Best price on a 20" was 460 with a matching bolt.

I want to eventually build two rifles that are dead nuts crazy. That's why I'm wanting noveske. If I had to put a rifle to hell and back if needed. Plus with an spr I can use that to pop groundhogs with or coyetes down here in Nc.

BradMacc82 · Sep 16, 2013

If you got the money to spend, Noveske is always a good option in my experiences with their barrels. I'm a believer now.

Honestly though, if you find yourself wanting to scratch that itch before you find a Noveske set, White Oak does make a great barrel. There's a reason why their lead times are what they are.

The White Oak would dent the pocket less, and likely weigh a bit less too. But between the 2, I'd have a tough time myself. Noveske would be leaned towards simply because you get more than just the barrel.

ride4frnt · Sep 16, 2013

shocker998md said:
I've got time because there is no way in hell I can afford to build it and immediately put good optics on it.

I figure even though the noveske is pricy it comes with the gas tube and block installed. Best price on a 20" was 460 with a matching bolt.

I want to eventually build two rifles that are dead nuts crazy. That's why I'm wanting noveske. If I had to put a rifle to hell and back if needed. Plus with an spr I can use that to pop groundhogs with or coyetes down here in Nc.

Yeah, they do come installed, problem with that is they need to be removed to install the barrel nut. I have a noveske and those features are nice, but I don't think I could warrant an extra 200 bucks just because it comes with 40 dollars worth of parts.

ride4frnt · Sep 16, 2013

The other thing to look at is the chambers. Most long barrels like that come with wylde chambers, noveskes are 5.56 chamber IIRC

BradMacc82 · Sep 16, 2013

ride4frnt said:
The other thing to look at is the chambers. Most long barrels like that come with wylde chambers, noveskes are 5.56 chamber IIRC

And basically a Wylde is a blend of 5.56 and .223.

Noveske uses the Mod 0 chamber, which still allows useage of the very long and heavy match rounds. Either way, both are great options.

I couldn't say anything about durability because I don't know how long the average White Oak barrel goes before the throat opens up.

Biggfoot44 · Sep 16, 2013

( Scratches head over 20in being too long for a resonably precision rifle ) . Weight is a factor of profile and/or fluting at least as much as the 2in in question.

So pick whichever you prefer. And seems like 18in is what you have in mind.

spclopr8tr · Sep 16, 2013

So a 24 is too heavy, and there's not much difference between 18 and 20? So why not a 16 1/2? Can't be that much difference in accuracy right? But intuitively I'm thinking we've gone from a 24 down almost 8 inches, and that doesn't make a difference. How can that be?

I guess there is a trade-off between weight, length and accuracy. Like the OP, I'm still trying to figure out what the optimal trade off is for my personal requirements of weight versus accuracy.

I'm still scratching my head though over the OP ruling out the 24 over a 20 and how that equals a 2 inch difference in length.

Yoshi · Sep 16, 2013

Accuracy is not effected by barrel length. What you lose with the shorter barrels is velocity.

The difference in velocity is approx. 20-50fps per inch of barrel depending who you talk to. YMMV. So, the 16" v. 18" is somewhat, mute.

I'd go with an 18"... The happy medium.

spclopr8tr · Sep 16, 2013

Yoshi said:
Accuracy is not effected by barrel length. What you lose with the shorter barrels is velocity.

For 600yds, 16"-18" will get you there.

So a 2 inch barrel pistol is just as accurate as an 8 inch barrel? Likewise a SBR is just as accurate as a 24 inch long gun? Doesn't the length of your sight line contribute to how accurate you can aim?

501st · Sep 16, 2013

shocker998md said:
Looking for input here. Looking at shooting 100-600 yards and be able to hit a paper plates at that distance. 18" noveske or 20" barrel. I can hand load 223 and will want to plink 55 grains but have some good heavy rounds at about 69 grains for when I'm going the distance.

I've ruled out the 24" barrel, its not worth it in my opinion but is the two inches less in barrel length worth the weight savings vs the 20?

This will be built with good parts and good optics but I'm not sure which barrel to buy.

If you will be mostly shooting in the benchrest/prone position , get the 20.

Standing or moving while shooting, get the 18.

The problem with Noveske's 20 is that it is essentially a heavy barrel (not the same profile as the 18) which limits its usefulness due to the additional weight.

spclopr8tr said:
So a 2 inch barrel pistol is just as accurate as an 8 inch barrel? Likewise a SBR is just as accurate as a 24 inch long gun? Doesn't the length of your sight line contribute to how accurate you can aim?

He is talking about the inherent accuracy of the barrel, not how effective a person is at shooting with x barrel length.

Yoshi · Sep 16, 2013

spclopr8tr said:
So a 2 inch barrel pistol is just as accurate as an 8 inch barrel? Likewise a SBR is just as accurate as a 24 inch long gun? Doesn't the length of your sight line contribute to how accurate you can aim?

My assumption was that we were talking about "rifle" barrels in a "rifle" post. In any case, your sight line only matters if you are using iron sites. Of which, the alignment of the sites is a variable determined by the shooter and not the inherent accuracy of the barrel. (All things being equal that is.)

The accuracy of shorter rifle barrels can be argued to be better than the longer ones due to harmonics, vibration, blah, blah, blah... The longer barrels do have advantages, but those really aren't realized with the AR platform unless you switch to a different caliber.

I'll defer to Ed Shell for further explanation.

shocker998md · Sep 16, 2013

I just don't want to regret buying a 20 if the 18 will do. Would the volecity increase make the round be noticbly harder hitting down range?

Rifle will be lugged around and will be shot from kneeling and prone mostly but if need be will be shot from the standing 100yrds or under.

This has got my brain thinking. I want a dead reliable rifle that can survive extreme environmens not necessarily rounds touching each other on paper.

vector03 · Sep 16, 2013

The problem with the length is where it is...it's at the end of the barrel. Any additional length is at the end of the barrel. 2 inches can make a big difference when it's hung off the end of the barrel when shooting offhand.

501st · Sep 16, 2013

shocker998md said:
I just don't want to regret buying a 20 if the 18 will do. Would the volecity increase make the round be noticbly harder hitting down range?

Rifle will be lugged around and will be shot from kneeling and prone mostly but if need be will be shot from the standing 100yrds or under.

This has got my brain thinking. I want a dead reliable rifle that can survive extreme environmens not necessarily rounds touching each other on paper.

Get the 18 and don't look back.

Biggfoot44 · Sep 16, 2013

Ok. Now we have : Rarely shot offhand. Capable of being carried (slung ? ) . Extreme accuraccy not important, but reliability is.

It's not the sexy flavor of the month at the moment , but my stock Colt 20in A2 profile does MOA with irons.

But since the abstract theory was brought up , length at worst has no effect on mechanical accuraccy . Ie. 2in revolver from a machine rest would have same accuraccy potential as an 8in. Practical accuraccy ( ie from your hands ) is effected by weight , balance , trigger pull , sight radius , etc. In rifle bbls , for a given dia , a shorter bbl is theoretically MORE accurate. Stiffer , less effected by harominics. In the real world , once again weight , balance , and sometimes velocity are factors of practical accuraccy.

18" vs 20" AR

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