How much less longevity does one get out of stainless AR barrels compared to button broached barrels that are either chrome lined or nitrated?

I don't know how much more longevity 4150 barrels provide over 4140 barrels.

Assume only semi-auto shooting.

Stainless: Half as many rounds as regular steel barrels? Two thirds as many?

C/L and nitrided, 15-20k rounds.
Stainless 4-5k.
4140/4150 (uncoated) negligable difference.

Near enough the same.

https://www.ar15.com/forums/industry/My_18_month__15K_rounds_SS_barrel_range_report_/130-158390/

This.

Oh, and just so you know, broaching a barrel is different from button rifling.  Broaching is very similar to single point cut rifling, except the tool has multiple cutting points and all the rifling is cut on a single pass.  Button rifling does not remove metal but plastically deforms the material by pulling a carbide "button" through the bore.

Rifling broach:



Rifling button:

(Which you can buy on Amazon)

This is interesting. I would have guessed half for stainless compared to 4140/4150.

A stainless barrel will last a lot longer than 4-5k rounds. They will last that long as competition serviceable to 600 yards in NRA/CMP tournaments. After they won't shoot good 10/X-ring scores at 600, they can soldier on for at least another 5k rounds as a practice/varmint/beater rifle.

If anyone wants to ruin any barrel in short order, start doing mag dumps with it. Heat will ruin a barrel a lot quicker than neglect ever did.

What about nitrided SS?  Seem like the best of both worlds, assuming the barrel was good to go pre-treatment (as well as it could be for not being broken in).

Nitride will not last as long a a good chromium plated barrel . . .

I have a few of the uncoated 4140/4150 barrels and like them just fine when comparing to my Stainless barrels. The chrome lining is where the extra longevity really comes into play but at the expense of accuracy.

I will gladly take an unlined but 'quality' barrel over an 'elcheapo' but lined barrel any day of the week and be happy about it. :)

Left are obviously unlined / uncoated SS, far right is an unlined / uncoated of the 4140/4150 type steel and in the middle are chrome lined.




The cost of the barrels is trivial compared to the cost of the ammo required to kill them. Especially so if a guy is not just using them for a bullet hose and mag dumping them to death...

My buddy has his Bartlein barrels nitrided.  He says his 6.5BR barrels last significantly longer then plain stainless.
I haven't talked to him in a while, but last I did he said that stainless + nitride is the way to go.

Granted, this is a Bartlein barrel in a Kelby action, not an AR.