Just read all the responses and I'm more confused now. The 11511 is slightly better in durability because of all the chrome that's added?
It's milspec in trigger guard but some save it's weaker design?
Both guns have none milspec 4140 barrel (milspec is 5150?)
Milspec is 4150, but part of that specification is also magnetic particle testing, etc. There's more to the spec than just the material.
Chrome plating helps protect the bore from corrosion and erosion. It provides a hard surface for the bullet to pass over and protects the steel from that wear, extending barrel life. The drawback is any imperfections in the barrel's bore will not be smoothed out from firing, and are simply coated with chrome. As a generality your best accuracy barrels are not chrome lined. (I want to emphasize "generality". There have definitely been exceptions.)
Melonite treatment, which S&W calls Armornite, is an alternative barrel treatment. Instead of layering on the surface like chrome, it goes into the metal surface. Supposedly this does not have the drawbacks of coating imperfections, but I have not heard of a study saying those imperfections tend to smooth out in a reasonable round count either. Claims have been made it is superior to chrome and barrels last longer. I prefer it to chrome because the as-cut barrel dimensions are kept, not changed by coating.
Is a chrome or Melonite treated 4140 barrel as good as a 4150 barrel? Technically, no. But the longevity of both barrels is increased to the point where it is not likely the average owner is going to wear either out unless they have a big ammo budget or are shooting so fast and often that the barrel becomes an honorary branding iron.
For maximum accuracy I prefer an untreated barrel made from premium steel, but that AR has a low round count as it is reserved for hunting.
As for the trigger guard, the swing down milspec design is generally thought to be weaker than an integral guard because it is possible for a blow to that area to break an ear off. Now, you have to ask yourself this.... Have you ever personally known anyone who broke an ear off? I've never even seen a pic on the internet of a broken ear. I think that argument is a moot point. So for "authenticity" of a "milspec" gun you want the ears. But that means you want the rest of the gun to be milspec too, so watch for barrel material, magnetic particle checking, etc. The reason I like the integral guard is I don't have to buy an aftermarket guard for winter gloves and fit it. Funny how an integral guard used to be a selling point on high end ARs and now it is offered on some budget guns.
