Musings on 20" ARs

[Podmonkey]

For a few months now I have been day dreaming on a particular AR Build, what I would call an Outdoor Patrol Rifle. I have been musing on what role the traditional 20" rifle length AR m8ght still have these days and my theory is that if we rule out vehicle and indoor scenarios the 20" becomes optimal. I imagine an AR with some effort and expense towards keeping things as l8ght and simple as possible, such as with lightweight receiver sets and lighter barrel profiles, could benefit from the extra velocity and therfore range of a 20" setup. I specifically envision a build based around something like the 2A Armaments Balios lightweight receiver set, a medium-light taper barrel or even a pencil barrel, a lightweight fixed stock like a magpul MOE Rifle stock and a carbon fiber handguard (I like Smoke Compsites' stuff) would give us a quite capable yet reasonably light setup for open country work, could ale9 s4ve as wn ersatz DMR . I think I'd pair it with a good prism sco0e f9re simplicity and low weight.

 

[dsdmmat]

I prefer a 20” barreled rifle. If being used as a patrol rifle I would keep it to a govt profile vs the pencil barrel.

How to Choose the Right AR-15 Barrel Profile | Ballistic Advantage Blog

AR-15s are so versatile that you can use them for combat, home defense, hunting, plinking, and more. However, how good the gun will be for your desired purpose will depend on its...

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[Zerex]

Hornaday CX bullets will be the proper load.................70 g about duplicates the old FBI barrier blind standard.........

I recommend an 18" Mod 12

 

[turbobike]

I prefer the 20" barrel...almost zero percieved recoil (longer recoil impulse), maximum FPS from ammo, ...

 

[Jcp123]

Sure, if it’s that specialized. I wouldn’t do it for a “one and done” rifle, but if it’s one for a specific purpose, why the hell not?

 

[dwa12479]

My stable only includes one 20 incher. But it's one of my faves for exactly what you described. Its not HD or CQB, but more for a SHTF scenario. Luth AR stock. FORTIS free float handguard. Bushnell 4-12x 50mm scope with 45 deg offset backup irons just in case. Built for under $1k

 

[FP1201]

The Military adopted the 20" barrel for damn good reasons, it was the "house to house" and vehicle born fighting that lead to the need and development of shorter barrels and stocks...personally for my "Go To" is a 20" A1 (Retro Rifle) with a Chrome bolt/carrier and chrome lined bore.

 

[Podmonkey]

Mostly I have been thinking about what a fully modernized, non retro, full sized AR15 would look like and what it would be good for.
My thoughts thus far are that such a rifle would be optimized for outdoor use over open country. As always I think keeping the weight down as much as practical is key, you don't want to be stomping around 9ver significant distances with something heavy strapped to you, hence a lighter weight barrel profile and spending the extra money on lightweight components.
I think a big advantage of the 20" barrel is to extend the useful range of cheap M193 loads which are very effective within their fragmentation range. And when mostly on foot I don't think a 20" AR is all that cumbersome.

 

[Vapor]

I'm not a military. I don't plan on cqb. I'll just burn the castle down if you know what I mean. I'll take a 20" all day

Mine has a 1-4x, yhm barrel, and larue trigger.

The only gun I like more is my 18" ar10.

 

[Xae289]

That sounds like a really fun setup

 

[dsdmmat]

I make/ build guns mainly for something to do. I like to do things with them most people or companies won’t. Like mate a 3.5” 9mm slide to a full sized double stack frame giving me 18 rounds of ammo in a short barreled package.

With the large and small framed ARs it is no different. I have done everything from 7.5” - 24” barrels. I usually go heavy or heavy fluted just because I have no delusions of running patrols or bugging out with a 35 pound ruck on my back, 65 pounds body armor, 24 spare mags, M17 with 10 spare mags on my hip and a ballistic helmet on my head. Those days are long behind me. Now I am more likely to be the guy locking down an intersection or overwatch to the patrols.

I have played around with lighter profile barrels and minimalist handguards and stocks. If I was to take something out on patrol it would most likely be one of my civilian copies of the iron sighted M16A2.
good to 300 meters, heavy enough to not wander if I need to put a lot of lead down range in a short period of time, and finally I am very comfortable with that package.

I like your thoughts on the platform’s design @Podmonkey, for what you want to do, it should serve you well.

I would caution you against the skeletonized receiver designs on the market. Too many places for foreign objects to introduce themselves and gum up the works.

You may want to look at titanium receivers(Titanium AR-15 Receiver By Amalgamated Ti), carbon fiber wrapped barrel, skeletonized bolt carriers, and a flat wire buffer spring. Those combine with a carbon fiber handguard will give you a good base for the build. There are some good polymer offerings out there these days which could also be considered.

