Will a 20 inch ar 15 shoot noticeably better at longer range than a 16.5?

You’re going to have to be a lot more specific about your needs/goals to expect anything close to a useful answer.

What ammo are you planning on shooting?  What distance are you wanting to shoot out to?  What do you consider “long range?”  What do you mean by “better?”

The easy answer is yes, but how much of a difference you’ll see is going to depend on answers to the above.

If you're getting in and out of vehicles, that four inches makes a big difference.

Yes it will shoot “better”, whether that extra performance is actually worth it is going to depend on the factors that the other posters mentioned. If you want “long range” in an AR-15 platform, then something like a 6 or 22 ARC or 6.5 Grendel is going to be a better option.

Everyone should have a 20" AR for slinging 77gr.  Soft shooting, longer sight radius for irons..what's not to like.  55 gr fmj cooking out of 20".  Velocity is king.

If that meets your needs, sure.  

I rarely use irons, so the sight radius argument is moot.  Even if you do, a FF handguard can get your front sight out beyond a rifle length gas FSB even with a 16” barrel.  If I need to shoot farther than my 77gr TMK load allows out of my shorter barreled gun, I’m grabbing my 6mm ARC.  55gr FMJ is training fodder for short range blasting.  It’s longer range capabilities (specifically wind performance) aren’t very good even out of 20” guns and at shorter range, it’s easily eclipsed in terminal performance by better projectiles/loads, even out of shorter barrels.

If it was as simple as “velocity is king,” professional end users would be using them.  As it sits, basically no one does.  

I say all this as a guy with a 20” A1 clone.  If I’m actually caring about real world performance, it’s probably the last gun I’d choose.

If you have never shot a 20” do so asap.

The 20” is worth having. It shoots incredibly soft. It turns M193 into an armor vibe checker. Everyone should have at least one rifle gas length AR in their collection. It is an experience.

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Why yes - yes it is.  If you would like to shoot 600 yards - and by the way, the distances for formal competition prone with an AR15 slow fire, is 600 yards, you damned well better be running a 20" if you'd like to do that and actually do it well.

Also, would you like to have high impact energy out farther?  Because the distance to 800 ft-lb impact energy with a 20" AR15, is considerably longer percentage wise, than it is with a 16.5" barrel as well.

You know who made a really light rifle that weighs less than most 16", but has a 20" Barrel and so hits a lot harder and goes farther?  Eugine Stoner's original M16 rifle - is who.   Way lighter and handier than most "modernized" M4's, in fact.

There are a couple of reasons for 20” guns but it really boils down to hunting, competition and the only real tactical use I can think of, hand outs.

I started my wife out on a 20”. She was very afraid of the recoil. The rifle length 20” guns have almost no real recoil. I think for a lot of new shooters and recoil systems I’ve shooters, the 20” AR is a very good starting point. You also don’t get a lot of gas in your face either. Over all the experience with the 20” guns is just more pleasant and welcoming. As for accuracy or range, I don’t think there is that much more of a difference over a carbine to matter. The carbine is great to carry around and clear buildings with, get in and out of vehicles with, but the 20” is much nicer to actually shoot. That said we did learn how to clear buildings with a OTV and the M16A2. It isn’t as easy but it can be done.

I have a 16" carbine that was built with a WOA SDM barrel. It's all tricked out with a FF rail and a HSNM trigger. I built it for my kid to start shooting service rifle.

Accuracy wise, it's probably a wash. It's harder to shoot on the COF because it's so light though. I shot it at a fair number of matches just for shits & giggles and it shot ok at 600 yards.

Just in terms of shooting pleasure, absolutely.

I think the recoil difference isn’t so great as we think it is because the noise difference is larger than we think it is. 20” guns are a lot quieter and that explosion is so much farther from your face.

And that’s why I say hand outs. I don’t want those guys clearing anything. More of a mag dump where the guy with thermal is putting tracers type of operation.

Echoing what everyone else is saying: 18-20" rifle gas is just a pleasure to shoot. Not gonna complain about the enhanced practical range and terminal effectiveness either.

