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View Full Version : Barrel profiles: Government vs Medium contour


connorr93
06-01-2012, 8:13 AM
So Im in the process of building my first AR and I am trying to decide on a contour. I want something that will stay accurate after numerous mag dumps. I am also trying to keep this as light as possible. My question is will the government profile be able to stay accurate after extensive sustained fire. I know the military uses it on their full auto guns so I think it can do the job I just want to be sure. What do you guys use and how does it work for you? What is the most popular in a AR platform Government profile or medium contour?

smittty
06-01-2012, 8:42 AM
Which ever costs less?

BucDan
06-01-2012, 8:59 AM
Mid length govt profile is best. Some companies are using a slightly smaller OD contour like KAC and PSA

TwinStick
06-01-2012, 9:13 AM
Funny, this is something I never would have thought about when I built my first AR. Honestly, I don't think I'd care much now, but good for you for trying to get exactly what you'll be happy with. I say get the Gov profile, then get another AR shortly thereafter for a different purpose.

phamkl
06-01-2012, 10:49 AM
I believe the gov't profile has the grenade launcher cut so there's no reason at all for most of us to go with gov't over medium contour.

connorr93
06-01-2012, 5:39 PM
So the government contour would work for my needs then?

xpbprox
06-01-2012, 5:50 PM
Either one, just don't cheap out on barrels.

ExtremeX
06-01-2012, 5:59 PM
I have 3 16" barrels in M4 Gov, Medium/Standard, and Recce profiles.

I prefer medium over the M4 Gov, and like my Recce profile the best since it cuts down on weight a little.

Keep in mind not all barrel manufactures profiles match up... The I had option of buying a medium that was about .750 across most of the barrel. The medium I picked up is .88, .75 gas block, and .73 muzzle end.

connorr93
06-01-2012, 6:04 PM
I have 3 16" barrels in M4 Gov, Medium/Standard, and Recce profiles.

I prefer medium over the M4 Gov, and like my Recce profile the best since it cuts down on weight a little.

Keep in mind not all barrel manufactures profiles match up... The I had option of buying a medium that was about .750 across most of the barrel. The medium I picked up is .88, .75 gas block, and .73 muzzle end.

Why is it that you perfer the medium profile over the government one?

ExtremeX
06-01-2012, 6:06 PM
I know the military uses it on their full auto guns so ... What is the most popular in a AR platform Government profile or medium contour?

There are different type of Gov profiles.

Most semi auto ar-15s for sale would use the 16" M4...

The M4A1 is a heavier version of that... its better for their full auto guns...

Heres a link.
http://www.ar15barrels.com/prod/govt.shtml

http://www.ar15barrels.com/profiles.shtml

ExtremeX
06-01-2012, 6:17 PM
Why is it that you perfer the medium profile over the government one?

Well for starters I don't think anyone is going to give me a m203 grenade launcher to mount to it... I don't need that notch cut-out in it, but I think it looks cool...

I just prefer heavier contours in my barrels. It better matches the type of shooting I do. I have a preference towards stainless barrels in heavier contours... My M4 profile is steel / chrome lined.

End of the day its part personal preference and part application. The profile is also secondary to finding a quality barrel from a reputable manufacture. Its pretty much the most important component in the rifle from a performance standpoint. So buy a good one and do your research.

nrakid88
06-01-2012, 6:40 PM
Check out the 16 inch stainless i have for sell. bravo company. thicker profile. accurate as HELL.

ExtremeX
06-01-2012, 7:32 PM
Check out the 16 inch stainless i have for sell. bravo company. thicker profile. accurate as HELL.

I want something that will stay accurate after numerous mag dumps. I am also trying to keep this as light as possible.

I'm going to venture to say a stainless barrel probably isn't for the OP. If that truly is his shooting style, hes probably going to be better off with a chrome lined or cold hammer forged barrel in a heavier profile.

I'm curious OP: What is your reasonable expectation of accuracy? Hitting a man sized target or sub moa groups?

I don't feel like typing and essay right now so ill give you some bullet points. Assuming the barrels are made to the same standard in manufacturing.

Light weight profiles + mag dump isn't going to give you sustained accuracy. Groups tend to open up as lighter profiled barrels heat up.

Typically a stainless barrel is more accurate. The downside is that it comes at a cost... barrel life

Stainless is said to be higher maintenance than CHF or CL.

CHF and CL barrels typically last longer, but wont deliver the type of accuracy as stainless.

Regardless of the barrel material, a heavier profile barrel will maintain better accuracy as it heats up.

connorr93
06-01-2012, 7:36 PM
I know how barrel types effect the bullet and barrel use. My question is simple. Will a government profile barrel stand up to my shooting with ought loosing accuracy?

ExtremeX
06-01-2012, 8:30 PM
:facepalm: sigh... you give very little information and expect solid answers.

All barrels will loose accuracy as they heat up, they will wear faster as they heat up. Barrel life and accuracy deteriorate with more abuse. It just depends on how much and is different across barrels. Its even different across the SAME Gov.. profile from different manufactures. Ur chrome lining might go to ****, I don't know. Not everything is built to the same standard!

