Are there any other advantages to the chrome bolt groups other than ease of cleaning?  ...any drawbacks?

OK, last time we had one of these questions, and I posted the fact that, over time, hard chrome will flake off the assmbly, and imbed itself in the walls of the upper, some guy came on and all but called me an idiot for posting that.
When I responded by offering to send him the early GI plated gas carrier key in my parts box, with half the plating worn off, if he would tell me where he thought the plating went, all I got was silence.

The plated assemblies aren't all that much easier to clean either.After all, most of the fouling is deposited on the bolt tail, which is easy enough to clean, and the inside of the carrier recess for the bolt, and that's already plated.

I promise you, if there was any significant advantage to hard chroming the exteriors the Armed Forces would still have plated parts. As far as I'm concerned, it's just another way for some supplier to take a few extra bucks out of your pocket. I've had the chromed pieces, and sold them all off years ago. Spend the extra bucks on a couple of extra mags. You'll get far more value out of them.[:D]

No Advantages!

Maybe a slight reduction in wear to your upper due to chrome's slippery (if you will) property.

But that would only be realized after 10 million rounds!

Sham,

Funny post. I got my head ripped on the same topic except barrels.  Plating is plating and I don't care if you plate titanium, it's still a plate not a smelt. Oh shit, here I go again!

Markum,

Got ripped for that one too!  My basic statement was chrome makes your barrel last longer cause it wears instead of the steel but not as fast cause it has less surface friction thus the bullet is a little faster out the barrel. Oh yea, I used the word Sacraficial which is synominous with plating. Damn, I just won't learn to keep my fingers shut!

The only advantage is if you are building a retro model AR-15, It just has to have that no foward assist/plated bolt carrier & Bolt.

Now who knows where to get an early front sight, You know the tall thin one, Like the one on the first AR-15  they show on the History channels "M16 Tales of the gun"?
I gotta have one of those too!

Know what you mean, Tom.  Just read a response to a post I put on another thread where a fella was asking about who did barrel hard chroming.  In my note, I mentioned that I'd had an M1 carbine barrel hard chromed many years ago, and that after several thousand rounds of mainly bump firing it started to peel a bit at the the throat.  This guy solomnly assured me that it couldn't have been hard chrome, since real hard chrome wouldn't do that.   Grrrrr!

Oh well, nobody ever promised me either a fair world or fully educated web posters[:D]

I guess that chrome peeling on my 69 Charger's bumper isn't real chrome afterall it didn't even have bullet passing through it!

I posted my name and address on the last post about hard chrome and you never sent the "hard chromed" key that "flaked" properly done HARD CHROME does not flake.  Decorative chrome flakes or chroming to improperly prepped metal flakes.

If you doubt me contact these guys [url]http://www.apwcogan.com/[/url]

Hard chrome does not "flake" it is bonded to the metal in such a way as for that to be impossible.  I have had 3 firearms 100% HARD chrome plated and there was never any "flaking" on those guns.  I have seen people reccomend places to get parts chromed and they post links to "decorative" chrome.

Accurate Plating and weaponry will hard chrome your bolt, carrier and entier trigger group for $50 BTW.  I would not trust the chromed bolt groups I have seen prechromed for sale as they are obviously NOT hard chromed just from looking at them.  If it has a bright silvery finish its not hard chrome.

Edited to add:

There is not one instance of a hard chromed bore of a military weapon "flaking"  If you will find the post where I posted my name and address so I could stop the rampant spread of misinformation that is here there is a poster who posted after me who supported my position and I thought I had seen the last of YOU after all I got was silence and no HARD chromed key in the mail.  I will go now and be finding references for the original poster now to assist him.

I had 3 weapons done by Armoloy.  Here is their quote.

ARMOLOY technology has a refined process where its 99% chromium coating permeates the microscopic surface of metal surfaces creating 100% bonding characteristics that [red]will not allow chipping, flaking or seperation from the basis metal.[/red] Consumer tests conclusively prove that surfaces treated with Armoloy deposits of .0001/.0002" per side are harder and have superior anti-friction, anti-corrosion and increased lubricity properties.

So in conclusion you will have a longer lasting, lower maintenance part which will aid reliability for about $50 extra bucks.  Make sure you keep your ejectionport cover closed and noone can tell if its hardchromed or not.  I advise to get a Colt or Bushmaster bolt or carrier to have this done to and use a reputable company like Armoloy or AP&W if you want this option to be certain you wont have problems with hydrogen enbritlement and that the surface will be properly prepped

I don't think anyone will argue the benifits of (hard) chrome plating. It does last longer, has corrosion resistence, and even cleans better. LIke it or not, nothing lasts forever and given this as a truth then it has a failure mode.  So far, I have seen posts that chrome is not sacraficial so it must not wear and it will never flake. I must conclude then it lasts forever. NOT.

Plating is a bonding operation. In short, the metal seaps into the intergranular structure of the base metal kind of like leggos plugging into each other.  It is not a smelt where the mix is homogonous.  The plating also a dposition process which means small amounts are deposited a little at a time till the desired thickness is acheived.  There are some really great processes for this but once again it is not a smelt.

I would like to also add that I am a VP with a company with over 450,000 sq/ft of manufacturing that manufactures engineered metal products for such things as F16s, 747s, etc.  We have one hell of a plating department and I have eight MEs reporting to me and am a ChemE by education. If you can really do a plate operation that does not have flaking in the DFMEA or process FMEA, I would like to offer you a job. Never is a really really long time.

By the way, one benifit not mentioned is it makes one hell of a nice shiny target.

