Nickle Boron barrel extension?

[Skeeter98]

Are these a good idea? There's a barrel from ballistic advantage i'm interested in and the barrels with the profile I want have Nickle boron coated barrel extensions and feed ramps. These are coated by Failzero if that means anything. My question is doesn't NiB have a tendency to chip? And since the locking lugs are such a critical area, wouldn't a chipped NiB coating throw the locking lugs out of spec? Also doesn't this coating eventually wear off? To coat things that have specific tolerances, there has to be slightly less material to account for the coating thickness. The benefits of an NiB barrel extension is the added lubricity of feed and bolt operation which would help to prevent malfunctions and I think, potentially, better fitment to the receiver.

[dentron]

I have 4 BA barrels, 2 have NIB extensions, 1 has over 5k rounds on it (many suppressed). No problems at all. No chipping, no tolerance issues when assembling. I recommend their hanson barrels with confidence.

[markm]

Isn't NiB the stuff that was on my cracked bolt? Geeze... I've forgotten a lot about the AR over the last few years.

My issues with NiB were that:

1. It was a carbon fouling magnet. My bolt looked black all the time because fouling stuck to it like a magnet, and...

2. Whomever coated by bolt did it wrong and brittled it so that it failed. One lug fell off, then another soon after. I sent it to a member here for destructive analysis.

Bottom line... I'd NEVER buy anything NiB for the AR15 based on the bad surface texture that grabs onto fouling and won't let go.

[MegademiC]

Isn't NiB the stuff that was on my cracked bolt? Geeze... I've forgotten a lot about the AR over the last few years.

My issues with NiB were that:

1. It was a carbon fouling magnet. My bolt looked black all the time because fouling stuck to it like a magnet, and...

2. Whomever coated by bolt did it wrong and brittled it so that it failed. One lug fell off, then another soon after. I sent it to a member here for destructive analysis.

Bottom line... I'd NEVER buy anything NiB for the AR15 based on the bad surface texture that grabs onto fouling and won't let go.

That was me, and yes it was.

The NiB coating morphology is like grass, not a coat of paint, and carbon settles in there. It only turned silver after some of the coating was removed chemically (agressive solvents for extended perionds did nothing visually. You had other lugs that were cracked as well, and there were many cracks seen in the microscope photos. It looked like it was propegating from the coating into the substrate.

My main concern would be excessive wear of the lug faces since NiB is so hard, unless you paired it with a NP3 bolt. I dont know if it would have any practical effect though. On the otherhand, i doubt you would see benefits from a NiB ext either.

[Skeeter98]

That was me, and yes it was.

The NiB coating morphology is like grass, not a coat of paint, and carbon settles in there. It only turned silver after some of the coating was removed chemically (agressive solvents for extended perionds did nothing visually. You had other lugs that were cracked as well, and there were many cracks seen in the microscope photos. It looked like it was propegating from the coating into the substrate.

My main concern would be excessive wear of the lug faces since NiB is so hard, unless you paired it with a NP3 bolt. I dont know if it would have any practical effect though. On the otherhand, i doubt you would see benefits from a NiB ext either.

That's what I was thinking. I wanted a nitride bolt and didn't realize that the interior of the lugs were also NiB. I was thinking the same thing with paring the barrel with a NiB bolt to prevent uneven wear.

[markm]

That was me, and yes it was.

My brain lost touch with M4C and carbine knowledge after my divorce. I swear... we even forgot about carbine buffers when we were trouble shooting a gun a few weeks back.

[Skeeter98]

I'll probably use a Rainier arms NiB BCG over the Nitride one once they are back in stock.

[MegademiC]

I'll probably use a Rainier arms NiB BCG over the Nitride one once they are back in stock.

Good luck. Id pick NP3 over NiB if it was me.

[Skeeter98]

Good luck. Id pick NP3 over NiB if it was me.

Why? NiB is harder and slicker. Is it better to have a hard surface against a hard surface or a hard surface against a softer one? It's not rhetorical. I'm new to coatings, metals and AR technology.

[MegademiC]

Why? NiB is harder and slicker. Is it better to have a hard surface against a hard surface or a hard surface against a softer one? It's not rhetorical. I'm new to coatings, metals and AR technology.

You’re right, i thought NP3 was harder. There was a study and the wear properties of NiB was not very good when paired with itself. Bare steel was better.

See page 42 of pdf.

http://www.arl.army.mil/arlreports/2013/ARL-CR-713.pdf


I would expect better results from NP3 due to morphology, ptfe, and honestly, the lower hardness might help as it wouldnt be as brittle. Just an educated guess.