We don't know what ur shooting at, how ur shooting, or how much ur shooting. If you can afford to shoot out the barrel you can probably afford to buy another one if it doesn't work out.

ill say it again...it depends on your expectation or definition of accuracy...

Its a subjective question with real no answer. If you just want someone to say sure why not so you can buy a barrel, then go for it.

Dhena81
06-01-2012, 9:21 PM
I'm building a rifle around a Noveske CHF barrel and a colt BCG its a CHF improved contour but the same weight as an M4 barrel. It's made of M249 machine gun steel and is double chrome lined with a pinned low profile gas block. John Noveske claims his CL barrels are as consistent as some SS barrels accuracy is good durability is excellent.

FX-05 Xiuhcoatl
06-01-2012, 10:14 PM
Government Profile barrel contour

nrakid88
06-02-2012, 11:12 AM
http://www.calguns.net/calgunforum/showthread.php?t=577569

This is the upper I have for sale. From what I have read, from people who shoot the hell out of there guns, good stainless steel is as good as chrome lined barrels. The accuracy dies at a slightly faster rate, but they are much more accurate to begin with, giving you a similar if not better barrel life. Case and point is in this thread, full auto with stainless barrel http://www.ar15.com/forums/t_2_130/158390_.html

Moonshine
06-02-2012, 12:45 PM
I just use an M4 profile on my rifle. Looks cool and palmetto armor has unbeatable prices on m4 uppers and barrels that are excellent quality. Most prefer mid length for a 16" though because the carbine gas system on the m4 profile was designed for a 14.5" barrel and the extra 1.5" can lead to additional recoil and some say lower barrel life.

nick
06-02-2012, 1:04 PM
I'm going to venture to say a stainless barrel probably isn't for the OP. If that truly is his shooting style, hes probably going to be better off with a chrome lined or cold hammer forged barrel in a heavier profile.

I'm curious OP: What is your reasonable expectation of accuracy? Hitting a man sized target or sub moa groups?

I don't feel like typing and essay right now so ill give you some bullet points. Assuming the barrels are made to the same standard in manufacturing.

Light weight profiles + mag dump isn't going to give you sustained accuracy. Groups tend to open up as lighter profiled barrels heat up.

Typically a stainless barrel is more accurate. The downside is that it comes at a cost... barrel life

Stainless is said to be higher maintenance than CHF or CL.

CHF and CL barrels typically last longer, but wont deliver the type of accuracy as stainless.

Regardless of the barrel material, a heavier profile barrel will maintain better accuracy as it heats up.

A stainless barrel can be nitrided, thus increasing its life. In fact, nitriding stainless steel will yield higher surface hardness than carbon steel.

shark92651
06-02-2012, 1:09 PM
I know how barrel types effect the bullet and barrel use. My question is simple. Will a government profile barrel stand up to my shooting with ought loosing accuracy?

I think you are over thinking this buying decision. Are you a match shooter, an operator, or a plinker? I would dare to say that a gov't profile AR barrel would fit the needs of 90% of the shooters out there. That is a totally unscientific assessment, however ;)

connorr93
06-02-2012, 1:21 PM
Ok thanks to everyone who helped! And yes I do way over think things. I am a perfectionist so naturally it takes me a long time to decide on stuff. :p

klewan
06-03-2012, 11:44 AM
I saw an article about dumping 1K rounds as fast possible thru a govt barrel. Barrel sagged an a round came out thru the top of the sag. Set the hand guard on fire, it was that hot. They added 5oz of steel to the govt barrel and repeated the test. Barrel got to 1K rounds without it sagging, the gastube overheated and failed this time. A little bit of metal seems to help a lot if you've got ammo to burn.

ANG Tactical
06-03-2012, 12:02 PM
Well for starters I don't think anyone is going to give me a m203 grenade launcher to mount to it... I don't need that notch cut-out in it, but I think it looks cool...

I just prefer heavier contours in my barrels. It better matches the type of shooting I do. I have a preference towards stainless barrels in heavier contours... My M4 profile is steel / chrome lined.

End of the day its part personal preference and part application. The profile is also secondary to finding a quality barrel from a reputable manufacture. Its pretty much the most important component in the rifle from a performance standpoint. So buy a good one and do your research.

I agree. I have a heavy contour on mine. As long as it's a good barrel you shouldn't have problems. Like what was said above, don't skimp on the barrel.

ExtremeX
06-03-2012, 12:36 PM
I saw an article about dumping 1K rounds as fast possible thru a govt barrel. Barrel sagged an a round came out thru the top of the sag. Set the hand guard on fire, it was that hot. They added 5oz of steel to the govt barrel and repeated the test. Barrel got to 1K rounds without it sagging, the gastube overheated and failed this time. A little bit of metal seems to help a lot if you've got ammo to burn.

If you ever find the article send it over to me, id like to check it out.

If you are going to run a gun this hard, it would also be wise to run a free float hand guard, it would help prevent any additional stress on the barrel causing sagging or warping from things like vertical grips.

It probably wouldn't hurt to get a heavy barrel and get some fluting to reduce weight and increase surface area for cooling too.