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JTR8541
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Posted: 7/18/2004 5:10:10 AM
Just a thought.

My local range had their High Power Match today and it just got me wondering. If there isn’t really any accuracy enhancement features between the A2 contour barrel and a heavy barrel, why do match shooters all use heavy barrels.

Not that this matters in what I call reality. All I need for shooting tin cans in a rock pit is A barrel. I’m not a High Power shooter, just curious what they gain in shooting with a heavy barrel.

Thanks, J
FishKepr
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Posted: 7/18/2004 6:27:52 AM
[Last Edit: 7/18/2004 6:39:59 AM by FishKepr]
I'm sure someone else can address the inherent accuracy factor much better than I can so I'll discuss ergonomics..

Heavier rifles hang MUCH better in the offhand stage, dampening out the wobble factor. They're also more stable during the 'rapid' stages. If your rifle doesn't bounce around, you recover faster and are less likely to crossfire. I've seen matches won and lost because of crossfires.

Not only do HP shooters use heavy barrels, it's a standard practice to add weights to make them even heavier. Rifles that weigh 15 pounds or more are common on the line.
JoeInCT
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Posted: 7/18/2004 7:54:02 AM
I have also read that, for those match shooters who want to tweak and micromanage every variable that affects accuracy, a heavy barrel will theoretically "droop" less than a light barrel once it heats up, since there is more mass to absorb the heat.

That goes to a level of concern far beyond what I expect from my rifle, however.
Str8shot
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Posted: 7/18/2004 1:23:43 PM
Besides the fact that a heavy barrel is more inherently accurate than a light one - more mass = stiffness = less whip, less vibration, less heat-induced zero wander, there is another factor that makes the heavy barrel preferable for competition shooting in most venues.

Service Rifle competitors do not hold over for elevation nor do they hold into the wind between the 200, 300, and 600yd. stages typically found in their match. They will record their sight adjustments, then 'count clicks' when moving across the course to shoot at the different ranges.

This requires a very precise repeatability with virtually no loss of zero due to something like the barrel heating found in a lightweight that could cause them to throw shots, especially during the rapid fire stages.

I compete in NRA/CMP Service Rifle and find a properly made heavy NM barrel to be a necessity in order to stay competitive.

All that said, I much prefer the Gov't profile barrels in my A2 and A4 clones for ANY kind of field use, and actually feel less than comfortable when toting an HBAR around anywhere other than the range.
Troy
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Posted: 7/18/2004 4:54:18 PM
HBAR or bull barrels DO matter, but ONLY when you start with a match-quality barrel blank that is precisely chambered to an exact spec, and then free-floated and shot exclusively with perfectly loaded match ammo. It might give you .05 MOA advantage (fired from a mechanical rest, removing the human factor). In a match competition, that little bit of advantage is important.

For the other 99.99% of people, that much accuracy difference wouldn't even be noticable, especially if you aren't shooting from a rest. Combat shooting is far removed from match shooting.

Try this exercise, which is often done at shooting schools. Find an object about 10' away from you at waist height, and hold your rifle on it. For FIVE STRAIGHT MINUTES; never dropping the muzzle off the target. This simulates holding a gun on a prisoner, which may have to be done for 20 or 30 minutes in the real world. Now tell us if a lightweight barrel might be important.

-Troy
Ammo FAQ: www.ammo-oracle.com
(Old) Mag FAQ: magfaq.tripod.com
Barrel? Go CHROME or go home.
macro
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Posted: 7/18/2004 5:43:03 PM
A match grade HBAR will offer better harmonic qualities than a lighter piece of metal, however the gain in accuracy would be hard to demonstrate on a target....maybe in a computer simulation, but not in real life. Other things that factor into it (theorhetically)..weight, the heavier the less movement which lends itself to consistent groups....cooling, the HBAR will distort a little less from heat buildup, which will affect the accuracy...

It's my opinion...but once you get into the match grade barrels and picky handloads...its more about skill than the hardware....most high quality rifles are more accurate than the operator...a $3000 Les Baer custom shop certified 1/4MOA rifle is about as useful as a $500 used Olympic Arms assembly line AR with 5000 rounds through it already, unless the shooter has the skill to demonstrate the difference.

MaverickMkii
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Posted: 7/18/2004 5:46:03 PM
Get the A2 Gov't profile barrel. There is a LOT of felt difference in weight, and Gov't profile balances/handles much better.
Forest
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Posted: 7/18/2004 7:50:12 PM

Originally Posted By JTR8541:
enhancement features between the A2 contour barrel and a heavy barrel, why do match shooters all use heavy barrels.



