Dark rifle barrel?

[chuck]

I bought a used 742 Remington and the barrel was filthy, took a lot of time but got it clean. but it is dark can any one tell me why?

 

[JFB]

My guess would be Iron (II)oxide – Fe3O4, ie "black rust". this is sort of like blueing that devolps when the exposure to air (oxygen) is limited, possibly by the fouling. assuming the fouling was mainly carbon from burnt powder, there probably is some surface harden by absorbtion too besides the harden from the black rust film

 

[Mobuck]

Surplus rifles that had fired corrosive ammo will show up with "dark bores". What caliber is the 742?
If it's 30/06, someone may have fired some corrosive ammo through and didn't get it cleaned properly.
FWIW, as long as there's no pitting, the bore will still provide good service and accuracy. I have a couple of M98 in 8mm. One has a pristine shiny bore and the other is darkish but both are equally accurate.

 

[Salmoneye]

Just remember that the 742 is not a range toy...

If you fire a few boxes a year, it will last a lifetime, but if you want to shoot a lot, you will sooner or later pummel the internal rails enough to start causing jams...

The rails can then be 'cleaned up' once, maybe twice, before the entire receiver is toast...

 

[Rick Courtright]

Just remember that the 742 is not a range toy...

If you fire a few boxes a year, it will last a lifetime, but if you want to shoot a lot, you will sooner or later pummel the internal rails enough to start causing jams...

The rails can then be 'cleaned up' once, maybe twice, before the entire receiver is toast...

Hi,

Is the 742 the one they made with both steel and aluminum receivers? A buddy has whatever model that was, in steel. I understand the steel ones weren't quite the problem children the aluminum ones were.

Rick C

 

[chuck]

Thanks to all of you Chuck

 

[Salmoneye]

Just remember that the 742 is not a range toy...

If you fire a few boxes a year, it will last a lifetime, but if you want to shoot a lot, you will sooner or later pummel the internal rails enough to start causing jams...

The rails can then be 'cleaned up' once, maybe twice, before the entire receiver is toast...

Hi,

Is the 742 the one they made with both steel and aluminum receivers? A buddy has whatever model that was, in steel. I understand the steel ones weren't quite the problem children the aluminum ones were.

Rick C

No aluminum, just a design that rotates the bolt while recoiling, and insufficient meat in the rails...It gouged the rails which were a softer steel than the bolt...

Allegedly this was all sussed out by the time they changed to the model 7400...

I have a 7400 carbine in .30-06, and the inside rear of the receiver shows none of the wear that my Father's 742 did...

I gifted that 742 to one of my Brothers In Law, and he still shoots it, but sparingly...