 

[Podmonkey]

I make/ build guns mainly for something to do. I like to do things with them most people or companies won’t. Like mate a 3.5” 9mm slide to a full sized double stack frame giving me 18 rounds of ammo in a short barreled package.

With the large and small framed ARs it is no different. I have done everything from 7.5” - 24” barrels. I usually go heavy or heavy fluted just because I have no delusions of running patrols or bugging out with a 35 pound ruck on my back, 65 pounds body armor, 24 spare mags, M17 with 10 spare mags on my hip and a ballistic helmet on my head. Those days are long behind me. Now I am more likely to be the guy locking down an intersection or overwatch to the patrols.

I have played around with lighter profile barrels and minimalist handguards and stocks. If I was to take something out on patrol it would most likely be one of my civilian copies of the iron sighted M16A2.
good to 300 meters, heavy enough to not wander if I need to put a lot of lead down range in a short period of time, and finally I am very comfortable with that package.

I like your thoughts on the platform’s design @Podmonkey, for what you want to do, it should serve you well.

I would caution you against the skeletonized receiver designs on the market. Too many places for foreign objects to introduce themselves and gum up the works.

You may want to look at titanium receivers(Titanium AR-15 Receiver By Amalgamated Ti), carbon fiber wrapped barrel, skeletonized bolt carriers, and a flat wire buffer spring. Those combine with a carbon fiber handguard will give you a good base for the build. There are some good polymer offerings out there these days which could also be considered.

Receiver sets such as the Balios are not skeletonized. Such receivers often have extensive milling to remove as much material as practical while remaining "whole" I guess you could say or they may use exotic lightweight alloys to reduce weight. In either case however the cost is high.
Here is the 2A Armament product:

2A Armament Balios Lite Receiver Set - Gen 2

The lightest billet receiver set on the market, this Gen 2 receiver has a flare magwell, weighs just 12 ounces and ships absolutely FREE. Shop today and save.

www.righttobear.com

As you can see it is an extremely expensive machined billet set but is substantially lighter than typical.
They also offer a forged version that is likewise machined to reduce weight. It is about half the cost and only very slightly heavier. There are other manufacturers with similar receivers, the general idea here is to gain back some weight savings that the 20" barrel otherwise incurres, the sacrifice being to the pocket book.
I think keeping the weight down on an AR is important as thar is one of the designs unique traits: simplicity and handiness.
On that note, modern manufacturing has allowed pencil profile barrels to avoid the worst drawback- that of POI shifts as the barrel heats. Modern pencil barrels will keep the group centered at the point regardless of heat, the groups will open up significantly of course but the trade off is to provide something that both optimizes velocity while still being easy to carry. My concept is that of a rifle that is carried more than it is shot.

 

[Podmonkey]

On a side note I spec a 5.56 chambering simply because that is the common and cost effective option. However given this would be a lower volume shooter perhaps a more expensive and more suitable caliber is called for? The .224 Valkyrie would be a good fit but I have heard that cartridge is just a about dead, which I find unfortunate.
Since we are daydreaming I propose my own fictional cartridge- basically the 6.8 SPC case necked down to 6mm instead of the Valkyrie's .22, and optimized for heavy for caliber bullets.
There is the 6mm ARC but that is based on tge 6.5 Grendal case which means proprietary bolts with sub optimal bolt face dimensions and wonky, proprietary magazines. Two issues which a 6.8 based cartridge avoids. I'm dumbfounded such a cartridge hasn't already been released to market.

 

[Drinkthekoolaid]

I keep thinking it would be super fun to have a modernized m16a4-ar15 hybrid setup in 20" length.

 

[dsdmmat]

On a side note I spec a 5.56 chambering simply because that is the common and cost effective option. However given this would be a lower volume shooter perhaps a more expensive and more suitable caliber is called for? The .224 Valkyrie would be a good fit but I have heard that cartridge is just a about dead, which I find unfortunate.
Since we are daydreaming I propose my own fictional cartridge- basically the 6.8 SPC case necked down to 6mm instead of the Valkyrie's .22, and optimized for heavy for caliber bullets.
There is the 6mm ARC but that is based on tge 6.5 Grendal case which means proprietary bolts with sub optimal bolt face dimensions and wonky, proprietary magazines. Two issues which a 6.8 based cartridge avoids. I'm dumbfounded such a cartridge hasn't already been released to market.

I have a few rifles chambered in 224 Valkyrie. Have to order the ammo on line or reload around here as I have not seen it in stores in a while. Same goes with 38 Super, 35 Remington, 17 WSM, 17Remington, and 270 WSM but all of it can still be obtained.

KAK industries has introduced a 17/556 which looks to make use of the AR platform for varmint hunting. It is an interesting round and I may end up replacing my 17 Remington upper.