Yep. Stoner had it right the first time. With a light JP bolt, restricted gas block and BCM birdcage brake my A1ish rifle shoots like an airsoft.

TFO front post and tritium rear make it fast, night capable and weigh barely over six pounds.

My 5.56 precision AR has a 16" barrel.

That outta the way, I built a 20" A1-profile barrel with a front sight base, a Midwest Ind. free float rail, ACE stock, and a Vortex Strikefire red dot. Very well-balanced, light, and damned gentle. Having the extra sight radius is great for iron sights, and 55 grain bullets are haulin' ass out of it.

It’s a vibe.

Everyone should have at least one 20” AR.

Yep.

Terminal ballistics in 5.56 is improved by the longer barrel. The small 5.56 bullet depends greatly upon velocity for effect. It needs all the help it can get. Just built a 20” AR for longer distances. It fills a 200 yds to 600 yds niche for me. Also have a 11.5”, 14.5”, and 16”s for closer stuff. But for anything at distance I need terminal effects on, I would pick the 20”. The standard 16” length isn’t bad for all around distances though.

Nice sticks. I see we have similar tastes.

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One thing that hasn’t really been discussed is that you can use an A5 buffer tube and use a collapsible stock with the 20” AR which does help a lot when it comes to maneuvering in tight spaces. I really wish the Marines kept going with their M16A5 program, the A5 buffer tube was a very useful feature. I wasn’t so sure about the monolithic upper with a fixed FSB though, I think it would have been better with a low profile gas block. The whole A5 concept still interests me. A monolithic 20” rifle with a collapsible stock would be a neat build.
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As a fan of fixed FSBs I've never been a fan of low profile gas blocks. I've always felt that once they fully committed to the flat top upper receivers as standard that they should have went with a folding barrel mounted FSB like the A.R.M.S. #41 B-L-P.

I did that on one of mine as sort of an M16A4 (the way it should have been) "clone". If I can ever manage to get a good picture of it I'd post it.

Yes, the extra barrel length is worth it for shooting longer distances.

I've got a 2012 vintage Remington R-15 VTR .223 Rem rifle with 21 in. barrel, free floating aluminum handguard; and I've equipped it with an aftermarket hydraulic buffer for additional recoil damping.  And FWIW, I also have a Remington Model 700 VTR .223 Rem rifle with 22 in. barrel

MHO, YMMV, etc.

So true. I’ve seen a couple that were ground off to clear a rail. Was tempted to do that myself. Too unartistic so I used a hammer and punch semi properly.

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Does an 18" pencil barrel with a thread protector give up anything meaningful over a 16" barrel with a flash hider?

Can you please tell me more about your T65 build?  What lower and barrel did you use?  How was the build process in general?  Looks like you went with a full refurb on the furniture and everything. Did you just have the furniture cleaned and painted?  Small parts refinished?  It’s very nice looking!

Thanks, I got lucky though and bought it already finished. The lower is a Brownells retro lower and the barrel is the same, a Brownells A1 1/12 twist barrel. I included it in this thread because it is sort of an AR and it’s a 20”. It is an interesting rifle. The sights are pretty neat.

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Thanks for the details and extra pics that thing is really good looking!  I need to at least get a parts kit and barrel stashed away but that’s exactly how I’d like to do it a total refurbish. Although some of the battlefield pickup ones do look neat.

That parts kits have shot up in price. $1,200 for just the parts. Again I got really lucky, I paid $900 for it already built. He told me he had the upper cerakoted to match the Brownells A1 lower better. The only part that isn’t correct really is that chrome colored screw that holds the handguard in place. Seems that part is missing and or broken in a lot of kits. It is a very cool rifle though, even as a piston it shoots really smooth.

https://hkparts.net/all-parts/taiwanese-t65-retro-parts-kit/

Really depends on what you want/need and what you are trying to accomplish.

You say having "over"...as you are only going to have one AR?  Then hell no.
Picking one up for poops and giggles to have with your 16"?  Sure, it is your money.

