
If you ask a dozen gun designers to each label one singular aspect of Eugene Stoner's AR-15 design as the "most important part," chances are good that you'll get a dozen different answers. They may vary from the gun's light weight to its ease of operation to its modularity, but at the root of all of them will be this: That Stoner's design allowed the entirety of the force of the rifle firing to be contained by the barrel extension, bolt head, and bolt carrier alone. This means the rest of the gun can be made from almost anything.
Which brings us to the Lightweight Modern Sporting Rifle 2, or LMSR2. Created by O'Dell Engineering and manufactured in Ontario, one only needs to take but a quick look at the LMSR2's lower receiver to see that it's a bit different from the average AR-15. That is because instead of the milled aluminium shape that one usually finds pinned to an AR-15 upper, the LMSR2 uses the uniquely shaped Omni Hybrid lower produced by American Tactical Imports... and it is uniquely shaped because it is made up almost entirely of fibreglass-reinforced, injection-molded polymer.
And just as Glock experienced, the use of polymer in firearms will always be a bone of contention, especially in the early days of its adoption. But when one considers the ramifications of using polymer in the construction of an AR-15 lower receiver it begins to make a lot of sense. First off, polymer does not deform in the same manner as aluminium; you cannot dent polymer. It simply springs back to its original shape. Also, because polymer parts are molded rather than machined, the ability to mold in features like heavily bevelled magazine wells and textured panels does not come at the cost of increased machine time and wasted material. As a result, the Omni Hybrid lower that underpins the LMSR2 benefits from a huge magazine well with a contoured front panel (for those that like to grip the magazine well), a trigger guard that provides more clearance than probably any other on the market, and big threaded bosses for the anti-walk pins holding the fire control group pins in place. It's also even lighter than even an aluminium lower.
There are also areas in which polymer proves inferior to aluminium. Buffer tubes, for example, typically do not do well threaded into all-polymer lowers. As the bolt recoils towards the rear, the force it imparts on the buffer and buffer tube has been known to snap most polymer lowers at the very rear of the rifle. The Omni Hybrid lower addresses this by incorporating a block of zinc allow in the rear of the receiver. This block is machined to accept the buffer tube threads, and is also drilled for the passage of the rear takedown pin from left to right, so it essentially connects the buffer tube back to the upper receiver through that rear takedown pin. When the rifle is assembled, the buffer tube is threaded into the metal block and the rear takedown pin is inserted through it as well, so that when the bolt recoils to the rear all the force it imparts on the rear of the buffer tube is fed through the metal block and back into the upper receiver through the takedown pin. The only downside to this system is that the rear takedown pin must be fitted quite tightly to ensure there's no play between the pin and lower, as that would lead to more of the recoiling force being imparted on the polymer frame. We should note, however, that even without an upper receiver fitted, the Omni Hybrid lower receiver is still impressively strong. Supported by the magazine well the lower can support up to 285 pounds hanging off its buffer tube, and even survives being run over by an 11,000 pound forklift in a video provided by the manufacturer.

After getting the rifle into the office for testing, the first thing we did was do a complete field strip and cleaning, as we were warned that the uppers were shipped with an abundance of grease within. While the lower receivers are assembled by O'Dell Engineering in Ontario, the upper receivers are procured from either High Standard or Head Down Firearms. The Premium model is fitted with the High Standard assembly and Intro models like this use the Head Down upper receiver. In any case, all uppers are assembled and proof-fired by their respective manufacturers to ensure they work prior to being shipped to O'Dell Engineering and in the case of Head Down Firearms, it's safe to say they are judiciously greased beforehand. After the bolt carrier and its various parts took a trip through the ultrasonic cleaner, and the entire upper receiver and barrel were hosed out, we lubed and reassembled it. While we wish there was more to relate about the gun's internals than that, there just isn't; this is an entry-level AR-15 and the bolt carrier and various sundry parts are exactly as you'd expect. From stem to stern it's pretty much entirely comprised of proper GI-issue, mil-spec components from the Carpenter No. 158 steel bolt carrier body to the standard two-stage trigger group. So, while not terribly flashy, you know it'll all work well together.

Speaking of triggers, the one on the LMSR2 is, like so much else about this gun, entirely predictable. Your average two-stage affair, it has a pretty nice clean break that only got better with some wear, although serious shooters will be glad to hear that the Omni lower accepts any and all aftermarket trigger groups. The only thing different about the LMSR2 is that changing trigger groups requires unthreading the trigger group pins from their anti-walk bosses molded into the receiver, as opposed to driving them out with a punch as one normally would. Six of one, half a dozen of the other.

As its name would imply, the Intro is intended to be an introduction to the AR-15, which is precisely why it has no muzzle device and a railed, low-profile gas block. This ensures the owner doesn't waste any money paying for a flash hider or front sight block they may not want. In the case of our gun, this came in handy as it allowed us to remove the bolt-on front sight and fit a large optic for accuracy testing, giving us an unimpeded view without a giant sight block shadow in the field of view. We also replaced the black six-position GI stock, black hand guard, and standard pistol grip with pieces from Mission First Tactical. And although we had initially figured on stopping there, after putting hundreds of rounds through it without a hitch, chances are good this may be just the beginning for our Intro... we'll make a conclusion out of it yet.

