XM16E1 barrel erosion study (1966)

[26 Inf]

Great info, learned things.

[vicious_cb]

Obviously the solution is explosive cladding. Because explosions are cool.

[MegademiC]

Obviously the solution is explosive cladding. Because explosions are cool.

With what?
The coating has to be thin enough to clad and still offer benefits. Thin coatings do little for erosion from what Ive seen.

[JoshNC]

Show me one military on this planet that uses a nitride barrel on their issue weapon. Nitride is a cheapskate shortcut that is popular with manufacturers now because it's, well, a cheaper way of doing it. I would take a nitride barrel over a non-treated one but NEVER over a properly hard chromed one. YMMV.

Switzerland.

[Sry0fcr]

Stellite lining actually has a lot of drawbacks.

1) Instead of one hunk of steel with a precision round hole that is perfectly straight, you need at least three parts, usually four, parts with not only straight precision holes in them, the outside has to be held to excruciating tight tolerances.

2) The liner is normally only a third the length of the rifled bore, so there is a discontinuity in the rifling. As much as 0.010".

3) Because the chamber, throat and barrel are three different parts, good luck keeping all the bores perfectly concentric. You can see that in the drawing that they weren't expecting better than 0.010" T.I.R. chamber to throat and 0.001" T.I.R. throat to bore.

There is a reason the military has drifted away from Stellite lining, in favor of the much simpler and cheaper chromium plating. The cost of making a built-up, stellite lined barrel, far exceeds the cost of the two or two-and-a-half chrome-plated barrels for the same life.

Perfect example of something being great in theory that didn't work out in real life. Also, I'd caution against applying lessons learned from 25/30mm chain guns to 5.56 small arms. It's a data point to be sure but may not be relevant.

[ABNAK]

Switzerland.

Okay, what weapon?

[georgeib]

Pretty sure all the Swiss Sig 55x rifle barrels are nitrocarburized. All of mine have been.

[lysander]

With what?
The coating has to be thin enough to clad and still offer benefits. Thin coatings do little for erosion from what Ive seen.

Tantalum alloy

[AndyLate]

Show me one military on this planet that uses a nitride barrel on their issue weapon. Nitride is a cheapskate shortcut that is popular with manufacturers now because it's, well, a cheaper way of doing it. I would take a nitride barrel over a non-treated one but NEVER over a properly hard chromed one. YMMV.

Every military that issues a Glock.

[Slater]

PSA has this description of their "Premium" carbine barrel:

"Barrel: A proprietary blend of Hammer forged chrome molly vanadium made by FN that is referred to as "Machine Gun Steel" by virtue of its required use in FN's M249 and M240 weapons. The hammer forging process work hardens the steel, making it more durable. In addition, the chrome process for the bore allows for a lining almost twice as thick as a standard M16 for enhanced durability."

Does the double thick chrome lining have any effect on accuracy?