As any firearms instructor knows there are times when training with functional firearms is impractical or just unsafe. In those situations one option is to use non-functional "dummy guns" that replicate the look and feel of actual firearms, but are incapable of chambering live ammunition.
Although I've acquired several replica handguns for training purposes over the years, I never needed a training rifle, until I was scheduled to teach a seminar on "Firearms for writers" at a location where actual firearms were prohibited.
I needed a replica of an M4 Carbine with a rail that would accept actual carbine accessories and that closely replicated the actual weight of an M4. One of the leading manufacturers of non-functioning training firearms is Ring's Manufacturing, of Melbourne, Florida. Ring's produces a large variety of simulated firearms under the trade name "Blueguns." I contacted them to see if they could meet my needs and they sent me their model "FSM4FTR M4 Flat Top Open Stock, Fwd Rail."
This model replicates a semi-auto M4 style AR with a 16" barrel, railed receiver, and four position railed hand guards. The replica is molded off an actual firearm in impact-resistant polyurethane with steel reinforcement for extra rigidity. The "Blueguns" line are all molded in a shade Ring's calls "Law Enforcement Blue" to easily distinguish them from actual firearms. The guns are cast in one piece, to the actual size of the original firearm, and do not have any moving parts.
I was impressed with the level of detail of the replica. The original manufacturer's marks and serial number of the actual firearms are clearly readable, as are the selector markings. More importantly, for my purposes, the casting of the rails was precise enough for me to install an Aimpoint Pro red dot sight on the receiver rail. I was concerned the sight mount might "dig in" or damage the plastic of the molded rail, and that might cause the sight to loosen or even come off when handled, but this turned out not to be an issue. The sight stayed in place even after much handling with no sign of any damage to Bluegun rail. The replica included metal sling mounts on the side of the barrel and bottom of the extended stock. These readily accepted my sling.
Once the Aimpoint and sling were installed this gave my students in the seminar a chance to handle a replica of a M4 with a functioning red dot scope to learn both how the sight worked and get an idea of the overall heft and feel of a modern military style rifle.
The replica is not perfect: Under close examination some casting flaws and holes caused by air bubbles in the mold are visible. For the purpose these should not be a problem though. This is a training tool, not a high end collectible, where minor flaws would detract from the value.
In addition to the standard "Blueguns" line, Ring's also offers replicas weighted to the exact weight of the real firearms, molded polyurethane accessories such as knives, impact weapons, and radios, and a line of even more realistic painted replicas for movie and theater use. (This makes sense as Ring's originally started as a prop house providing firearms for the movie industry).
The Ring's Blueguns are available from many distributers and retailers. The suggested MSRP for the M4 railed model I used is $177.15.