As I posted yesterday, I recently disassembled the Spike’s Tactical 5.45×39 upper receiver assembly and checked it for corrosion. I had intended to post more photos last night, and apologize for not doing so when I said I would.
As noted, the weapon was very dirty. If you are not familiar with my use of this upper, it is important for you to understand that I have fired over 7500 rounds of corrosive ammunition through it, over a period of a year, without one proper cleaning.
The first thing I examined in detail was the barrel. There were no signs of corrosion on or in the barrel, or any other melonited part, for that matter. The gas tube and front sight base were also melonited, along with the handguard cap. Be advised – you can click on the photos for bigger pictures, and when I say bigger, I mean BIGGER. These photos were taken immediately after disassembly, and the barrel was not cleaned prior to taking them. I have run a BoreSnake through it since, and there are no signs of wear or corrosion there, but I’m still working on a decent enough photo of it.
Compare this with the Smith & Wesson 5.45 AR-15 that I put a similar amount of corrosive ammunition through over a similar period of time, also without cleaning. Its barrel was chrome lined, with a phosphate exterior finish. The bolt was originally phosphated, but I electroless nickel plated it after seeing some corrosion – closing the barn door after the horse had escaped, I know.
In comparison, the Spike’s Tactical 5.45×39 upper’s bolt had been plated with Nickel Boron by FailZero from the start. While it certainly looked better than the competition, there was minor pitting visible once I cleaned away all the carbon. Again, click on the photo for a much larger version.
So it would seem that Nickel Boron is far better than phosphate as a corrosive resistant finish, but is not corrosion proof. Although I would have to have had two otherwise identical parts, one nickel boron and one melonite, subjected to the same treatment for me to conclusively say that melonite offers superior corrosion resistance, the almost-new appearance of the melonite barrel – after over seven 1080 round tins of corrosive 5.45×39 surplus ammo – impresses me.
On the left is a Spike’s Tactical nickel boron plated bolt carrier group for 5.56, and on the right is the same in 5.45×39. Both have seen fairly extensive use, but the 5.45×39 version looks just a bit more disheveled.
Interesting that the melonite held that well! Any notable difference in how hard it was to get the carbon off the different treatments?
One pass with the boresnake and the bore was practically spotless – I’m sure it could still benefit from a few patches, though.
I gave up on the inside of the carrier as I was not able to get all the carbon out without a hammer and chisel. I think hard chrome is much easier to clean after a long period of time has passed. I wish Spike’s still sold hard chrome BCGs, and I won’t ever be getting rid of the one I do own.
My question is what happens when you use different coated parts together? I am building an AR15 and the bolt carrier group is from Wilson Combat and coated in NP3 for Wilson Combat by ROBAR. The stripped bare receivers are also from Wilson Combat but they do not have any finish on them except a cheap gritty anodizing. I want to get the receivers coated in something so, should I send it to ROBAR for NP3 coating as well, or try Cerakote? What happens if I Cerakote the receivers inside and out and have a NP3 bolt carrier group running in it. Will I get asbestos like particles in my lungs from one of the finishes because they are not the same?
No, you won’t.
So NP3, Cerakote, what should I get the receivers inside outside done in?
Well, my question in the other comment thread was whether or not the upper receiver had dry film lube inside. If it does, it is probably a pretty decent receiver. As for what to do, well, you could have the whole rifle cerakoted for the price of having Robar do NP3 on the receivers.
Not having the whole gun coated. The rail for this build is a Daniel Defense rail that is $432 and a couple other parts that sent this build into the red, I got carried away. Not going to paint over those parts because I want to switch parts around in the future and have them keep there factory value. Just looking to coat the stainless steel barrel, receivers, buffer tube, and maybe the gas buster charging handle. The anodizing on the receivers is really gritty so it needs a coat of something.
Ever heard of Krylon? You can always rip it off if/when you decide to resell it.
Also any anodizing, even gritty, will protect the aluminum. It protects the aluminum, it doesnt have to be pretty.
Sounds like you are not happy with the receivers at all – why not sell them and get another set? AIM has Nickel Boron plated receiver sets for $220 – I’d buy a set, except they have the RGuns logo on them, and I hate RGuns with a passion. You might not care that RGuns is run by a bunch of lying pieces of trash, so it might be a good option for you.
My receivers are Wilson Combat Matched Set, I just want to get them and the stainless barrel coated in something high quality. I think I will try the Cerakote.
As I understand it Melonite is a treatment of the steel, right? Could bolts, carriers, trigger assemblies be ‘Melonited’ like the barrel, gas tube etc?
I am very interested in a Spike’s 5.45 upper- but am concerned about a reported lack of dependable mags. That and AIM is out every time I decide to get one.
They could, but due to the high temperatures involved, the Melonite process would have to be done while the bolts, carriers and so on were “in the white” – no heat treatment. Also, you will notice that the barrel extension (see the 4 OCT post) is also nickel boron. If a complete, headspaced, gas-port-drilled AR-15 barrel is Melonited, chances are that the barrel extension will come loose, either immediately or down the road.