I never said it lasted forever I said it didnt flake or lodge in the upper receiver.  People on this board in previous threads (like the one where I posted my address) said the chrome "flakes off" and there are chrome "chips" that would lodge in the locking lugs or imbed in the receiver.  That is not hard chrome.  The hard chrome will wear away on a microscopic level and not leave chips you can see.  It wears, it does not flake.  Noone said anything lasts forever.  If you can find that quote please point it out to me.  Finally hard chrome is not shiny.  All my hard chromed guns have a nice matte flat grey appearance and only the parts that rub together are shiny which is no different that when the parkerization wears off the working surfaces.  Hard chromed carriers will be light grey instead of charcoal grey.  They will be non reflective.  If you keep your ejection port cover closed they you will not even see the light grey either.

To conclude:

Hard chrome does not wear the upper reciver. It decreases wear through reduced friction.  Myth #1 Dispelled
Hard chrome does not "flake" and lodge in your lugs it simply wears away like any other coating. Myth #2 Dispelled
Hard chrome will INCREASE the life and reliablity of your bolt and carrier if done properly. Myth #3 Dispelled
Hard chrome is NOT shinny it is a dull matte grey. (Unless you TRY to make it shiny with polishing)Myth #4 Dispelled

If I can just keep those 4 myths from resurfacing I think I will have truly made a contribution to this forum.

Will ARMOLOY technology Hard chrome a rifle Bore?

Only .30 cal and up they dont do .22 bores I already asked that 2 years ago.

DevL,

How about this.  I haven't seen in any of the replies about wear on the receiver.  I don't know about it, but I have seen posts to the effect that the hard chrome bolt and B/C will wear the inside of the receiver and (can't recall if they said this) the locking lugs.  Do you think there is anything to this?  I ask now because I happen to have a fully HARD chromed bolt assy and bolt carrier.  None of it is shiny except the polished inside of the carrier.  It's to go in an M16 - should I beware of receiver wear and not use it in the select fire?  Anyone?

Edited to specify that I meant wear as in excessive wear beyong what a normal unchromed bolt/bolt carrier will cause.

The Maryland AR-15 Shooters website has an article in which chrome plated carriers and bolts are not recommended.
[url]http://groups.msn.com/TheMarylandAR15ShootersSite/theseriousar.msnw[/url]

I don't have a recommendation if it's better or not to do this, the military seems to think that chrome plating the inside of the carrier is enough.  I did have a Stewart Wilson AR10 which had a bolt and entire bolt carrier chrome plated.  The action was very smooth, but I cannot say that it improved reliability, or if the upper receiver was wearing any faster.

The friction between the two will be reduced.  Hard chrome is used in industry to increase the life of parts that work together like carbon steel/stainless steel, stainless/stainless (stops galling) and yes even aluminum/carbon steel.  The carrier may wear less so the upper receiver will see a greater "percentage" of the wear but the wear itself will be reduced overall and the life of your upper receiver will be increased.  

As for the US military not using the chromed carrier...

Stoner himself called for the hard chromed parts.  You have to look at it from a cost/benefit ratio like they do.  If it costs them $100 for a bolt and carrier and $150 for a completely hard chromed bolt and carrier the hard chromed version MUST give in EXCESS of 50% more life to be used.  If not its more cost effective to just put a new bolt and carrier in when the time comes.  I personally do not think hard chrome is the best "economic" choice but it will result in a longer lasting, lower maintenance, more reliable part provided it is done correctly with good base parts.  Is it worth the cost to you?  Only you can decide.

If you use the search function and check the archives you will find there are many more people who have had increased reliability and life in full autos they own or no problems in semi autos than people with problems.  Most every negative response comes from someone reading that Maryland AR15 Shooters Site and saying "I heard of a guy who broke 3 bolts".  The rest come from someone using a poor base part or improperly chromed part.

I challenge anyone to find documentation that shows that the upper receiver is worn faster with a chrome lined carrier like they say on the MarylanAR15 site.  I tried hard to find such a document and have always come up empty.

This reasoning is much like the bandwagon people jump on to stick to "milspec" single stage triggers because triggers with set screws will go "tits up" because Murphy says so.  While the new SPR in use in A-stan has a Knights 2 stage trigger in it with 2 set screws and has never had a malfunction reported.

The only time a hard chromed part has ever been accused of CAUSING wear and problems is in the AR15 community.  Everywhere else for every other mechanical part and every other weapon it improves function, reliability, corrosion resistance, etc.  There are no documents to back up the hearsay to prove otherwise.  Think about that for a good long time.

Devl.,
Thanks for the links to the companies.  I was thinking of getting a chrome bolt and bolt carrier for my AR15, but was hesitant since I was unsure of the original source of the parts.  I can say that there was a difference when you cycled the action on my Stewart Wilson AR10 and my stock AR10A2.  I can say that there was no wear noticed on the chrome parts.  

Also, my Sterling AR-180 has a chrome bolt, but the inside of the carrier isn't chrome plated.  This is the way it came from the factory, I've owned it new since 1985.

You've got me digging now looking for why they discontinued the chrome bolt carrier, but cost reasons certainly can be it.  

DPMS sells chromed bolts & carriers, I even hear that their Retro (No foward assist notches) carrier is available.

   I had ARMALOY finish a steel Colt Commander for me way back in 1975. I carreid and kept the gun until the eighties and sold it. Recently  ran into its owner and was surprised to see he still had it. It STILL looked damned fine too. I personally like Armaloy and have had a few weapons treated by them over the eyars. It IS very hard.
 My concern would be its SO hard would it damage other parts??

FN in MT