Why Are ARs So Heavy?

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My competition rifle weighs about 8.25 pounds scoped, but empty. Most people who pick it up think that it is lighter, as it balances very well.

I've cut pretty much every bit of fat from my rifle - it sports a Cav Arms A1-length fixed stock, a PRI lightweight carbon fiber float tube, no rails, no iron sights, a lightweight bolt carrier and buffer, etc. I could probably knock off about a pound by replacing the 17" medium-profile barrel with a 16" lightweight, but I'm not going to. I like the full length gas system, and I like having enough mass in the barrel to retain some mid-range accuracy when it gets hot. I could also knock off a pound or more by replacing the scope with iron sights, and I'm not going to do that either. Optics are more capable than irons, puento finale.

Point being, the weight of an AR, or any rifle, will depend on the function for which it is constructed.

- Chris
 
Anybody who ever fired the old M16A1 rifle SHOULD know darn well why the later models have heavier barrels on them.

The M16A1 had a light barrel, and weighed less than 6.4 lbs. empty.

However, because of the light barrel, the muzzle lift was excessive. Especially in full auto mode. Too much muzzle lift meant impeded handling and slower follow-up shots, which are NOT good in combat.

The heavier barrel on the M16A2 and other subsequent models, resulted in noticeably less muzzle lift, thus improving handling and speeding up follow-up shots.

Lighter is not always "better" when it comes to firearms.
 
I don't really know anything about ARs, I've never even handled one.
However, there is something to be said about weight.
For at least me, accuracy increases with weight, even if the recoil is already nil.
With a heavy rifle in my hands, my sight picture drifts less. The weapon sits like a rock in my hands. It's a very comforting feeling, and it helps accuracy quite a bit.
Now, I reckon that comfort would turn to annoyance at about 10 lbs, but I can see a 7.5-8.5 lbs rifle being quite the sweet spot for weight and such.
So a heavier AR would probably create the same phenomenon.
Just my $2
 
A better question. Why do people choose to get an M4 profile barrel?
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Because it's lighter than an HBAR, but is still heavy enough that it won't heat up quickly and cause a POI shift. It's also become a standard offering, so many people go with it because that's what's on many carbines on dealer shelves.
Because there are all those M203s floating around out there, of course.
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Is that why others choose standard government profile A1 or A2 bbls, or lightweight carbine length bbls? You can mount M203s on those too, you know.
 
to start with i'm definitely in the camp that says "b/c it takes less labor and money to make an HBar" and also that since in most cases the furthest an AR will be carried by teh typical owner is from the trunk to the bench, no one is all that worried about the weight trade off.

To bad many of us can't shoot even a pencil barrel to it's potential.
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I've been trying to do just that, but it seems my luck with such things has run out and i've gotten a dog of an HBAR!

about 2-2.5 years ago i built an A1 near-clone for my wife and as a shortcut used an Oly "Plinker Plus 20" upper. i should have known but never guessed that dern thing would have an HBAR barrel (for whatever reason, i was expecting it to be the same Dia. end to end, not larger under the handguard). well after over 800rds down range and breaking down and sandbagging that thing in to take as much of the "human variable" out and see what IT is capable of. i'm convinced the barrel is a POS

i'm getting benched 8" groups at 50yrds, and i've been lead to beleive an AR should be shooting 3-4" or less at 100, ie 3-4MOA IS the pass fail standard for a US service rifle isn't it??

so in other words i've got an overweight rifle with accuracy worse that some pistols i've owned.

anyone know if the A1 profile barrels from CMMG are any good accuracy wise? or at least capable of doing better than 8" at 50yards....?
 
A heavy gun is a Garand . That's a real gun. Reach out with some authority.
 
I'm glad I read this thread. I had no idea that these rifles weighed that much. Makes me appreciate the HK93 even more.
 
Posted by stubbicatt:
I'm glad I read this thread. I had no idea that these rifles weighed that much. Makes me appreciate the HK93 even more.
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I take it you've never owned an HK93. They weigh in at 8.4 lbs. with an empty magazine. ;)
 
My Carbon15 weighs a little over 5 pounds. I have no problem carrying it for any length of time.
 
