The Gibbz Arms G4 16” side charging AR-15 upper defines performance in this industry. For shooters interested in a side-charger, this is the ultimate 5.56 model. Here’s an in-depth look at some of the salient, value-adding features.
Tight Tolerance
Gibbz Arms hails from a background in the aerospace industry, and as a result we’re accustomed to working with extremely tight tolerances. Typically for us this means +/- 5/10 (.0005”) of a thousandth of an inch.
To put it this way, wide open tolerance for us is 5/1000th (.005”) of an inch. For the manufacturing of all of our upper parts, we uphold this minimum, and all parts meet it, if not tighter standards.
This exceptionally tight tolerance has enabled us to machine an upper the parts of which mate up perfectly, offering an unbelievable fit and finish that really must be experienced; our words here do it no justice.
Hand Finished
In aerospace, if 5 pieces out of a million get rejected by quality control, that’s considered a failure. We apply that same standard of quality to ourselves.
As a result, we hand-finish everything to ensure that every single burr and aberration is polished away completely. Our parts are scraped, buffed, tumbled, and then inspected again to make sure that all machine marks are completely gone.
Only then do we send the parts to be anodized, and even after that we inspect them a final time.
6061 Billet Aluminum Upper Receivers
We’ve chosen 6061 aluminum alloy for our billet uppers not just for its affordability, but for its machinability. It is a somewhat softer alloy, making it easier to machine and finish, and also more forgiving.
But the performance of the alloy is also considerable; it offers high strength, low weight, and significant corrosion resistance as well.
Side Charging Roots in Tradition
When Eugene Stoner first designed the original platform that would ultimately go on to become both the M16 and AR-15, he designed it with a carrying handle that protected the rifle’s rear sight; in front of this carrying handle was a hook that served as the charging handle.
Stoner wanted the charging handle to be mounted forward of the carrying handle, not at the rear, like most modern AR-15 rifles.
However, in testing, the forward charging handle proved to be inadequate. It got too hot too quickly, and it proved to be difficult to access due to its location. Worst, it was hard to get a lot of leverage on it since it was not positioned ergonomically. Among other things, this made clearing jams extraordinarily difficult.
Because Stoner was already too invested in the tooling for the upper the way it was, the workaround for the forward mounted charging handle was the T-handled rear-charging handle we know today.
Our personal conviction is that if Stoner were to go back to the drawing board and redesign the rifle today, without the restrictions aforementioned, his workaround would not be a rear-charging configuration, as is the modern status quo, but a side charging AR-15 upper similar to what we’ve produced in the G4.
A Side Charging AR-15 Upper Compatible with All Mil-Spec Components
All stock mil-spec components are compatible with the G4 side charging AR-15 upper receiver, including the bolt carrier group. The only thing you need to do to ensure consistent performance is replace the BCG’s standard cam pin with a Gibbz Arms enhanced cam pin, which takes all of a few moments.
If you buy one of these uppers, it comes with the cam pin indicated, so this is not something you realistically even need to think about.
The purpose of replacing the standard cam pin is that the enhanced cam pin prevents the stock cam pin from falling into the side charging track, which could in theory impede performance. Otherwise, these uppers are fully compatible with all mil-spec components.
Non-Reciprocating, Side Charging Superiority
Let’s say you go to lock your bolt back; with this side charger, you can do so with one hand, improving operator friendliness and general ergonomics.
There is also a PDQ lever on the upper that allows you to release the bolt carrier group quickly and easily, again with one hand, and realistically with one finger. You can do so while maintaining your “ready/fire” grip as well, while keeping your eyes and sights on target.
Another benefit is that you don’t need to break your cheek weld in the event of a malfunction. You can just remove your support hand from the handguard and use it to cycle the charging handle either to clear a jam, manually charge the action, or whatever else needs to be done given the nature of the malfunction.
The configuration of the bolt carrier door also greatly reduces back-gassing when you’re shooting suppressed, which helps to keep hot, high pressure gasses away from your face, venting them primarily out of the barrel or ejection port.
Sub-MOA Accuracy
Though this is not a benefit of the side charging configuration of this upper, the barrel is capable of sub-MOA accuracy out of the box, even with factory ammo. You just need to find the right load, choose an optic and sight-in, and you’re good to go.
Moreover, the Picatinny rail, which is integral to the upper receiver itself, is aligned with the bore, enabling exceptional accuracy. It also streamlines sight-in because regardless of what optic you put over the receiver, it’ll basically be in-line with the bore from the moment you mount it.
For Other Questions About Our G4 Side Charging AR-15 UpperReceivers
You can learn more about the G4 side charging AR-15 upper receiver on our website, but if you still have questions before you get one or are not sure if this or another one of our models is best for you, feel free to get in touch with us.