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6/21/2017 8:25:40 PM
Posted: 3/1/2010 1:07:13 PM EDT
Hi, I've been rethinking how I'm going to get my first AR. Right now I'm thinking of either getting an upper and complete lower from DSArms with an m4 barrel, or building an HBAR carbine from a Del-ton kit.

My question is this: will the thickness of the barrel make a noticeable difference in accuracy if I'm shooting within 100 yards? I've heard from a lot of sources that the m4 barrels aren't as accurate because they're kinda thin under the handguards.
Link Posted: 3/1/2010 1:10:03 PM EDT
What is the overall goal of this setup you're purchasing?
Link Posted: 3/1/2010 1:11:18 PM EDT
Originally Posted By migkillertwo:
Hi, I've been rethinking how I'm going to get my first AR. Right now I'm thinking of either getting an upper and complete lower from DSArms with an m4 barrel, or building an HBAR carbine from a Del-ton kit.

My question is this: will the thickness of the barrel make a noticeable difference in accuracy if I'm shooting within 100 yards? I've heard from a lot of sources that the m4 barrels aren't as accurate because they're kinda thin under the handguards.


It isint just M4 barrels, any govt. profile barrel is thin under the handguards...
Link Posted: 3/1/2010 1:13:49 PM EDT
Originally Posted By RedWagon:
Originally Posted By migkillertwo:
Hi, I've been rethinking how I'm going to get my first AR. Right now I'm thinking of either getting an upper and complete lower from DSArms with an m4 barrel, or building an HBAR carbine from a Del-ton kit.

My question is this: will the thickness of the barrel make a noticeable difference in accuracy if I'm shooting within 100 yards? I've heard from a lot of sources that the m4 barrels aren't as accurate because they're kinda thin under the handguards.


It isint just M4 barrels, any govt. profile barrel is thin under the handguards...


Yeah, I've hard, but I also heard from a del-ton sales rep that their 16" rifle kits are thick under the handguards

Regarding the goal for this setup, its mostly going to be a range toy and a home defense gun (and maybe, just maybe, a zombie killer if SHTF)
Link Posted: 3/1/2010 1:22:54 PM EDT
Originally Posted By migkillertwo:
Originally Posted By RedWagon:
Originally Posted By migkillertwo:
Hi, I've been rethinking how I'm going to get my first AR. Right now I'm thinking of either getting an upper and complete lower from DSArms with an m4 barrel, or building an HBAR carbine from a Del-ton kit.

My question is this: will the thickness of the barrel make a noticeable difference in accuracy if I'm shooting within 100 yards? I've heard from a lot of sources that the m4 barrels aren't as accurate because they're kinda thin under the handguards.


It isint just M4 barrels, any govt. profile barrel is thin under the handguards...


Yeah, I've hard, but I also heard from a del-ton sales rep that their 16" rifle kits are thick under the handguards

Regarding the goal for this setup, its mostly going to be a range toy and a home defense gun (and maybe, just maybe, a zombie killer if SHTF)


Unless your doing hard core training or shooting 500 meters, It will be fine.
Link Posted: 3/1/2010 1:25:59 PM EDT
If it's a bench gun get the HBAR.

Anything less then that I prefer a govt profile barrel.

Link Posted: 3/1/2010 1:29:56 PM EDT
Originally Posted By migkillertwo:
Originally Posted By RedWagon:
Originally Posted By migkillertwo:
Hi, I've been rethinking how I'm going to get my first AR. Right now I'm thinking of either getting an upper and complete lower from DSArms with an m4 barrel, or building an HBAR carbine from a Del-ton kit.

My question is this: will the thickness of the barrel make a noticeable difference in accuracy if I'm shooting within 100 yards? I've heard from a lot of sources that the m4 barrels aren't as accurate because they're kinda thin under the handguards.


It isint just M4 barrels, any govt. profile barrel is thin under the handguards...


Yeah, I've hard, but I also heard from a del-ton sales rep that their 16" rifle kits are thick under the handguards

Regarding the goal for this setup, its mostly going to be a range toy and a home defense gun (and maybe, just maybe, a zombie killer if SHTF)


I doubt you'd notice a difference in accuracy, unless you're handloading and shooting at very long ranges (ie much farther than 100y). You might as well get the M4 barrel and have a lighter rifle.
Link Posted: 3/1/2010 1:33:36 PM EDT
I am the minority here as I prefer the Hbar. The M4 will do fine but for most accuracy allow for proper cooling between rounds and you will be fine. The added weight of a Hbar just doesn't bother me. Good ;Luck.
Link Posted: 3/1/2010 2:24:06 PM EDT
Originally Posted By MillerSHO:
If it's a bench gun get the HBAR.

