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AR-15/M16 NiB-X® COATED UPPER RECEIVER Reviews & Ratings

Stripped receiver has WMD’s NiB-X® nickel boron coating inside and out to provide an exceptionally tough, ultra-smooth surface finish for outstanding wear resistance and lubricity. A ceramic topcoat is applied for color on the exterior only, leaving the nickel boron exposed inside to keep friction with the bolt carrier to the absolute minimum. Works great with standard carriers, too, but even smoother with nickel boron coated bolt carriers, including WMD’s NiB-X® coated carrier, available separately. M4 feed ramps ensure reliable feeding.

SPECS: 7075 T6 aluminum, NiB-X® coating with matte ceramic finish, Black or Flat Dark Earth. Stripped receiver only. Fits standard AR-15/M16 lowers, and accepts standard barrels and upper receiver parts. .250" dia. pivot/takedown pin holes. M4 feed ramps.

See all of our AR15s and AR15 parts here.

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Reviews Summary

Customers have mixed feelings about the AR-15/M16 NiB-X® Coated Upper Receiver. Many appreciate its fit and finish on various lowers and the overall performance when paired with compatible components. However, concerns about poor coating quality, overspray, and machining issues frequently arise, leading to feelings of disappointment for some purchasers. Overall, it's a product with potential, but quality control needs improvement.

What Reviewers Are Saying

Product Quality

45%

A significant number of reviewers expressed disappointment regarding the quality and finish of the upper receiver. Concerns ranged from overspray on the nickel boron coating to machining marks and uneven exterior finishes. Some noted that the product's performance is solid after adjustments, yet others reported significant dissatisfaction, leading to regrets over their purchase.

Fit Compatibility

40%

Many users highlighted the fit of the upper receiver with various lower receivers, noting that while some experienced a tight fit, others had issues aligning the pins or fitting them altogether. The need to file down pin holes for compatibility was a common complaint, emphasizing that fit can vary significantly by setup, affecting user experience.

Performance

35%

Despite the concerns about quality, several customers praised the performance of the upper. Reviews indicated it worked smoothly with compatible parts, including nickel boron bolts. Positive feedback noted that once everything was properly fitted, the upper provided a satisfactory shooting experience, suggesting it has the potential for great functionality.

Appearance and Finish

30%

While some customers complimented the aesthetic appeal of the FDE finish, several reviewers expressed dissatisfaction with the overall finish quality, stating it appeared overly shiny or was applied too thickly in certain areas. Mixed reviews about the coating durability and smoothness imply that while the upper is visually attractive, it may not hold up under scrutiny.

Quality Control Issues

40%

Several reviewers reported quality control inconsistencies, notably regarding defects, overspray, and poor surface preparation before shipping. These recurring issues affected user satisfaction, with some mentioning they would consider returning their purchases. The call for improvement in quality checks is evident, as many noted that further inspections could enhance customer confidence.

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Needs Tweaking and QC

Bought this awhile back. Came in wonderful condition but one: Pivot pin paint to thick, esp on front. After using a mallet several times thinking it would wear in with shooting, I gave up and used a drill bit on very, very low setting and speed and cleaned up pivot holes. Front was worst. After that, no problems. Am using a PSA NiB BCG and POF Roller Cam pin also. All together its incredibly smooth! Paint showed no signs of chipping or flaking, assembled nicely. Would love to get a few more in time. If WMD can work out the QC with the pivot pin I'd give it 5 stars easy!

Smooth as glass, but holes too small

The finish looks good and the interior surface is smooth as glass, but the takedown / pivot pin holes were slightly too small. I could insert the rear pin with some help from a rubber mallet, but the front pin was absolutely NOT going in. I had to use a little, round pin file on the front hole to get the pivot pin in. It's really snug now.

Tight Tolerances but Builds Easy

I was a bit of a Nickel Boron skeptic as there seems to be a new coating for gun parts every couple of years. I read reviews and some of the properties of the coating are very compelling. While I was not completely sold, my father in law was and asked me to build him an AR with all the moving parts NiB coated. I went ahead and grabbed one of the WMD NiB Uppers in black and matched it with a MAG Tactical Lightweight Lower. The finish on the outside of the upper was a bit shiny here and there, but the internal NiB coating was uniform and I didn't notice any flaking or high/low spots. It also matched the lower receiver nicely, though there was a shade or two in different darkness's. I set up the upper with a WMD BCG along with various other NiB parts for the trigger group and the charging handle. Everything went together well, but the receiver pin holes did need to be filed to remove the coating so the pins could slide through. This isn't a big deal for me as I like a tight fit and the ability to file to size left me with no rattles. After shooting several hundred rounds through the upper all of the NiB pieces have mated nicely, evidenced by a shine as the surfaces are worn. The only negatives of this upper are: 1) the gas tube cutout: it is a little oversized and my gas tube rattled just a bit. While not a huge deal, I am the kind of guy that will break down a buffer and put material in there to keep the weights from moving around. 2) Cleaning: the nickel boron coating is supposed to make the parts easier to clean, but honestly, it is about the same or worse as anodized or parkerized finishes as you can see the dirt. It also doesn't wipe off as easy as chrome. Overall, it isn't a deal breaker, just a small inconvenience. In the end, I do like this product and I bought a couple more for a 300 BLK build in FDE and for a Lightweight build I did for my wife.