Just as all dogs are not shepards, not all HBARs are 'Match Barrels'. The inherance accuracy in a mass production 'off the rack' barrel does not see statistically significant improvement between it's HBAR version and the LW version for most shooting (do lots of rapid fire and the HBAR is a bit better - but that kind of shooting isn't precise anyway and the LW offers better handling in those situations).
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model927
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Posted: 7/18/2004 8:27:39 PM
[Last Edit: 7/18/2004 8:29:20 PM by model927]
Lets not forget that the new M4 barrels on the SOCCOM M4A1 are HBARs and I dont hear those guys complaining about weight.The new M4 barrels are machined only in the 2 spots to attach the M203 wich makes the new M4 barrel about 3 or 4 ounces lighter than a civilian HBAR 14.5 so the weight is realy not a factor.Other M4s of course not used by soccom still have a lighter weight profile.As far as what TROY says about weight he is right it does get heavy after holding it awhile but if you are in decent shape and carry it around alot like I do in the woods where I live and can shoot in then its not a problem.When my Father was in Korea he humped around an M1 and hes not a huge guy but very strong even now in his 70s he can handle my HBAR carbine fine.as far as the gain in rapid fire or full auto and even sustained rapid fire is where the gain in reliability is just ask any soldier who had his M4 fail on full auto with the earlier lighter barrels.
Bradd_D
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Posted: 7/18/2004 8:42:07 PM

Originally Posted By model927:
as far as the gain in rapid fire or full auto and even sustained rapid fire is where the gain in reliability is just ask any soldier who had his M4 fail on full auto with the earlier lighter barrels.



We've been shooting A1's and A2's on full auto and sustained rapid fire for 40 years and reliability hasn't been an issue. Why would the M4 be any more prone to failure?
StormSurge
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Posted: 7/19/2004 12:57:24 AM
The failure of the M-4 barrel in the hands of certain Special Forces operators in field conditions is well known; check out the photos on pages 94 and 95 of Black Rifle II to see for yourself.

Granted, these catastophic failures were induced by using a light carbine in the role of a light machinegun; or are the traditional labels and weapons catagories now not as valid as they once were? In any case, no civilian shooter will probably be able to duplicate such failures. Especially if he is paing for the ammo!
chewbacca
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Posted: 7/19/2004 1:44:42 AM


Bushmaster Barrel Weights

Weight In Pounds, for milled front sight subtract 0.2 pounds



Barrel length_________Heavy Barrels________ Fluted Barrels

10"_________________2.0_________________1.9
11.5"_______________ 2.2_________________2.0
11.5/5.5"____________2.6_________________2.5
14.5"_______________ 2.5_________________2.2
14.5"AK_____________2.7_________________2.4
14.5"MY_____________2.7_________________2.4
14.5"AM (phantom)____2.7_________________2.4
16"_________________2.7_________________2.3
16" Dissipator________ 3.0_________________2.6
20"_________________3.5_________________3.0
24"_________________3.9_________________3.1
26"_________________4.0_________________3.2




Military Style Barrels

14.5"M4_____________2.0
14.5"M4AK__________ 2.2
14.5"M4MY__________ 2.2
14.5"M4AM (phantom)_ 2.2
16"M4 Dissipator______ 2.3
16" Superlight________ 1.9
16"M4______________ 2.2
20"A2 (govt profile)____2.5


1lb difference between A2 and Hbar...and this is Bushies Hbar; there is no standard Hbar profile. As I have stated many times before I prefer my 16" Hbar for one reason, and that is the forward weight keeps the weapon more stable when I am out of breath. Oh yah the forward weight also aids in faster splits. Don't get me wrong by thinking I don't like lite weights...I like them all!! It is just what ever floats your boat.

I am strong ( ) so honestly the 8oz difference between my Hbar and the 16" M4 doesn't mean shit. I can feel a difference but it is nothing to fret over.

But this is just me.


JTR8541
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Posted: 7/19/2004 4:42:53 AM
The reason I’m asking is that as soon as the ban goes away I’m planning on snapping an A2 upper onto one of my bushmaster lowers and I’ve also been thinking of doing an A4gery and setting an ACOG or ELCAN a la C7 onto the top of the rifle. With the A4gery I was wondering, do I go with the A2 profile or the HBAR. It’s really sounding like the A2 profile barrel is the way to go. Also, I called Bushmaster about this and they said that an A2 Government profile could be had in a complete upper and even in a 1/7 twist. This is great news and something I would like to see them continue selling, supporting that is probably a good idea.
Combat_Jack
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Posted: 7/19/2004 4:55:44 AM

Originally Posted By model927:
Lets not forget that the new M4 barrels on the SOCCOM M4A1 are HBARs and I dont hear those guys complaining about weight.The new M4 barrels are machined only in the 2 spots to attach the M203 wich makes the new M4 barrel about 3 or 4 ounces lighter than a civilian HBAR 14.5 so the weight is realy not a factor.Other M4s of course not used by soccom still have a lighter weight profile.As far as what TROY says about weight he is right it does get heavy after holding it awhile but if you are in decent shape and carry it around alot like I do in the woods where I live and can shoot in then its not a problem.When my Father was in Korea he humped around an M1 and hes not a huge guy but very strong even now in his 70s he can handle my HBAR carbine fine.as far as the gain in rapid fire or full auto and even sustained rapid fire is where the gain in reliability is just ask any soldier who had his M4 fail on full auto with the earlier lighter barrels.



M4A1 is only 4 ounces heavier than M4.
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