What's the consensus on carbon fiber barrels?

[gaucho1]

worrying about the effect of aerodynamics on the acceleration of a minivan. This is GOOD!

[JediGuy]

But if your minivan has AWD, decent aerodynamics, and a good engine, it can still get moving faster than an average sedan.

Just saying. I like our Sienna.

[DG23]

From a cold bore, any profiles turned from the same blanks firing the same ammunition will shoot just about the same, but a lighter profile will start to wander within about five shots, whereas a thicker profile might take 20 shots before it gets hot enough to start expanding. The difference between a heavy and light profile AR barrel isn't really relevant to the platform or the way its used, from a rigidity perspective. The whole platform has all kinds of other issues. It's not a precision rifle.

Will bet that you do not own and have never owned an AR15 with a bull barrel. Not even one...



20 rounds my ass.

[lysander]

You have a barrel slopped into an aluminum receiver and a bolt that doesn't stay square to the chamber when the cartridge is pressurized.

The bolt is not held square to the chamber? FALSE

The locking faces of the lugs on the extension, and the front face are held square to the threads.

The bore of the barrel is held square to the thread buttress.

So, when the barrel extension is threaded on to the barrel the locking faces of the lugs are square the bore and chamber axis.

The rear faces of the bolt's locking lugs are held square to the breech face.

The breech face is perpendicular to the chamber and bore to within 0.0005".

Also, the upper is square enough to the barrel, per print, and the carrier has enough clearance, to keep allow the bolt to go square to the barrel without interference from the upper.

Worrying about rigidity in an AR barrel at the expense of thermal mass and heat dissipation is like worrying about the effect of aerodynamics on the acceleration of a minivan.

So, explain fluted barrels, that have been used from the very beginnings of the AR-10/AR-15? If it were only about soaking up heat in a massive body, flutes would be pointless.

Or, the USMC specifically requesting the M16A2 have the "HBAR" barrel, due to its better rigidity.

[titsonritz]

Any barrel will string when it gets hot enough to expand. As I said several times, thicker barrels take a lot longer to heat up, and they dissipate heat faster into the air due to having more surface area. A bull barrel has roughly twice the surface area as a pencil and roughly three times the mass.

From a cold bore, any profiles turned from the same blanks firing the same ammunition will shoot just about the same, but a lighter profile will start to wander within about five shots, whereas a thicker profile might take 20 shots before it gets hot enough to start expanding. The difference between a heavy and light profile AR barrel isn't really relevant to the platform or the way its used, from a rigidity perspective. The whole platform has all kinds of other issues. It's not a precision rifle. You have a barrel slopped into an aluminum receiver and a bolt that doesn't stay square to the chamber when the cartridge is pressurized. Worrying about rigidity in an AR barrel at the expense of thermal mass and heat dissipation is like worrying about the effect of aerodynamics on the acceleration of a minivan.

So which is the very bestest for innagrass shooting?

[1168]

An AR can absolutely be a precision rifle. Do you read Molon’s posts?

[GTF425]

So which is the very bestest for innagrass shooting?

The one with iron sights.

[titsonritz]

The one with iron sights.

Oh man, you got me.

[okie]

The bolt is not held square to the chamber? FALSE

The locking faces of the lugs on the extension, and the front face are held square to the threads.

The bore of the barrel is held square to the thread buttress.

So, when the barrel extension is threaded on to the barrel the locking faces of the lugs are square the bore and chamber axis.

The rear faces of the bolt's locking lugs are held square to the breech face.

The breech face is perpendicular to the chamber and bore to within 0.0005".

Also, the upper is square enough to the barrel, per print, and the carrier has enough clearance, to keep allow the bolt to go square to the barrel without interference from the upper.


So, explain fluted barrels, that have been used from the very beginnings of the AR-10/AR-15? If it were only about soaking up heat in a massive body, flutes would be pointless.

Or, the USMC specifically requesting the M16A2 have the "HBAR" barrel, due to its better rigidity.

Flutes theoretically increase surface area and dissipate heat faster. The AR's bolt tilts slightly when under pressure. The military says and does stupid stuff all the time. They also thought the M16A1's barrels were bending so...

But we're getting way off track here. What I want to know specifically is if there's some magic in the carbon composites used with barrels that enables them to conduct heat, or if it's as I suspect and they're just insulating the barrel and making the whole situation worse.

[gaucho1]

Does carbon fiber wrap resist bending caused by heat better than barrel steel? If so, is it a lighter method of keeping the barrel straight?