Gunsmithing AR-7 Rifles

Originally designed by Armalite’s Eugene Stoner, the AR-7 rifle was intended for but never adopted by the United States Air Force as a survival rifle. It is a compact, semi-automatic blowback-operated .22 LR. It is unique among take-down .22s in that both the action and barrel may be stowed inside the stock. Furthermore, it is impervious to weather and will float once stowed in the stock.

Another highly desirable trait of the AR is the major components like the trigger/sear, hammer, magazine release, firing pin, extractor, and ejector can be fabricated from flat stock with simple hand tools. Use the original as a pattern, such as photocopying the part and gluing it onto the flat stock. Sawing, filing, and time is all that is needed. This is ideal in a situation where parts can’t be mail ordered. S. Survival AR-7 Rifle.

AR-7s have been produced by Armalite, Charter Arms, Survival Arms, and Henry Repeating Arms, its most recent incarnation. They come equipped with an extra eight round magazine that may be stowed in the stock. In the past, longer 10, 15, 25, and 50 round magazines have been offered by various makers. One thing Henry Repeating Arms did to lighten the AR-7 further was to replace the steel lined aluminum barrel with steel-lined carbon fiber barrel.

Another improvement was replacing the plastic stock with a more durable ABS type material. To disassemble it, first remove the magazine and check the action to insure that it is not loaded. Unscrew the barrel nut and pull the barrel straight out. The receiver may be removed by unscrewing the nut found in the grip cap and then pulling the receiver straight out. By pulling off the butt cap, stowage compartments may be found for the barrel and its nut, receiver with magazine stacked, and the spare magazine.

Earlier AR-7s had aluminum receivers and the current Henry Re-

peating Arms model uses zinc. To disassemble the receiver, first push back the bolt slightly. Pull the bolt knob out of the bolt and allow the bolt to slide forward and out of the receiver. The two recoil springs may or may not come out with the bolt. You can reach in with pliers to pull them and the recoil spring guide out. To disassemble the bolt, punch out the firing pin retaining pin. The firing pin may then be lifted out.

A roll pin punch is used to knock the extractor out and the extractor and extractor spring may now be lifted out of the bolt carrier. Next, re move the screw holding receiver plate. Lift it up carefully as you don’t need anything to go orbital. Note, sometimes the hammer and trigger may be displaced by the merely removing the plate. The magazine catch is removed next followed by the magazine catch pivot pin. The ejector may be pulled down and out of the receiver. De-

tension both legs of the hammer, allowing the hammer assembly to be lifted out. The hammer pivot pin can be lifted off and the hammer spring slid off the hammer. Next, lift out the trigger pivot pin. The hammer/trigger spring support pin should fall right out when the trigger is lifted. The safety snap ring may be removed to allow the safety to pushed out. This completes the disassembly. It is not recommended to disassemble the magazine.

The tab on the bottom must be straightened out and repetition of straightening and bending can work harden it until it breaks off.

To reassemble the rifle, first insert the action spring guide with springs. Then drop in the bolt and secure them with the bolt handle. Place in the ejector, then the magazine catch and its pivot pin. Secure them in place with the magazine catch spring. Reassemble the hammer assembly. The long end of the hammer pivot pin goes down. Hook the rear leg of the hammer pin onto the receiver shelf. Now put in the trigger pivot pin and the trigger.

With a dental pick, lift up the rear hammer spring arm and insert the hammer/trigger spring support pin. Now lift the remaining hammer spring arm over the hammer/ trigger spring support pin. Replace the receiver cover. Before the screw may be tightened, the cover must be aligned with the hammer pivot pin the trigger pivot pin. The most common complaint on these guns is failure to feed (jamming.) Check if the barrel nut is tight. A loose barrel nut affects both accuracy and reliability.

Second, rule out the ammunition by trying different brands or bullet types. Some .22s work better in some guns than others. Because the AR-7 is blowback operated, it should be used with high velocity .22 LR cartridges. The third thing is to clean the action thoroughly as the majority of all firearms malfunctions may be traced to dirty guns. While it is disassembled, check for burrs or anything that may impede the function of the bolt.

Some folks suggest chamfering the chamber but I don’t since doing so will eliminate any case support and make the gun more susceptible to case failure with the case blowing out into the action. The malfunction I have experienced most often with these guns were usually a three point jam. The top of the lead round nose would jam itself against the top of the chamber. The bottom of the lead round nose bullet would be jammed into the bottom of the chamber where a feed ramp would be in many other guns.

The bolt would press against the side of the case, and this will usually dent it. It was determined that the magazine’s bullet guide spring was not keeping the bullet nose low enough when the bolt was pushing the bullet forward. The bullet would porpoise up and then slam forward, jamming into the chamber. I have found an ideal cure for this is a 0.040" wire spring cut about three inches long and looped over on itself. Place the looped wire into a vise and bend it down with an eight-ounce hammer.

This is strictly a trial and error thing so don’t get frustrated if the first one doesn’t work. The bottom of the spring must then be bent 90 degrees to fit into the retaining hole. I placed the spring upside down in the vise with only the tip to be bent exposed. This was then hammered over. The end may flare out a bit, making it too big to fit into its hole in the magazine body, however, this is easily remedied by filing it round. When assembled, the spring must sit flush with the magazine.

If it doesn’t, it will rub against the magazine well and be difficult to insert or remove. The loop itself cannot be too long either or it will cause bolt drag. When assembled on the magazine, it should also be nestled behind the little feed lip of the magazine body. I had to bend mine slightly in to keep it from slipping past that finger. If it does that it won’t guide the bullet as well as it should.

The other problem was when the bolt recoiled, the magazine catch would bounce and release the magazine enough such that it would barely strip out a fresh bullet when the bolt went forward. Being far too low, it would jam again. If that didn’t happen the magazine would fall too low to feed. This was remedied by installing a slightly longer (and stiffer) spring of the same diameter. It is better to get too long of apiece and progressively shorten it than get a short spring that won’t work.

AG American Gunsmithing Association