View Full Version : If you could design the ideal full size AR-15....
I really like the full size AR15 rifles with their 20" barrels and fixed stock...I know, I know, it is not cool these days but please indulge me. In the interest of full disclosure, my go to long gun at home is a Colt 6920; so yes, I am aware that what I like may not be the most practical...
With that said, I would like to know what you think would be the ideal full size AR15...only conditions that it must have a 20" barrel (any contour) with full length DI gas system and be chambered for 5.56x45mm...anything else is up to you...what would you do?
MadcapMagician
08-18-10, 21:26
20" SS 1/7 or 1/8 barreled upper, DD Lite Rail 14.0, bipod, Nightforce 2.5x10 in a good mount with an A1 stock.
The Dumb Gun Collector
08-18-10, 21:27
Regular old M16A1 was pretty ideal. Basically one of those or one with a flat top for RDS would be awesome.
1/8 SS barrel, ionbonded, 13" trx extreme, find out who I have to kill to get the leupold 1-8x scope, throw on a light, buis, and bipod, then continue using my 16" gun.
Belmont31R
08-18-10, 21:51
Precision in mind:
SAM-R with a good adjustable scope, SS barrel, etc.
Fighting in mind:
BCM/Colt A4 upper, ACOG/Aimpoint, etc.
I'll take a crack at this. Not all the parts are easy to come by, but since the topic said ideal, I'll include them.
Lower:
Standard A2 lower and parts
A1 grip
Colt CS stock(A1 length with A2 materials) or the new Vltor A5 stock(I'd like to handle one first)
Upper
Flat-top receiver
20" chrome lined, A1 profile barrel with a 1in7" twist
quality BCG and charging handle
A2 handguards
A2 flash suppressor
Standard FSB
DD A1.5 rear sight with a CSAT aperture
Other stuff
Aimpoint C3 in a Larue mount
Surefire G2l either bolted to the handguards or on an FSB mount
20" chrome lined, A1 profile barrel with a 1in7" twist
This, A1 handguards, and an A4 upper.
Eurodriver
08-19-10, 00:17
I'd take a BCM M16A4 clone with a Trijicon PVQ-31A ACOG.
Of course the KAC M5 rail system, with maybe a Harris bipod?
This, but with a 12" Lite rail:
http://www.545ar.com/bcms.jpg
find out who I have to kill to get the leupold 1-8x scope
My thoughts exactly. :lol:
Blankwaffe
08-19-10, 01:16
This, but with a 12" Lite rail:
http://www.545ar.com/bcms.jpg
Oh yeah Im all over that....the C7A2 type configuration is my all time favorite....but I guess Ive said that enough in previous threads already.
Give us a run down on your BCM 20" there 87GN.What buffer,action spring etc..?
Im getting prepped to add a BCM SAM-R with a A5 EMOD this fall.Hopefully...
Unfortunately your conditions kind of stiffled my thoughts. My ideal full size would have an 18" barrel, DD rail system, Battle Comp flash hider and possibly the new Vltor M5 stock. I would top it off with a Nightforce scope and a good quality bipod.
decodeddiesel
08-19-10, 09:59
Big fan of the M16A4 with the M5 RAS, M68 or TA11G ACOG (ETA: Actually, a TA33H-G would probably work a little better given the weight penalty of the TA11, but the extended range tree of the TA11 would come in handy in a mountain setting...), PEQ-15, SF M951, etc. The only thing I would change is to replace the A2 stock with a Colt CS stock as was mentioned. If I were going to A-Stan tomorrow as an 11 Bang-Bang who would be doing primarily mountain interdiction type ops, this would be my rifle of choice.
Interesting choices.....I've never heard of the CS stock...maybe I should hang out around here more often. I have heard many people say they wanted an A1 stock made from the A2 material but never thought Colt actually made it.
Unfortunately your conditions kind of stiffled my thoughts. My ideal full size would have an 18" barrel, DD rail system, Battle Comp flash hider and possibly the new Vltor M5 stock. I would top it off with a Nightforce scope and a good quality bipod.