Someone else compared an AR to the SKS. I owned an SKS before I owned an AR. Therefore, I don't think my AR is "heavy" at all! ;)
 
anyone know if the A1 profile barrels from CMMG are any good accuracy wise? or at least capable of doing better than 8" at 50yards....?
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8" groups at 50 yards? Something is wrong! Have you checked the barrel nut to make sure that the barrel is in there tight? What ammo are you shooting out of the 20" and what twist rate is the barrel? If you're running some hot 55 grain stuff through a 1 in 7 barrel you might be able to get groups like that. Just a guess though.

I have a Busnmaster pencil 16" barrel which I really like. It's all chrome lined - bore and chamber and shoots reasonably accurately for what it is. I can't tell the difference between it and my 14.5" so far but the farthest I've shot the pencil is 200 yards, whereas I've shot the 14.5" gov't profile out to 400. No problems hitting a 6" square at 100 yards with the pencil barrel and even does reasonably well at 200 with irons and Eotech.
 
The HBAR barrel makes no real difference in weight. An M16A2 with a government profile barrel has a listed weight of 8.43 pounds. A HBAR A2 configuration AR has a list weight of 8.6 pounds. That is a difference of .17 pounds. That's about 2.75 ounces. I own an A4 HBAR with a carry handle sight and have carried an M16A2 (which naturally has the gov profile rifle)- in all honesty, I don't feel any difference between the two as far as weight is concerned and they both hold equally. I regularly use my AR for falling plate competitions, with the .22 conversion kit installed. I can move that rifle faster than most people who use 10/22s in lightweight target configurations- nearly all of which have optics.
 
8" groups at 50 yards? Something is wrong! Have you checked the barrel nut to make sure that the barrel is in there tight? What ammo are you shooting out of the 20" and what twist rate is the barrel? If you're running some hot 55 grain stuff through a 1 in 7 barrel you might be able to get groups like that. Just a guess though.
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Nope everything's tight, not only has this thing been through Oly's QC Dept. twice to get all that checked, once when they made it, and a 2nd time when i sent it back to have the barrel re-indexed b/c it took full left windage (apperture hard against the side of the channel) to bring POI to POA. i had it checked over by the local AR guy to see if anything was out of wack.

ammo and twist rate; Oly lists the plinker plus series as being 1in9, the majority of teh ammo has been early 90's headstamped Radway Green, so 62gr.

but regardless an AR should shoot better than what this thing is
 
Let's all hike 120 miles with packs and come back to this thread
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If I had to run more than a block after a suspect, I would hop back into my squad and run the SOB over. (well, okay, not run over, but you catch the drift of that)

120 miles? Too old, too heavy. Can't fix the former, keep trying to fix the latter. :eek:

The Doc is out now. :cool:
 
The heavier barrel on the M16A2 and other subsequent models, resulted in noticeably less muzzle lift, thus improving handling and speeding up follow-up shots.
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I think the removal of the bottom slot on the A2's flash hider did just as much to cut down on muzzle rise as the heavier barrel did.
 
I think the removal of the bottom slot on the A2's flash hider did just as much to cut down on muzzle rise as the heavier barrel did.
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You're entitled to your opinion.

I've personally fired A2's with the IDENTICAL A1 "birdcage" flash hider on them, WITHOUT the bottom slot removed---and STILL found that the A2 has noticeably less muzzle rise than the A1.

That would clearly indicate to me that the heavy barrel made the primary difference. ;)
 
The A2 flash hider isn't a muzzle brake. There are no slots in the bottom so that the gasses don't blow dust in the air in front of you when firing low to the ground.
 
Posted by cracked butt:
The A2 flash hider isn't a muzzle brake. There are no slots in the bottom so that the gasses don't blow dust in the air in front of you when firing low to the ground.
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Would you agree that the heavier barrel was primarily responsible for the decrease in muzzle rise on the A2? :)
 
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