Del-Ton 16″ M4 Barrel Assembly

As most readers of this blog are intimately aware, prices can vary wildly for AR components – and quality, too, though the two aren’t always tied together. Also, as most readers are aware, I tend to believe in purchasing weapons and components at the upper end of the quality scale, with price as a secondary – but important – consideration.

One of the companies which offers weapons and components at the lower end of the price scale is Del-Ton. They’ve been offering rifle “kits” (everything but the stripped AR-15 lower receiver) and uppers for quite some time, and complete rifles for the last few years.

When a local FFL and friend offered to let me borrow a brand new Del-Ton upper to test, I thought it would make a good comparison with some of the more expensive rifles and components I’ve been reviewing. As it turns out, the upper – which is referred to as a “barrel assembly” by Del-Ton – was, at $505 retail, actually within spitting distance of a comparable Bravo Company upper ($520 plus handguards), and slightly more expensive than a Spike’s Tactical upper ($475 with coupon code from Spikes/$479 from AIM Surplus).

If you’d like to see the complete upper, check out their website – as it was cosmetically identical to the massive number of M4 uppers on the market, I did not spend time photographing the entire upper.

From the front of the weapon –

The muzzle was threaded 1/2×28, as is customary. Although this exact upper was not fired with a suppressor attached, an identical one was, and no adverse issues were encountered regarding muzzle threading.

The barrel itself was chrome lined, 1/7 twist, with a 5.56 chamber. I did verify that the chamber was cut properly. The muzzle device was not properly timed in this photo, but it did come properly timed from the manufacturer. Barrel steel is reported as 4150 by the manufacturer. I noticed that the barrel finish wore more rapidly than the other phosphated barrels I use.

The F height front sight base (not pictured) was attached to the barrel with taper pins, and the barrel was parkerized under the front sight base. These are the “attention to detail” steps during manufacturing that I like to see. Though it’s difficult to tell from the photo, one of the holes was not drilled exactly perpendicular to the bore – this is not a functional problem, but I point it out to show how difficult (impossible) it can be to match an FSB from one barrel to the next once the holes have been drilled.

The taper pins were extremely difficult to remove, which makes me happy, if a little frustrated at the time.

The gas port diameter is .070″. Colt M4s have a .063″ gas port diameter using a 14.5″ barrel, and I have been informed that the 16″ barreled Colts have ever so slightly smaller gas ports. This discrepancy (.070″ vs .063″) might seem huge, but when compared to the .090″+ gas ports I’ve seen on other carbines, it is not terribly oversized. I would prefer a smaller port, but the majority of Del-Ton customers are probably happy with the enlarged port’s ability to cycle very weak ammunition.

I should note that I was pleased by a phone conversation with Del-Ton. The person who answered the phone was able to confirm that all their 16″ carbines have .070″ gas ports within about 30 seconds. I have not always had such quick and accurate access to product information when dealing with other “kit rifle” manufacturers, or even some higher end manufacturers of parts and accessories.

The upper receiver had engraved T markings which were painted white. The picatinny rail itself was within spec when compared to a print. Yes, the gas tube is missing. No, it did not come that way.

I should also mention that removing the barrel nut took a remarkable amount of effort, and I found that grease was not used (or if it was, not an adequate amount) prior to torquing. A well-used AR-15 “armorer’s wrench” proved to be completely incapable of removing the barrel nut, and simply rounded off several teeth. Another barrel nut wrench, designed for slightly smaller nuts, fit snugly, but broke when a massive amount of torque was applied. A new AR-15 armorer’s wrench was acquired, in the assumption that the used one was worn out, but it, too, simply rounded off several teeth. Finally, a Troy TRX barrel nut wrench was purchased, and since it engages about half of the teeth on the barrel nut, it was eventually successful – though a long breaker bar and two extensions were used along with it.

If I only had the AR-15 “armorer’s wrench,” removal of this barrel nut would have been absolutely impossible. It took me several weeks to track down the tools I needed, for I have never encountered such an obstinate barrel nut, even those which were similarly overtorqued and not greased. Due to the damage I caused to both the nut and delta ring assembly when the wrenches slipped, these components were replaced with Colt parts prior to its return to the FFL.

The bolt carrier group is AR-15 profile, with a shrouded firing pin.

The carrier key was staked, but I felt that staking was done too high on the key, because the key material cracked, as you can see. While official guidance on carrier key staking only refers to it not exceeding .025″ above the surface of the key, I have never seen staking like this on a military issued firearm. It would appear that the tool which was used is in need of adjustment. Still, the fact that they actually use some sort of tool instead of a hammer and a punch tells me that they’re a step above several other manufacturers.

Bolt carrier group components were standard fare. The bolt itself did not have any markings, nor is there a reference to any sort of non-destructive testing on Del-Ton’s webpage. However, there was a reference to MP tested bolts being used in newer Del-Ton uppers and kits in their industry forum on This came about in June of this year after a batch of improperly heat treated bolts were shipped out several years ago. It would seem to be impossible to verify whether this bolt was “good” or “bad”.

This is why marking bolts – whether with the ubiquitous “MP” or “HP/MP” depending on the testing done, or with some manufacturer-specific code – is a good idea. If this were my upper, I would replace the bolt with a properly tested unit from a quality manufacturer. However, if I received a Del-Ton upper with a bolt that was properly tested – and could be verified as such – I would simply shoot a certain number of rounds through the weapon to determine if it was indeed “good” – as is my normal practice with my own ARs.

Finally, the extractor spring had a black insert.

I was pleased to see that M4 feed ramps were machined into the upper receiver prior to anodizing, but it was apparent that the barrel extension itself had been ground upon, through the surface hardening. This is only detrimental to the integrity of the barrel extension, and there is no functional reason to do so.

However, the use of dry film lube – visible in the lower left corner of the photo – did impress me, for many budget manufacturers do skip this process.

Despite what might seem to be a lot of negative commentary, I came away impressed with what Del-Ton has done. The upper assembly was a step above what I was expecting, and it (and the several identical uppers owned by the FFL who loaned me this one) functioned without a hitch, although the round count through this upper was low, as a fair number of rounds had already been fired and/or were observed being fired through the other uppers.

It certainly offers more of the features that interest me than the other, less expensive Del-Ton offerings. That said, for “hobby gun” usage, as long as those other ARs had the same chamber dimensions and gas port diameter as this sample, they would probably prove to be as reliable as their owners expected them to be.

I think this upper will appeal most to people who already own and like Del-Ton products and want something with features such as 1/7 twist and a chrome lined barrel. For $505, I would personally find another upper to purchase.

Edit: One additional factor in my decision making process was that Del-Ton’s warranty (60 days for this upper assembly) is void if steel cased ammunition is used in the weapon. Since I know that steel cased ammunition should not cause significant problems in an AR-15 with properly machined components – such as this upper – I can only assume that past Del-Ton uppers were not built to the same standards. I would hope that they realize their newer uppers are perfectly capable of functioning with steel cased ammunition and adjust their warranty accordingly.


1 Comment

Filed under Firearm Components

One response to “Del-Ton 16″ M4 Barrel Assembly

  1. Bart

    I would like to comment on your edit that I have a Del-Ton 16″ 1:7 mid-length upper that WILL NOT fire steel cased ammo. It will get through 1-6 rounds before a case will seize in the chamber, requiring a long steel rod down the barrel considerable force to remove the lodged case.

    Upon inspection I there appears to be a small burr in the chamber that prevents steel cases from ejecting properly. I believe the brass case’s more compliant nature allows it to be unaffected by this burr.

    I have not had a single issue with any brass cased ammunition.

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