Looking at, for instance, PSA's FN barrels, I have been curious if anyone can explain a few things to me.

If a barrel is chrome lined, how can the benefits of CHFing (if there are, in fact, any) apply to resisting wear that isn't applied to it? Once the chromes gone, so is the barrel. Which brings me to my next question, should not the barrel be through once the first layer thickness of chrome is missing ? How could the chrome going deeper be of any use? Can there really be any benefit to CHF+dbl Chrome over a standard barrel such as the PSA premium non-CHF FN barrels?

I am not being facetious, I am curious if there's actually a reason why it makes sense. Thanks everyone in advance.

From my understanding(VERY limited, take with grain of salt) the chrome sticks to the barrel better. I don't know that a thicker chrome lining does anything...really. When chrome wears down it can chip which would be a worse harm to the gun if it was thicker. Perhaps the thickness keeps it from chipping as easily.

Now, onto the "how is it better, ect."

Well, the proponents of CHF say the gun is more accurate because it has less flex and malformation when extreme heat is applied. IE: fully auto fire theoretically holds point of impact better on a CHF barrel. This same resilience can theoretically account for longer barrel life.

You are shooting on chrome either way, so accuracy is and always will be barrel to barrel, button or chf, imho. However, accuracy is also measured by how well a barrel holds point of impact so if there is truth to the heat theory then the barrels could technically be "more accurate" under certain high stress conditions.

That said, there aren't a lot of studies or facts on the actual benefits of CHF over button rifling or vice versa. There are however, many anecdotal and marketing materials as well as facts about how said processes are done. Perhaps a metallurgist can chime in.

Edited: Read the post below mine

Here is the scoop.  I had some questions myself so I called into FN a year ago and spoke with one of their tech guys.

A couple of things here.  

The M249 blanks are CHF, but it is their proprietary blend of steel that gives the barrel the majority of their extended life.  These barrels do NOT use the same steel that is in the mil spec M4 barrels, rather they use some secret blend, proprietary to FN.  The CHF process helps extend barrel life a little bit, but he said it's the blend of steel they use in the M249 barrels that makes the most difference.

He also said that it isn't double chrome lined per say, they use a different type of chrome that ends up plating thicker than the mil spec M4 standard chrome.  

For what it's worth, that's what he told me!


Oh, and I asked about melonite / salt bath nitriding, etc.  He said that that process might help some of the inferior grades of steels.  They've conducted tests on their M249 steel blend and said it actually negatively effected the properties!  Go figure!

Sounds legit. I'm gonna change my answer to this. Quality barrel manufacturers > crappy barrel manufacturers, irregardless of the process.

haha, that does sound legit, Probably worth any price jump just for piece of mind huh? not to mention, if it is good enough for the saw....what isn't it good for? lol

Here were my assumptions, chrome wearing is different than chrome wearing off another material, less pliable steel will move less and therefore have less tension built against the chrome(which I understand is harder and less flexible than the steel), I am no scientist (as I am sure you can tell) so please if anyone else cares to chime in with more details and maybe some science.

Thanks for the answers so far guys!

Now, if we can just get the military to change the spec sheet or even just FN's commercial sector to make M4 barrels from the M249 SAW bbl's proprietary alloy elements, we would have some long lasting barrels! I'm sure there's a downside besides the fact it's not mil-spec for the M4 or A4, but still, I want one.

I would buy in to FNs that salt and nitride hurt their  barrels. It's cheap for a reason. With that said I have a few nitride barrels and I love them. For the money and I have put a few thousand rounds down range with a out lost in accuracy.  They are hard to beat for price.