Anything less then that I prefer a govt profile barrel.



Agree.
Link Posted: 3/1/2010 2:29:22 PM EDT
[Last Edit: 3/1/2010 2:40:04 PM EDT by Catman2]
Prolly won't make a difference off the bench but shooting offhand an Hbar will be more stable thus you won't miss as often. If you carry it long hours between shooting, i.e., patrols or hunting the Gov. profile will be lighter but with a sling my 16" Hbar's weight wasn't a problem not to mention when it came time to shoot, in my case hogs, it was deadly solid on target. In other words I'd rather carry more weight all day and be able to make the shot then carry something lighter and blow it.

Having said that my Gov. profile is pretty damned stable
Link Posted: 3/1/2010 2:34:05 PM EDT
Originally Posted By NCHornet:
I am the minority here as I prefer the Hbar. The M4 will do fine but for most accuracy allow for proper cooling between rounds and you will be fine. The added weight of a Hbar just doesn't bother me. Good ;Luck.


+1
Link Posted: 3/1/2010 2:52:26 PM EDT
I compromised and went SOCOM weight..lighter than HBAR and heavier than regular M4 profile.15 to 20 rds per minute should not bother accuarcy or get the barrel hot enough to bother it.HBARs take heat better and will stay accuarte longer and hotter than a lighter barrel but it also takes longer too cool down.Just remeber we have semi auto single stage AR15s..most of us dont shoot full auto where accuarcy can really be effected when things heat up way way faster than semi only will.
Link Posted: 3/1/2010 3:01:22 PM EDT
Originally Posted By ChromeLined:
I compromised and went SOCOM weight..lighter than HBAR and heavier than regular M4 profile.15 to 20 rds per minute should not bother accuarcy or get the barrel hot enough to bother it.HBARs take heat better and will stay accuarte longer and hotter than a lighter barrel but it also takes longer too cool down.Just remeber we have semi auto single stage AR15s..most of us dont shoot full auto where accuarcy can really be effected when things heat up way way faster than semi only will.


IIRC unless I'm mistaken, doesn't slower heat up also help reliability? (Heat being one of the causes of part malfunctions?)

Link Posted: 3/1/2010 3:18:05 PM EDT
[Last Edit: 3/1/2010 3:20:30 PM EDT by ChromeLined]
Yea thats what I meant by takes the heat better as far as heats up slower I guess it depends on rate of fire.Ive gotten HBARs heated up real quick.I think though with barrel heat always being a fctor in any weapon the AR/M16 also gets hot inside the receiver,just as hot as the barrel so betewwen baking off lube and shitting where its eating I think all that with the barrel can contribute to heat related failures.I never shoot faster than I can keep my sights on target wich is about a round every 2 or 3 seconds.If I were in a survival situation dpepnding on conditions maybe I would or would not have to dump ammo out faster.

Ive nenevr been in situations where Ive had to use fire to move but in a situation like that where your laying down fire the HBAR will get real hot too but being thicker it will function longer and stay rigid better as oposed to a lighter barrel and take longer to cool wich may or may not be a factor depending on the situation.One things for sure if heavier barrels werent better for function the Army wouldnt have listed a heavier barrel as a want for interim M4 upgrades " SOCOM BARREL" along with a piston system..so cooler running upper and internals and a barrel that takes heat better.Isit relevant in semi-auto only operation well we dont really know unless we have some data from say contractors or others who have used semi onlys in prolonged firefights in afghanistan or Iraq and what type of barrel was used.As far as I know right now only SF M4A1s have the heavier med weight Socom barrel.
Link Posted: 3/1/2010 3:37:13 PM EDT
You know, with all this talk of heating/cooling, stiffness and weight, I'm thinking that the 'mutt' carbine I put together in 1995 (or so, don't remember the exact year) actually was pretty smart. It was a Bushmaster lower with a M16A1 stock. The A2 upper was a 'K' (Kaiser Aluminum) but I don't know who machined and finished it. The BCG was Bushy and the barrel was an Olympic 16" full-heavy, fluted, 5.56 and not chrome-lined that I found at a gun show at one of those tables where they build your gun right on the spot. This carbine worked great and shot straight. The fluting on the barrel was very deep and it really didn't weigh that much. Most of the weight was under the handguards, and with the fixed stock w/cleaning kit in the rear it handled very well. I never fired it enough to heat up the barrel, but I think it would cool off rather quickly. The good news is, its still in the family. My son in GA has had it for several years. Even though he has a different AR and is thinking of a .30 caliber, he will never give up the 'mutt'! I put a 6-position stock on it at some point.

