Drmark said:
https://youtu.be/Yfs1Czm8iiE
Thanks Drmark... very useful video!
campinginaz said:
I didn't know there were this many coatings! What do you guys like best? I have nitride and phosphate but was looking into nickel boron.
https://www.recoilweb.com/best-ar-15-bolt-carrier-groups-176713.html
My kid is a bit of a tech and research nerd, and when he built his second AR and was building with what his research told him was the best value / high quality parts (so not "the most expensive high-zoot race stuff - but the stuff that he found to be "very high quality and highly reliable") he chose a Sharps Rifle nickle boron coated BCG. The guy in the video that DrMark posted does not like nickle boron - but others do - and it sounds like the guy's objections are more around the thickness of the coating as opposed to how it functions as a "slick" protective coating.
I also tend to over-think things - so... my view regarding the "what is my favorite" is that... "it depends." My "favorite" will change based on the purpose of the rifle and associated with that, the cost of the item relative to its purpose is a big chunk of what should be considered "the best" unit for purpose.
I tend to divide the question into two families... plinking guns, duty / competition guns...
Plinking guns - if you are building a plinking rifle that will get taken out to blast cans a few weekends per year - I'd buy a very basic / inexpensive BCG from a reputable source that will warranty it if there is a manufacturing defect that makes it fail to function when you take it out the first time. If it works when you buy it (and it probably will) you win... The $79.99 nitrided BCG from PSA, if it works when you shoot it the first time and clean / lube it every once in a while will very likely give you decades of "shoot a couple hundred rounds on a Saturday a few times per year") - and you can buy a few of them for the price of a very high end BCG. The $160 that you save by buying a basic BCG can be turned into two more BCGs for other plinking guns - or maybe a bunch of rounds or reloading materials.
Competition and Duty guns - If you are a building a gun for competition or duty and are going to shoot
a LOT - like thousands of rounds per week then durability is key - as well as reliability as a function of durability. In this case - I'd probably buy either a chromed or DLC coated BCG. That said - I'm speaking here mostly as a keyboard warrior (I only own one chromed BCG and I don't own a DLC plated BCG but I think my next gun is getting one).
Again - for a duty / competition gun, before worrying about coatings, I'd put emphasis on the quality of machining and the base materials that they are made from first - then worry about the coating.
My 2 cents...