My only conditions were 20" bbl in 5.56 and full length gas system.....I thought this wasn't too bad...in any case, without trying to derail my own thread, please explain if you will why the 18" is better than the 20"....I'm not familiar with the 18" bbls....are they anything special? Thanks
20" barrels are overrated. Yes, you get more muzzle velocity, but does nothing really for accuracy. I would venture to say that a 16" barrel will shoot just as accurate as a 20".
18" is kind of a compromise length. And it's not as musket looking as a 20".
Interesting choices.....I've never heard of the CS stock...maybe I should hang out around here more often. I have heard many people say they wanted an A1 stock made from the A2 material but never thought Colt actually made it.
My only conditions were 20" bbl in 5.56 and full length gas system.....I thought this wasn't too bad...in any case, without trying to derail my own thread, please explain if you will why the 18" is better than the 20"....I'm not familiar with the 18" bbls....are they anything special? Thanks
Ok, I see...that's what I thought it was....good to know.
as to accuracy, I figured you want a heavier barrel for that, not just longer. I did not specify what countour barrel as a condition so anything from skinny to ultra heavy is a go.
I actually like the musket looking barrel....that was my whole point in this. :cool:
If I were to go with a 20" barrel I'd go for M16A4 clone.
Regular old M16A1 was pretty ideal. Basically one of those or one with a flat top for RDS would be awesome.
With a 1/7 twist.
I like a good ole M16A4 style. Flat top with a KAC rail. Add on a Aimpoint and you're good to go.
A 1:7 twist isn't as necessary to stabilizing longer bullets in a 20" barrel as it is with a 14.5". 20" barrels attain greater velocity and the bullet will exit the muzzle at a higher RPM. It's the RPM that stabilizes the bullet, not twist rate.
There are clear advantages to the 20" barrel. One, the AR system is very reliable. Bolt velocities, operating pressures and spring rates all work in concert. The system will work with shorter barrels but it runs closer the ragged edge with a narrow margin between function and failure and require more maintenance. They are less forgiving when dirty or of ammunition changes.
As velocity is lost due to shorter barrel lengths, ammunition selection becomes more critical for terminal performance, particularly at longer ranges.
AR Carbines excel at close combat. They should, that's what they're designed for. But they are specialized and do not perform as well at longer ranges.
In choosing a good all around AR, the 20" is more versatile. Better reliability and durability, less intensive maintenance and a more forgiving configuration, it has it's appeal. Though the carbine is a better choice if I need to confront a goblin in my hallway, a 20"rifle will work.
I don't suggest that anyone should replace their AR carbines with AR rifles. But I think the 20" has lost popularity more due to fashion than utility.
The configuration I'm thinking of building is a 20" barrel with a PRI Gen III handguard. For insulation against heat, carbon fiber is better than aluminum. It'd be easiest just to use a LaRue Stealth upper. I'd like to try the VLTOR A5 stock and if that doesn't become available, the MagPul UBR. For general purpose use, an ACOG should work. For longer ranges, a good variable.
For a carbine, I think I'll start with a 14.5 pinned upper. I figure if I'm gonna go short, I'm gonna go short.
I'll tell ya though- it's sure a lot of fuss for the difference in a piece of pipe the distance between my forefinger and thumb outstretched!
I love a nice M16A4 style rifle. Hell I'm even digging the retro build stuff, so I say go for it on the 20" rifle.
Now that I have gotten that out of the way and just speaking about the .223/5.56, for practical purposes in a precision type rifle where we are more concerned about shooting over distance in a LE or Military application, I would opt for an 18" 1/7 barreled rifle over 20". I don't disagree with the math or physics behind the 20" barrel as described by Mist Wolf, however I find that the 18" barrel has far more practical advantages (yes just that 2" alone) for my particular purposes.
Disregarding the statistics we can come up with on paper, my practical experiences (seat of the pants testing) tells me that any perceived trade off for velocity, reliability etc, etc, etc, that a 20" barrel may have over say an 18" barrel is for all ballistic / reliability purposes, non-existent. However losing that extra 2" off the end of the barrel, makes my life as a DM, sniper, counter sniper, etc, much easier. Yes just 2" is a big difference.
