Bolt carriers, Chrome lined or Nitride

[vaguru]

I have been looking at bolt carriers lately and notice that chrome lined bores and gas keys are few and far between. Most now I find are Black Nitride.

How does this affect the usage of the carrier?

From what I can tell it's basically an easier to clean option with the chrome in very harsh conditions.

For the average guy shooting competition, hunting or plinking, is there any disadvantage to the Black Nitride carrier?

[grayfox]

This is only IMO on this of course.
I don't see the average guy shooting so hard that a chrome lining is necessary.
Get a good quality nitrided or a good quality nickel-boron and go shoot.
Now for rough or extreme conditions, or if you're doing sub-zero or "wartime" mag dumps... could be a different story, but I don't go there myself.

Having said this, and also as an IMO, I don't trust toolcraft bcg's even though they are plentiful.

From a metallurgy standpoint, I think the nitrided treatment, or salt bath nitride, if done by a reputable mfr, hardens and slickens the surface about the best. Sometimes the NiB's I've found are a bit easier to clean and "seem" "slippery-er", but from my shooting I've yet to wear out any of my bcgs. Broke a bolt tooth couple times, but no other failures in bcg components that I can recall. Both Nitrided and NiB's.

There are premium mfrs who charge a premium too, and could be worth it, but bcg mfg is becoming more of a commodity item, with the caveat of staying with good vendors and still evaluating for quality. Replace-ability is key for me as time-between-failiures for me has been pretty long. I keep 1 or 2 spares on hand.

Others will have differing opinions on this, but this is what I think.

[A5Blaster Number 2]

Unless your under combat fireing schedules, you will never notice a difference in the two.

Last few years I have settled on rtb nib lowmass coated bcg's, simple because they look cool and clean up easier then BN bcg's and because I run adjustable gas.

[montana]

Depends on the manufacturer. If the manufacturer doesn't adjust the difference between the chrome and nitride size difference during manufacturing, then the carrier could be less gas efficient during the nitride process. There are other areas besides the coating that should be checked out before using. The carrier is the heart of the AR platform and like the barrel can make all the difference. The 3 bore, machining quality, length, gas key, etc..
Coatings can make a difference, https://www.youtube.com/watch?v=Yfs1Czm8iiE

[LRRPF52]

It’s hard to beat the surface hardness and durability of the hard-chromed carrier bore and gas key.

[Double Naught Spy]

I have several standard parkerized and one black nitrided. I don't notice a difference in operation between them. I don't think you would be likely to notice anything between chromed and nitrided. It probably matters, but not enough to matter in the grand scheme.

For a logic comparison from when I used to shoot a lot of pistol ammo, there were always discussions on what ammo was the cleanest to shoot. Brand B was cleaner than brand A but brand C had them both beat. Sure enough, you to 10 rounds down the barrel and compare between the three and there was a noticeable difference. Somewhere after 150 rounds to maybe 200 rounds, nobody could tell the difference. So the cleaner ammo only really mattered if you weren't doing much shooting.

[wheelguner]

grayfox ...Thank you for adding a new term to my vocabulary! As a long time habit/hobby, I collect oft repeated "sayings" & descriptive phrases. Two examples.... slicker than a greased snake on a marble floor of slicker than dear guts on a door knob.

[grayfox]

hahahahahahahahaha!!!!!!!!!!!!!!!!!
Deer guts and door knobs.... you got my vote!!!!

[lazyengineer]

I never really payed much attention, and I'm guessing many of my BCG's are not chromelined inside that gas-chamber section. And are running fine. But now that you mention it, yea, I'd probably prefer it if was. If I were shopping for a new BCG today, I'd probably go ahead and get CL'd. Here $90.

https://palmettostatearmory.com/palmetto-state-armory-5-56-premium-full-auto-bolt-carrier-group-8779.html

Keep the bolt as a spare 5.56, and put the Grendel bolt on it, and done.

[Old Bob]

I have a couple of these phosphated, chrome-lined bolt carriers. One on my old 3 gun 5.56mm AR & one on my 6mm ARC AR. They seem to be high-quality BC's.

https://www.crypticcoatings.com/product/cc-bc-0104/

[AK_Reloader]

If one has opted for 1 piece McFarland gas ring,the chrome'd bore will seal better than a Nitride'd bore.

[Ground_Grizzly]

FailZero NiB all the way....

[Arkhangel5]

I have 2 Odin Works black nitrided BCG's, no issues over 9yr so far. Didn't do any research at the time, they were just available at the time of purchase.

SY

[tdbru]

How about these complete BCGs from our own BFT:

https://rexusoutfitters.com/rexus-ultrabcg-6-5-grendel-6mm-arc-22-arc-338-arc-bolt-carrier-group/

I'd be highly surprised if I ever get enough rounds down several barrels to wear one of these out. Probably couldn't wear out a hard chrome one either. Pick what you think is currently the best available (from BFT is my choice) and just use it. This forum has threads on bolts failing at high round counts, but I don't recall any threads on BCGs wearing out. I'm guessing the armorers have seen it on issued service rifles. At the present cost of ammo or components, I couldn't afford the ammo to wear one out. However, like any machine, even with the best maintenance I am sure with enough use, one will wear out a BCG.
best to you,
-tdbru

[SDW]

FWIW, I just ordered a couple of these Toolcraft BCGs in 5.56. One for myself to have as a spare and one for my nephew for his new build:

https://www.spicetac.com/toolcraft-bcg-black-nitride-556/

They sell these in both Nitride and Parkerized+chromeline. I chose Nitride because it's less expensive $15 or so. LOL And it'll be good enough for us. Normally though I'd go milspec with the park+chrome.

There is also a selection to chose between C158 and 9310 steel, whichever you prefer. Same price either way.

Nice thing about this company is that when you put that "$110" BCG in your basket they automatically deduct $11 from the price. Also, there is a free-shipping option, though I paid a little bit for shipping to get the tracking.