AR barrels made of 416R stainless.....how do they compare?

[ABNAK]

Compare to chrome lined or nitrided (melonited) as far as durability and corrosion resistance? Does a barrel of 416R hold up to wear and corrosion better than a non-lined, 4150V for instance? I realize that the entire barrel is made of stainless but I'm speaking specifically about chamber and bore related issues of wear and corrosion.

I've always heard that stainless is "softer" than other barrel materials, and I know for a fact (having seen it myself on a pistol slide) that stainless can rust.

[mdram]

http://faxonfirearms.com/blog/4150-carbon-steel-vs-416r-stainless-which-is-right-for-me/

[MegademiC]

Compare to chrome lined or nitrided (melonited) as far as durability and corrosion resistance? Does a barrel of 416R hold up to wear and corrosion better than a non-lined, 4150V for instance? I realize that the entire barrel is made of stainless but I'm speaking specifically about chamber and bore related issues of wear and corrosion.

I've always heard that stainless is "softer" than other barrel materials, and I know for a fact (having seen it myself on a pistol slide) that stainless can rust.

Somewhat a loaded question. All stainless can rust. Some is harder than others, some is more corrossion resistant.

For throat erosion, you should be more concerned with melting temp and other attributes, not corrosion resistance (salt spray test). Meloniting ss (iirc) increases life of the barrel, but lowers corrosion resistance.

[VIP3R 237]

This is the best write up I've seen about 416 steel barrels.

https://www.quora.com/Which-material-is-used-to-manufacturing-of-rifle-barrel-and-why

Here is another take on 416 as a barrel steel.

http://www.schuemann.com/Portals/0/Documentation/Webfile_Barrel_Steel.pdf

[ABNAK]

Somewhat a loaded question. All stainless can rust. Some is harder than others, some is more corrossion resistant.

For throat erosion, you should be more concerned with melting temp and other attributes, not corrosion resistance (salt spray test). Meloniting ss (iirc) increases life of the barrel, but lowers corrosion resistance.

I thought Meloniting/nitriding increased corrosion resistance? Or is this something specific to how it affects stainless steel in particular?

[vicious_cb]

Nitriding increases corrosion resistance in 400 series stainless steels since they aren't very corrosion resistant in the first place. I left a stainless steel barrel in a cold trunk overnight and the condensation caused rust spots on my barrel.

Nitriding something like 17-4 stainless would actually decrease corrosion resistance.

[MistWolf]

Stainless steel, like aluminum, forms a corrosion resistant surface by oxidizing. If cut off from the oxygen in the air, it cannot renew the oxide surface. Nitriding and other similar treatments seals the surface and cuts it off from the oxygen, thus reducing the ability of the stainless steel to oxide and protect itself from corrosion

[ABNAK]

Stainless steel, like aluminum, forms a corrosion resistant surface by oxidizing. If cut off from the oxygen in the air, it cannot renew the oxide surface. Nitriding and other similar treatments seals the surface and cuts it off from the oxygen, thus reducing the ability of the stainless steel to oxide and protect itself from corrosion

Interesting. So something like nitriding, which is an enhancement to corrosion resistance with most other barrel steels, can be counter-productive in that category with stainless (or some stainless). Did not know that. That's why M4C is a wealth of knowledge! Thanks for the info.

[MQ105]

Are not most SS AR barrels 410 or 416/416R, and therefore would benefit from nitriding (for corrosion purposes)?

[MegademiC]

Are not most SS AR barrels 410 or 416/416R, and therefore would benefit from nitriding (for corrosion purposes)?

You will have to elaborate on why 416 may benefit.

It's 12-14 % cr which puts it in the "not sure" category for me.

Op, stainless is softer, but tougher than other steels. SS holds up better than a non lined barrel in (iirc) every category, but not as well as Cr lined.