As far as ballistics, well.....I am only going to be truly effective up to a certain point with the .223/5.56 so any velocity loss as far as overall distance is concerned is meaningless. Any loss in rotational speed at the muzzle for stability is a moot point IMO from 20" to 18" as I am going to chose my own ammo. While there is a difference, I have also not seen that huge of a difference in weights from 55gr to 77gr out to a good effective range, however I will opt for the 75-77gr. At such long distances the most desired effects of the .223/5.56 are lost at extreme ranges anyway. Still don't want to get hit by one from say 900-1000 yards.
So my point, heck I would build one as they are cool as heck to me. But 20" wouldn't be my personal choice to use as a tool. If I am not worried about distance I would be using a carbine. If I was using it as a reach out and touch someone rifle that I had to maneuver around, I would opt for 18". In reality, if I was worried about precision distance shooting, it wouldn't be the .223 / 5.56 to begin with. ;)
I like one of mine:
Colt flat top 20" w/pencil barrel, DD lite, ARMs 40L, Acog w Dr Optic, BAD lever, x300 and A2 stock.
No fuss, no muss.
I'd probably go with a SAM-R w/ A5 and Nightforce 2.5-10x, and a Lightweight 20" with DD OmegaX 12" and ACOG. Not the most exciting, but both would perform.
As my long setup builds up, I'm pretty much doing that, but with an 18" MedCon, MR/T, and A5.
ford7379trucks
08-21-10, 05:16
My favorate. bone stock SP1 but ill get out voted here. I just like the retros for a full size fun gun. You already have a carbine Now if its a long range sniper gun id go 308. I like the reaction you get from they guys that have been around at the range when this young kid pulls out the gun they had as a kid and wish they hadnt sold it for dippers. :sarcastic:
decodeddiesel
08-21-10, 10:47
Well, I've got KAC on my mind so I will change things up a bit.
20" HBAR rifle gas system, chopped as short as possible so it will still reliably cycle everything from Wolf crap to M855 and MK 262 MOD 1. Probably 17" or 18", target crown. Then dimpled for weight reduction, pinned gas block, etc. Triple Tap, NT4 Suppressor.
KAC URX-II Rifle Length. Light weight, removable bottom rail for barrel cleaning, integral BUIS to me present a better sight picture than a fixed FSB.
KAC Ambi Lower with a VLTOR A5 Buffer tube and their special rifle buffer system. LMT SOPMOD.
KAC 600m BUIS, TA11G, PVS-15, SF Scout in offset mount...
take this FWIW but until I ran a midlength for a while, I really didn't appreciate all the hoopla.
then, after using my midlength and Lightweight midlength back-to-back in a class, that's when the lightbulb started to glow dimly.
as everyone else says, don't put any crap on your rifle till you've run it hard and see what works for you. for me, it's all about hand position and balance and all of my current carbine lengths will get gasblocks and 10" or longer rails.
in the future, unless I have a specific need for the heavier profile of the govt. model, I'm only going to be buying LW Middies from now on...
rrpederson
08-21-10, 22:03
my ideal 20" rifle would have been the one i was issued in the marine corps. i had an m16a4 equipped with a ta31f acog. knights rail forend with a flat top upper. the 3 round burst option wasn't all that necessary, but this is an "ideal" thread. the one i had was very accurate for military standards and never had a single hiccup.
richie
motorwerks
08-22-10, 01:51
I already have most of my ideal 20incher (chicks dig it).......
1/9 Bushmaster Hbar (I would rather it was 1/7, or 1/8 but I really dont shoot heavy enough bullets yet to bother), S&W lower (Its what I could get at the time, not that it maters they are all about the same LOL), Bushmaster A2 Upper (I got a screaming deal), Young Manufacturing NM BCG, Rock River 2 stage trigger, Colt Stock, Some unknown take off handguard. The only thing I really want to change is that I would like to add one of the sneaky under the A2 handguard free float tubes.
Well, the A2 stock has to go, replace with either the new Vltor or with a Sully fixed. The front sight tower has to go too; free float 11" or 13" rail, like a Troy TRX. A 2.5-10X would be nice. Oh yeah, no 20" barrel; an 18" government profile is more than plenty.