Link Posted: 3/1/2010 3:40:20 PM EDT
I think going with a free float hand guard will have a greater impact on accuracy than HBAR vs. Govt. profile.


Get govt or M4 profile and then add a free float hand guard, you'll be good to go...
Link Posted: 3/1/2010 3:41:24 PM EDT
Fluted barrels are awesome..I dont like the look of fluting but with the scalopped grooves you get just as much barrel stiffness and actually more surface area than it would have had even as an HBAR so it cools like a lightweight barrel.So like an HBAR fluted barrels give the same benefits with less weight and quicker cooling.
Link Posted: 3/1/2010 4:04:02 PM EDT
Many don't like fluted barrels but seem to like the 'dimpled' ones. I like the flutes - there's no question they remove more weight and provide more surface area than dimpling. Dimpling to me is strictly a cosmetic effect. That mutt I made is the only AR I have shot that hit the center at 25 yds with the aperture on the center line of the index. That actually speaks not to my assembly but of the man who built the upper. Plus, like Olympic or not, the one thing they always did well was barrels, and this one is no exception.
Link Posted: 3/1/2010 4:58:29 PM EDT
Link Posted: 3/1/2010 5:08:37 PM EDT
Originally Posted By migkillertwo:My question is this: will the thickness of the barrel make a noticeable difference in accuracy if I'm shooting within 100 yards?


No.

Link Posted: 3/1/2010 5:33:09 PM EDT
You guys are such AR snobs, I haven't been able to pull the trigger on my first AR but I will soon!
You guys are having way to much fun! Seems like crack and I don't want that first rock! I'm afraid!
I hope the zombies don't come before do it!
Link Posted: 3/1/2010 5:45:49 PM EDT
[Last Edit: 3/1/2010 5:46:38 PM EDT by Captains1911]
Originally Posted By ChromeLined:
Fluted barrels are awesome..I dont like the look of fluting but with the scalopped grooves you get just as much barrel stiffness and actually more surface area than it would have had even as an HBAR so it cools like a lightweight barrel.So like an HBAR fluted barrels give the same benefits with less weight and quicker cooling.


Are you suggesting that a fluted HBAR has just as much rigidity as a non-fluted HBAR? If so I would have to disagree, anytime you remove material you are going to lose stiffness. The fluted one will cool faster though.
Link Posted: 3/1/2010 9:23:32 PM EDT
Would also depend on what you are used to. I'm used to carrying a M4A1 (since 95') and when I put a 16" HBAR on my personal carbine, balance is way different. Didn't like it and now my youngest son has it which he loves (I picked up a 14.5" M4 barrel). I also competed with the same M4A1 in Army matches out to 500-600 yds (Mk262) with irons and this is the same M4 that I used on numberous deployments and train ups (approx 20K+).

Carbines are a little tougher to shoot at long range but if you know what your doing, it'll reach out there.


CD
Link Posted: 3/1/2010 9:34:21 PM EDT
I believe rigdity is the same because your only scaloping small trenches not turning down the entire profile to a thinner one so I think rigidity would be the same if not more no?the trenches or flutes are low points but the high points remain I would think those are enough to still provide the same stiffness but less weight in the process.
Link Posted: 3/1/2010 9:43:52 PM EDT
Originally Posted By NCHornet:
I am the minority here as I prefer the Hbar. The M4 will do fine but for most accuracy allow for proper cooling between rounds and you will be fine. The added weight of a Hbar just doesn't bother me. Good ;Luck.


+1
if you keep it KISS the added weight is not a problem.
all I have on mine is a KAC RAS and a small flashlight...I've used it during a dynamic shooting match and the extra weight helped me to deal with the recoil

Link Posted: 3/2/2010 4:42:56 AM EDT
Originally Posted By ChromeLined:
I believe rigdity is the same because your only scaloping small trenches not turning down the entire profile to a thinner one so I think rigidity would be the same if not more no?the trenches or flutes are low points but the high points remain I would think those are enough to still provide the same stiffness but less weight in the process.


Nope, by removing material you are decreasing the sections moment of inertia, or resistance to bending. It's a classic mechanics of materials problem. Whether or not the reduced stiffness has any ill affects is another matter.
Link Posted: 3/2/2010 5:44:24 AM EDT
If you had the same amount of material overall (greater dia) to compensate for the material lost in the flutes then the stiffness would actually be increased! Think flanges of a steel beam being further from the neutral axis! But material removal will result in less stiffness and more bending!
Link Posted: 3/2/2010 6:22:13 AM EDT
[Last Edit: 3/2/2010 6:23:40 AM EDT by Captains1911]
Originally Posted By Anglingarchitect:
If you had the same amount of material overall (greater dia) to compensate for the material lost in the flutes then the stiffness would actually be increased! Think flanges of a steel beam being further from the neutral axis! But material removal will result in less stiffness and more bending!