Since the headspace is set when the barrel extension torqued in place to 150 ft/lbs, and the gas port location is then drilled to match the position of the index pin, the Melonite process has the potential to render useless an already complete barrel. Tom at Spikes wisely chose to have the barrels profiled and Melonited prior to attaching the barrel extensions, which were nickel boron plated, and drilling the gas ports, which, unfortunately, cannot be melonited due to the order of operations required.
I have both C-Products and Asc 30-rnd magazines. So far, no problems with either. Can be had for ~$13-$15 per. I load 25 rounds. Web chat indicates both C-P and Asc mags made on same tooling.
http://www.cdnninvestments.com/ar530blstnot.html
http://www.google.com/products/catalog?q=5.45×39+magazines&hl=en&rlz=1C1_____enUS442US442&nord=1&prmd=imvns&bav=on.2,or.r_gc.r_pw.,cf.osb&ion=1&biw=1680&bih=963&um=1&ie=UTF-8&tbm=shop&cid=6379363567431734206&sa=X&ei=NvyUTuy-C6KHsgLVsOXvAQ&ved=0CGAQ8wIwAg
I am shooting Spikes and Oly uppers with the Russian surplus ammo. Rock River Arms lower with 2-stage NM triggers. Standard springs that come with the RRA NM trigger–no ignition failures. Early days, but very pleased so far. Recoil seems noticeably less than 5.56. Accuracy seems good.
The Spikes upper is Melonited inside and out–bore and gas tube included. I suspect *anything* steel can be Melonited.
Aimpoint red dot needed no adjustment when switched between Oly and Spikes uppers. Using RRA Tactical Riser for sight height.
Any questions…???
Peter H
Forgot to mention–Oly upper is stainless bbl with standard Parkerized (phosphate) BCG.
I’m not 100% satisfied with my Spike’s NiB BCG. I’ve got roughly 3,000-3,500 rounds on it and the discoloration is terrible. Don’t call me gay for that. Performance wise its great. It still needs lubrication (even tho I’ve read claims that NiB coating is ‘self-lubricating’… even hookers aren’t… nevermind), there are wear signs wear it contacts the receiver on the carrier, again not a big deal but I plan on keeping this for a long long time so we shall see how it holds up. The BCG doesn’t just ‘wipe clean’ as I’ve heard others say it should, even hookers don’t… nevermind. It still takes a good deal of scrubbing and soaking and I still have to use a penny or spent case to scrape the carbon off the bolt. The finish wear the carbon is most on the bolt seems to be pitting and junky like yours. I don’t shoot corrosive ammo so I’m not sure what caused this, and 3k rounds really isn’t that much. For the price paid, I really expected better resistance to carbon and better resilience in the color and shine of the coating. But again, the #1 important thing is that I haven’t had one malfunction in that 3K rounds due to the BCG, (did have a pmag feedlip break and cause double feeds and all sorts of hell but that’s another story). As always, love the reviews and keep up the good work.
Yeah, they sure looked “pretty” when they were new though… The discoloration seemed to occur with the electroless nickel plating I did for AR bolts/carriers as well, and I just chalked it up to improper technique on my part – but it would seem that the problem extends to all nickel plated bolt carrier groups.
I think the hard chrome BCGs are a better choice – again, too bad they aren’t sold by Spike’s any more, or another company that makes/sells quality bolts.
What about bravo company’s ionbond bolt? I heard those are supposed to be the best bcg finish/coating.
I’ve never seen one, can’t comment.
Ionbond isn’t as durable as hard chrome.
Get a AA piston kit and none of that will matter. just my .02 cents
Great info.
So the S&W barrel was corroded at the threads, but how was the bore and chamber, and how did the gas block and gas tube fare?
Thanks.
There was rust on the inside of the gas block. Unfortunately, I didn’t get any pics of the bore, and my memory is not good enough for me to make any definitive statements about the condition of that bore at that time.
Very informative article, thank you! I was wondering if you noticed any increase in reliability while running the nickel boron bcg?
I have to ask, what’s the story with rguns? I’ve been considering them because their prices on nickel boron receivers and bcg’s are good, but then I saw your comment… Also, thanks for all the info you share. You’ve helped me make some better decisions than I would have on my own concerning my new interest in AR’s.
I don’t like the way they play games with orders. They’ll take your money and tell you that something is in stock and ready to ship, then hold your money until you call to cancel the order. When you do that, they’ll tell you that the order “shipped this morning.” Then you’ll get a UPS shipping notice created after your call, and you’ll see that the item wasn’t even picked up until the next day. CMMG does the same thing. I will never deal with either company again.
Excellent review. (as always) I have always wondered how the melonite holds up to corrosive ammo.
I have a Adams 5.45×39 upper that has a melonited barrel and BCG. At first I was pretty anal about cleaning it right after use of corrosive ammo but have been extending the length of time lately and monitoring closely. No signs of pitting so far but I haven’t went nearly as long as you have without cleaning.
Thanks much for providing the answer that nobody else could. Appreciate your efforts.
Im sure the 5.45 x 39 sees a lot more corrosive ammo and primers than the 5.56 so I would expect it to look a little “more disheveled” I have an Adams in both calibers and a 5.56 and 5.45 with NiBoron bolt carrier groups and the only difference in any of them is the 5.45 in both sees more corrosives as it should because of ammo choices. In both of the 5.45’s they are a little more “disheveled”.