I like it simple
http://i567.photobucket.com/albums/ss111/denimtalk/LMTBCMNoveske-1.jpg
variablebinary
08-22-10, 03:43
Take a regular Marine M16-A4 and add a Cavalry Arms type A1-ish length stock.
Perfect!
Take a regular Marine M16-A4 and add a Cavalry Arms type A1-ish length stock.
Perfect!
bushmaster government profile barrel 1-7
A1 stock.
i love it.
peabody
I really like the full size AR15 rifles with their 20" barrels and fixed stock...I know, I know, it is not cool these days but please indulge me. In the interest of full disclosure, my go to long gun at home is a Colt 6920; so yes, I am aware that what I like may not be the most practical...
With that said, I would like to know what you think would be the ideal full size AR15...only conditions that it must have a 20" barrel (any contour) with full length DI gas system and be chambered for 5.56x45mm...anything else is up to you...what would you do?
If you can live with an 18" rather than a 20", I think this one shoots pretty straight.
It's wicked accurate too.
http://www.mdshooters.com/gallery/files/4/4/4/1/9.jpg
Grumpy MSG
10-07-10, 19:15
MistWolf said:
A 1:7 twist isn't as necessary to stabilizing longer bullets in a 20" barrel as it is with a 14.5". 20" barrels attain greater velocity and the bullet will exit the muzzle at a higher RPM. It's the RPM that stabilizes the bullet, not twist rate.
I am going to have to hit the B.S. button on that one. With an M16A1, at one hundred yards with 62 grain green tip M855 ammo at Quantico MCB I observed a target where bullets fired from the 100 yard line went through the target in an about 18 inch group and several of the rounds went through through the target dead sideways...
As far as for my perfect full size rifle: A2 Buttstock, A1 pistol grip, Geissele SSF trigger, Flat-top upper with a Daniel Defense Omega rail system, a good shooting FN M16A4 barrel, Tango Down bipod, Trijicon TA31RCO-A4 ACOG, AN/PEQ-15 laser designator and MK262 ammo.
I'm really thinking about buying one of those FN A2 uppers that are floating around and mating it with a BCM A2 lower.
That would be my ideal 20", since my only use for one would be a plinker and the nastalgia of my old issue weapon. Might have to forgoe the three point sling thought.
I am going to have to hit the B.S. button on that one. With an M16A1at one hundred yards with 62 grain green tip M855 ammo at Quantico MCB I observed a target where bullets fired from the 100 yard line went through the target in an about 18 inch group and several of the rounds went through through the target dead sideways...
What is your point of that story? The M855 was designed for the A2, not the A1 with it's 1:12" twist rate.
Anyways, my ideal full size AR would also be a clone of the M16A4 that was issued to me way back.
Magic_Salad0892
10-08-10, 05:59
FailZero Nickel Boron Upper Receiver
FailZero Nickel Boron Charging Handle + PRI Flat Latch (''Gas Buster'' Silicon mod.)
FailZero Nickel Boron Coated Hammer
FailZero Nickel Boron Coated Bolt Carrier
LMT Enhanced Bolt
Daniel Defence CHF 20'' 1:7 + Noveske Switchblock (20'' rifle)
KAC Rifle Length URX
KAC Match Trigger
KAC Micro 200-600m Rear sight
KAC M4 Flip Up Front Sight
KAC Triple Tap
KAC QDSS-NT4
AN/PEQ-15
A1 Stock
A1 Pistol Grip
S&B Short Dot (1-8X)
Magpul 20 round PMAGS (Black)
Mk. 262 Mod. 01 or Nosler 77 gr. Custom Competition Handloads.
Some form of bipod. :)
Grumpy MSG
10-08-10, 17:29
JC0352, MistWolf said:
A 1:7 twist isn't as necessary to stabilizing longer bullets in a 20" barrel as it is with a 14.5". 20" barrels attain greater velocity and the bullet will exit the muzzle at a higher RPM. It's the RPM that stabilizes the bullet, not twist rate.