You are absolutely correct, however in the case of fluted barrels you are not increasing the diameter, you are removing material from a section of fixed inside and outside diameters, thus decreasing it's Ixx and therefor it's stiffness (resistance to bending around the X-X axis).
Link Posted: 3/2/2010 7:07:27 AM EDT
Taking some materiel away from a barrel does not always result in a less stiff barrel. It depends more on where and how the materiel is taken away. If you take the I beam example the I beam has the same strength as solid box beam of the same dimensions, but with a reduction of @ 50% in weight and materiel. The outside most point of the flutes (the top of the flute) is further away from the neutral plane than a smaller diameter light weight barrel so it will be more rigid in that case. Because it has the same distance from the neutral plane as the heavy barrels profile the stiffness should be the same, for the same reason as the I beam vs. the solid beam but with out the weight penalty.

Seems like something for "The Box of Truth" (you know, the guys that actually know WTF they are talking about when it come to debunking firearms myths unlike those tools from SF with a TV show...)
Link Posted: 3/2/2010 7:37:17 AM EDT
[Last Edit: 3/2/2010 7:46:50 AM EDT by Captains1911]
Originally Posted By 4schitzangiggles:
Taking some materiel away from a barrel does not always result in a less stiff barrel. It depends more on where and how the materiel is taken away. If you take the I beam example the I beam has the same strength as solid box beam of the same dimensions, but with a reduction of @ 50% in weight and materiel. The outside most point of the flutes (the top of the flute) is further away from the neutral plane than a smaller diameter light weight barrel so it will be more rigid in that case. Because it has the same distance from the neutral plane as the heavy barrels profile the stiffness should be the same, for the same reason as the I beam vs. the solid beam but with out the weight penalty.

Seems like something for "The Box of Truth" (you know, the guys that actually know WTF they are talking about when it come to debunking firearms myths unlike those tools from SF with a TV show...)


Sorry, but you are wrong. The moment of inertia of a solid box is much greater than that of a beam of similar flange and depth dimensions. Take an HP12x84 for example, which has a depth of 12.3" and a flange width of 12.3", and an Ixx of 650 in^4. Now calculate the Ixx of a solid 12.3"x12.3" box and you'll find that it's 1907 in^4, almost 3 times that of the HP section. Compare the moment of inertia of a hollow pipe to that of a solid circle, and you will see a similar relationship.



Link Posted: 3/2/2010 8:24:36 AM EDT
[Last Edit: 3/2/2010 8:25:33 AM EDT by Plinker1022]
Circulars cross sections such as a tube....such as a barrel is already the most efficient cross section regarding bending. All of the area is located away from the axis of bending and its bending characteristics are the same regardless of what axis you choose. Please remember I said efficient, not strongest or best.....I don't think fluting is going to hurt bending that much one way or another. Considering the increased heat transfer away from your barrel, I think fluting is a great idea. I've sold guns that got hot too quick and stayed hot for too long. I think this thread started as HBAR vs. M4. Wow. I agree Captain, sometimes you gotta pull the physics out.
Link Posted: 3/2/2010 8:32:31 AM EDT
[Last Edit: 3/2/2010 8:34:01 AM EDT by Plinker1022]
I hate too continue on but the square beam theory...fact...etc...you have but although it may be correct its not efficient at all. You quote three times the bending moment but look at area. The square 12.3 x 12.3 = 151.29 in2.

The HP section you provided, 24.6 in2.

So basically six times the area was used to get three times the bending resistance.
Link Posted: 3/2/2010 8:33:25 AM EDT
[Last Edit: 3/2/2010 11:36:34 AM EDT by Captains1911]
Originally Posted By Plinker1022:
Circulars cross sections such as a tube....such as a barrel is already the most efficient cross section regarding bending. All of the area is located away from the axis of bending and its bending characteristics are the same regardless of what axis you choose. Please remember I said efficient, not strongest or best.....I don't think fluting is going to hurt bending that much one way or another. Considering the increased heat transfer away from your barrel, I think fluting is a great idea. I've sold guns that got hot too quick and stayed hot for too long. I think this thread started as HBAR vs. M4. Wow. I agree Captain, sometimes you gotta pull the physics out.