 

[FP1201]

Mostly I have been thinking about what a fully modernized, non retro, full sized AR15 would look like and what it would be good for.
My thoughts thus far are that such a rifle would be optimized for outdoor use over open country. As always I think keeping the weight down as much as practical is key, you don't want to be stomping around 9ver significant distances with something heavy strapped to you, hence a lighter weight barrel profile and spending the extra money on lightweight components.
I think a big advantage of the 20" barrel is to extend the useful range of cheap M193 loads which are very effective within their fragmentation range. And when mostly on foot I don't think a 20" AR is all that cumbersome.

I remember watching Film footage from the 60's or 70's of Inuits in Alaska Hunting (and killing) Polar Bear using a M-16/AR-15 to do so...(clearly of the Colt SP or "A1" variety) and doing so effectively...I have killed Deer with a Ruger Mini-14 in the 150yd. range with one shot to the coconut or neck (ok, the second animal got a second shot to quickly end it) and I was using 55gr. Remington Cor-Lok.
Surplus "Ball" rounds that are typically FMJ Spitzer bullets also cause Hypovolemic shock rather quickly without making the meat look like the plunge of a core Drill...."Lead Free" goes through and that'll be the option for many.

 

[Podmonkey]

To be honest if I were to put together a 20" it would actually probably be a bench gun for target work. Some bull barreled lead hippo of a gun with the sole purpose of making tiny little ragged holes on paper.
To be clear this is all just another one of my thought exercises, any gun money I have in the near future will be going to fund my (hopefully) newfound .357 Magnum habit..........provided S&W returns my revolver to me in a proper working condition. NoI am not going to stop bitching about that.

 

[dsdmmat]

I do enjoy my bench guns, I did go to Academy sports and they were pretty well stocked with 224 Valkyrie. So I snagged some.

 

[Podmonkey]

I do enjoy my bench guns, I did go to Academy sports and they were pretty well stocked with 224 Valkyrie. So I snagged some.

Imagine this then: 20" target build based largely around JP Enterprises parts including receiver set and barrel and BCG, LaRue MBT trigger (for $80-$90 I see no reason not to) an extended Delta style handguard from PRI, with riser bridge, and a Magpul PRS stock. The "Bench Pig". Although given my conceit that every gun in my collection must have some theoretical field use we can say it represents the SPR that SOCOM really wanted.

 

[dsdmmat]

Imagine this then: 20" target build based largely around JP Enterprises parts including receiver set and barrel and BCG, LaRue MBT trigger (for $80-$90 I see no reason not to) an extended Delta style handguard from PRI, with riser bridge, and a Magpul PRS stock. The "Bench Pig". Although given my conceit that every gun in my collection must have some theoretical field use we can say it represents the SPR that SOCOM really wanted.

20” HB 5.56

 

[FP1201]

I do enjoy my bench guns, I did go to Academy sports and they were pretty well stocked with 224 Valkyrie. So I snagged some.

Got one just because I had several boxes of ammo....haven't even put an optic on it.

 

[Robin]

I put together an upper using a 20", .223 Wylde, not a bull barrel. It seems to like everything and pleases me with great accuracy. I haven't run it through the chrono yet, I'm interested in the difference in FPS compared to the 16" , .556 chambered barrel.
Robin

 

[Vapor]

Here's my 20". Most accurate iron sighted rifle I've ever had. Like I can shoot 1.5 inches at 100. I'm sure I'm the limitation.


PSA premium bcg, yhm 20" nitride barrel, larue trigger, cmmg lower parts kit, Troy sights, seekins hardgaurd, larue scope mount, and Burris MTAC 1-4x.


She's been since returned to her correct form since leaving NY..

 

[Vapor]

It's my favorite 5.56 rifle to be honest. I may like my 18" ar10 more


That is until I lost both in a terrible boating accident

 

[FP1201]

Mostly I have been thinking about what a fully modernized, non retro, full sized AR15 would look like and what it would be good for.
My thoughts thus far are that such a rifle would be optimized for outdoor use over open country. As always I think keeping the weight down as much as practical is key, you don't want to be stomping around 9ver significant distances with something heavy strapped to you, hence a lighter weight barrel profile and spending the extra money on lightweight components.
I think a big advantage of the 20" barrel is to extend the useful range of cheap M193 loads which are very effective within their fragmentation range. And when mostly on foot I don't think a 20" AR is all that cumbersome.

Back about 2000 when AR's were suddenly becoming popular in numbers, a Complete Upper was $500.+ and with the 62gr. Military Round everybody just had to have a fast 1:7 twist or they were told it wouldn't shoot...Someone had a Stainless, 1:14 Twist Barrel that they couldn't give away; I bought it for a dirt cheap (back then) price, and that upper would SHOOT! I had a lot of South African 5.56 Ball and I swear it would cut the same damn hole at 100yds all day long....