My point was, heavier bullets, actually it's longer bullets, need a faster rate of twist. The use of 1:7 by the Military was actually because of the length of the M856 tracer. 1:9 will stabilize rounds up to about 68-70 grains. Some 1:9 barrels will work with the 77 grainers, others won't. In that respect it is a calculated risk at best.
This, but with a 12" Lite rail:
http://www.545ar.com/bcms.jpg
Def 12" Lite over KAC (weight), also with a Miad, TA11JG, SF Scout, offset T-1 depending on mission, Kac micro 600m rear sight, kac vfg, maybe even kac flip front and chop the fsp
JeepDriver
10-08-10, 18:38
While I'm more of a 16" and under kind of guy, I needed a rifle. This is what I came up with.
http://www.fototime.com/B8A6730717EBC7F/standard.jpg
20" 1:7 CMMG upper (BCM or Colt upgrade sometime)
RRA lower (engraving by Harford Engraving Service)
DD 12" Rail
A2 stock
RRA NM LPK
TA31 in LaRue mount
Assorted MagPul and LaRue accessories.
I for the life of me cannot do a 556 in my 'ideal.' 300AAC-blackout: 123gr and PMags. ACOG with Docter optic. SOPMOD stock of course. DD Lite rail.
DocCasualty
10-08-10, 19:44
I really like the full size AR15 rifles with their 20" barrels and fixed stock...I know, I know, it is not cool these days but please indulge me. In the interest of full disclosure, my go to long gun at home is a Colt 6920; so yes, I am aware that what I like may not be the most practical...
I'm with you, it's still a great rifle! What's impractical about that? Me, a Colt Sporter Target Rifle. What a semi-auto AR15 was meant to be.
With that said, I would like to know what you think would be the ideal full size AR15...only conditions that it must have a 20" barrel (any contour) with full length DI gas system and be chambered for 5.56x45mm...anything else is up to you...what would you do?
Stoner designed it, Colt has played with it. I'm pretty happy with that A2 pattern myself. KISS - great principle!
the SAM-R, SDM-R and SPR (though 18") variants are excellent examples of where the rifle length AR can be taken.
some links here http://designatedmarksman.com/the_rifle.shtml
JC0352, MistWolf said:
My point was, heavier bullets, actually it's longer bullets, need a faster rate of twist. The use of 1:7 by the Military was actually because of the length of the M856 tracer. 1:9 will stabilize rounds up to about 68-70 grains. Some 1:9 barrels will work with the 77 grainers, others won't. In that respect it is a calculated risk at best.
Oh okay. Thanks for the clarification.
...I am going to have to hit the B.S. button on that one. With an M16A1, at one hundred yards with 62 grain green tip M855 ammo at Quantico MCB I observed a target where bullets fired from the 100 yard line went through the target in an about 18 inch group and several of the rounds went through through the target dead sideways...You can hit the BS button all you want. I'll say it again- the laws of physics do not change because we have an AR. 20 inch barrels give more velocity than 14.5 inch barrels. More velocity with the same twist means more bullet RPMs. A 1:7 twist in a 20 inch barrel isn't as important as it is in a 14.5" barrel. A 1:9 may do fine. Nor did I suggest the 1:12 would be a suitable substitute as it would not impart enough RPMs to the longer bullets with 5.56 velocities. Might work in a 22-250 or a 220 Swift. But you won't know for sure until you try it.
Since you said:
JC0352My point was, heavier bullets, actually it's longer bullets, need a faster rate of twist. The use of 1:7 by the Military was actually because of the length of the M856 tracer. 1:9 will stabilize rounds up to about 68-70 grains. Some 1:9 barrels will work with the 77 grainers, others won't. In that respect it is a calculated risk at best....which is about what I said, let me push that mean ol' BS button for ya :big_boss:
Take a regular Marine M16-A4 and add a Cavalry Arms type A1-ish length stock.
Perfect!
That would be better, but something even shorter would be ideal. The A2 stock is just insanity. I'm about 5' 9" with long arms and it sucked for me. Watching our small females try to qualify with those muskets was frustrating.
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