And I agree with you 100%, the benefits of fluting out weigh the minor loss in in bending resistance. I was just correcting the others who were suggesting that there is no loss at all in bending resistance.
Link Posted: 3/2/2010 8:35:38 AM EDT
[Last Edit: 3/2/2010 8:38:29 AM EDT by Plinker1022]
Yep...anytime you take area away from a section's extremities, bending is compromised. Consider an I Beam. Now chop of the top flange. You decreased area by roughly a third but decreased the bending moment by almost half. The area is oriented away from the axis of bending for a reason. Captain, what do you do...I've never seen someone pull out the second moment of area on a gun forum before.
Link Posted: 3/2/2010 8:37:35 AM EDT
[Last Edit: 3/2/2010 8:40:16 AM EDT by Captains1911]
Originally Posted By Plinker1022:
I hate too continue on but the square beam theory...fact...etc...you have but although it may be correct its not efficient at all. You quote three times the bending moment but look at area. The square 12.3 x 12.3 = 151.29 in2.

The HP section you provided, 24.6 in2.

So basically six times the area was used to get three times the bending resistance.


We weren't discussing area and amount of material, but stiffness. This all started when I corrected "Chromelined's" comment about fluting not reducing stiffness, that is all.

Quote:
"Fluted barrels are awesome..I dont like the look of fluting but with the scalopped grooves you get just as much barrel stiffness and actually more surface area than it would have had even as an HBAR so it cools like a lightweight barrel.So like an HBAR fluted barrels give the same benefits with less weight and quicker cooling."
Link Posted: 3/2/2010 8:40:00 AM EDT
[Last Edit: 3/2/2010 8:41:44 AM EDT by Plinker1022]
Originally Posted By Captains1911:
Originally Posted By Plinker1022:
I hate too continue on but the square beam theory...fact...etc...you have but although it may be correct its not efficient at all. You quote three times the bending moment but look at area. The square 12.3 x 12.3 = 151.29 in2.

The HP section you provided, 24.6 in2.

So basically six times the area was used to get three times the bending resistance.


We weren't discussing area and amount of material, but stiffness. This all started when I corrected "Chromelined's" comment about fluting not reducing stiffness, that is all.


I know. I understand. I just can't help but think with efficiency in mind. You know this economy has got everything thinking efficiency around here. What field you work in? I've never seen someone pull out the second moment of area on a gun forum before.

Link Posted: 3/2/2010 11:11:04 AM EDT
Captains1911 must be an engineer or had training in it! I'm an Architect so we have these discussions with our Structural Engineer all the time about Structures~~~~ Barrels not so much but the physics is still the same.
Link Posted: 3/2/2010 11:11:10 AM EDT
I recently bought a 16" carbine HBAR upper. It's going to be my abuse upper. Little cleaning & lots of rapid fire mag dumps.
Upon putting it on my lower I did notice the weight difference. It's not much but you do feel it. Adding an eotech & MBUS balanced it out a little.
Under the had guards is THICK. There's almost no space between it & the gas tube.
Link Posted: 3/2/2010 11:33:45 AM EDT
[Last Edit: 3/2/2010 11:34:07 AM EDT by Captains1911]
Originally Posted By Anglingarchitect:
Captains1911 must be an engineer or had training in it! I'm an Architect so we have these discussions with our Structural Engineer all the time about Structures~~~~ Barrels not so much but the physics is still the same.


Link Posted: 3/2/2010 12:25:25 PM EDT
Originally Posted By 1saxman:
Many don't like fluted barrels but seem to like the 'dimpled' ones. I like the flutes - there's no question they remove more weight and provide more surface area than dimpling. Dimpling to me is strictly a cosmetic effect. That mutt I made is the only AR I have shot that hit the center at 25 yds with the aperture on the center line of the index. That actually speaks not to my assembly but of the man who built the upper. Plus, like Olympic or not, the one thing they always did well was barrels, and this one is no exception.


dimpling, when done properly(knights) removes more weight, is more rigid, and offers more cooling than fluting. Its better in every aspect which is why they do it. I doubt knights does stuff soley for looks.
Link Posted: 3/2/2010 12:29:45 PM EDT
[Last Edit: 3/2/2010 12:32:34 PM EDT by Plinker1022]
Originally Posted By Captains1911:
Originally Posted By Anglingarchitect:
Captains1911 must be an engineer or had training in it! I'm an Architect so we have these discussions with our Structural Engineer all the time about Structures~~~~ Barrels not so much but the physics is still the same.




Yeah I jumped over from the private side to a public utility about 2 years ago so it's been a long time since I actually practiced...engineering that is....I shot off about 200 yesterday.
Link Posted: 3/2/2010 1:05:25 PM EDT
16" Midlength Govt. Profile 1:7" Chrome Lined.

or

20" Govt. Profile 1:7" Chrome Lined.

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