I hated my 10.5" 5.56 after one indoor range session, it pushed my to 12.5" 5.56 and 300blk.   The only upper I've taken out and fired less is my 20".   I'm going to defy the group and say everyone does NOT need a 20" AR, but if you WANT one, go for it.

Hangfire

A 20” Ar with m4 stock all the way collapsed is shorter than an akm or 16 inch rifle with stock extended. They are not ungodly long and once soon a time were considered compact lightweight carbines.

The Canadian C7. I'm looking to upgrade to a 20" barrel with the collapsing stock from my 16.5". I like this setup.

I agree with most other posters. either way has trade offs. 20" shoots much smoother and recoil is quite mellow. 16" is much lighter and easier to handle especially in tight quarters. If possible get both and see the difference yourself.

ETA; You can have both for less by getting two uppers and swapping out the lower when needed.

It’d be an inch and a quarter longer and have significantly more flash to go with its ~50fps velocity improvement. It’s up to you to decide if any of those 3 things are noticeable. I know which one stands out to me.

To the OP, yeah, 20” guns are cool, for the reasons already listed. Especially the ones that came with triangle handguards. Under 16”, increasingly narrow tolerance for range estimation errors are a significant factor in comparing barrel lengths, but not so much if we’re just looking at 16” and 20”. The extra ~100fps can make BDCs work better, though. They tend to reward velocity.

As noted above the original M16/M16A1 design was very well executed on terms of weight, handling and ballistic efficiency.

I was biased against anything other than the Garand and M14 by my preceding generation of father and uncles, but when issued an M16A1 just before the switch to the A2, I found it to be a very good combat rifle in terms of accuracy and handling qualities.  It was also reliable, if kept clean.

Years later when the Department surplussed its Colt SP1 and M16A1 uppers in preference of the shorter M4 upper (which did make for a better patrol rifle), I bought one of each of the barreled upper receivers and put them on NDS lowers.  Both are 1.5 MOA accurate with good quality 55 gr FMJ ammunition.



I was not impressed by the M16A2.  The 1” longer stock was a move in the wrong direction with everyone using body armor, and the round handguards and heavier profile forward of the handguards added some strength for use with a bayonet, but that was already long passed it tactical relevance.  The A2 adjustable sight is fine on a 500 yard known distance range, but quite frankly the original A1 sight with a small short and long range apertures was an ideal combat sight, allowing hits on torso sized targets out to 300m on the short range sight and to 350m on the long range sight, sufficient for virtually all infantry combat.

The net effect of the changes on the A2 was to make it longer, fatter and heavier, all of which degraded its handling.

The M4 didn’t help.  The short barrel seriously compromised both external ballistics and terminal ballistic efficiency. Worse any potential gain in terms of making it lighter and shorter were compromised by hanging crap on it, crap that just isn’t needed most of the time

The adoption of the 62 gr M855 ball round was also a retro grade step. With M193 and a 20” barrel you could depend on fragmentation effects out to about 200m.  With M855 and a 20” barrel fragmentation range dropped to about 140m, and in the 14.5” M4 it plummeted to about 50m, fine for CQB but poor for general infantry use.

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I did use a light weight 16” pencil weight AR for some tactical rifle matches were ranges were short and speed of handling was at a premium.  I have used it from time to time as a survival rifle where compact take down capability and light weight for aircraft use is a big consideration. With a slick side upper, pencil weight barrel, and triangular carbine length handguards it’s about as light as you can get without going to a polymer lower.  It’s 5.6 pounds with empty magazine and sling.

I really like the balance of a 20" government profile when shooting off hand.  Also:  GET BOTH!  Windham with MBT and match sights that grew from A2 receiver in my junk bin that I couldn't even give away:

Gotta love a little "Advanced Retro".  A 1976 SP1 into an A2 Receiver and C7 Upper.  One of my absolute favorite guns.

Yes
Middle of table. Favorite rifle I own.

Yes.

you mean is a 16 worth it over a 20. . a 20" turns 193 into Armor piercing

ARFCOM  answer get both.