AR - 7 The ArmaLite AR - 7 Explorer , designed by M - 16 inventor Eugene Stoner , is a semi - automatic . 22 Long Rifle rifle developed from the AR - 5 adopted by the U . S . Air Force as a pilot and aircrew survival weapon . Its intended markets today are backpackers and other recreational users as a takedown utility rifle . The AR - 7 is often recommended by outdoor users of recreational vehicles ( automobile , airplane or boat ) who might have need for a weapon for foraging or defense in a wilderness emergency . History & design . The prototype of what would become the AR - 7 was designed by Eugene Stoner at ArmaLite Inc . , a division of Fairchild Aircraft . The rifle shares some of the features of the bolt - action AR - 5 , another rifle designed by Stoner for ArmaLite and adopted by the United States Air Force in 1956 as the MA - 1 . The MA - 1 was intended to replace the M4 Survival Rifle and the M6 Aircrew Survival Weapon which was a superimposed ( " over - under " ) twin - barrel rifle / shotgun chambered in . 22 Hornet and . 410 bore , using a break - open action . The AR - 5 had the advantage of repeat fire over the then - standard M6 , using the same . 22 Hornet cartridge . When the AR - 5 was adopted as the MA - 1 but was not placed in issue due to the numbers of M4 and M6 survival weapons in USAF inventory , ArmaLite used the research and tooling for the AR - 5 in developing the AR - 7 for the civilian market . The AR - 7 uses a blowback semi - automatic action in . 22 Long Rifle but retains the AR - 5 / MA - 1 feature of storing the disassembled parts within the hollow stock , which is filled with plastic foam and capable of floating . Like the bolt - action AR - 5 , the AR - 7 was designed as a survival rifle for foraging small game for food . The AR - 7 is constructed primarily of aluminum , with plastic for the stock and buttcap . Even the barrel is aluminum ( in later production composite material ) , using a rifled steel barrel liner . The AR - 7 measures 35 inches overall when assembled . It disassembles to four sections ( barrel , action , stock , and magazine ) , with three parts storing inside the plastic stock , measuring 16 inches long . The rifle weighs 2 . 5 pounds light enough for convenient backpacking . The rear sight is a peep sight , which comes on a flat metal blade with an aperture ( in later production two different size apertures ) , and is adjustable for elevation ( up - down ) . The front sight is adjustable for windage ( side - to - side ) . Accuracy is sufficient for hunting small game at ranges to 50 yards . Criticisms . Reliability of the AR - 7 is highly dependent on the condition of the magazine and on the ammunition used , perhaps more so than with other models of semi - automatic . 22 caliber rifles . The feed ramp is part of the magazine and subject to damage from mishandling . Flat - nosed bullets tend to jam on the edge of the chamber of the barrel . The transition of cartridge from magazine to barrel can be smoothed by minor beveling of the chamber of the barrel , by using round - nosed as opposed to flat - nosed bullets and by paying attention to condition of the feed lips and feed ramp of the magazine . Later production magazines include an external wire spring to align the cartridge ; earlier magazines used two pinch marks at the top of the magazine body , which could become worn over time . All iterations of the AR - 7 from the Armalite to the Henry U . S . Survival rifle use a bolt and dual recoil springs that are heavy compared to most other . 22 semiautomatics . The AR - 7 requires high velocity ammunition for reliable functioning . The manufacturer recommends use of 40 grain round nose bullets in high velocity loadings . It is still possible to manually load a single round into the firing chamber , allowing use of flat nosed bullets or low velocity or subsonic ammunition . The barrel takedown nut tends to loosen after firing and may need hand - tightening to maintain both accuracy and reliability . Armalite sold the design to Charter Arms in 1973 . According to some accounts posted by enthusiasts , this is where quality began to deteriorate . Barrels were said to have a tendency to warp . Other sources state that the first production at Charter had problems which were corrected in later production runs . Since Charter Arms sold the design and rights to Henry Repeating Arms in 1980 , the Henry AR - 7 has regained a reputation for reliability . Production history . " ( Summary of information available in The Blue Book of Gun Values ) " AR - 7 variants . Armalite AR - 7 Explorer . Armalite barrels had a steel liner in an aluminum shell . The Armalite stock did not accept the receiver with a magazine in place and the gun was normally sold with one magazine . The receiver did not provide for a scope mount . The rear sight was a peep aperture , adjustable for elevation . The front sight was drift - adjustable for windage . Argentine variant . The AR - 7 was also manufactured in Argentina . It came with various barrel lengths , shrouds and fixed rifle stocks as well as pistol grips with retractable stocks . Herter ' s Outdoor Supply . Herter ' s , Hy Hunter and American International Distributors marketed . 22 replicas of the Broomhandle Mauser ( Bolomauser ) , Thompson Submachine Gun ( T - 62 Civilian Defense Model ) and M1 Carbine made on AR - 7 receivers and barrels . Charter Arms AR - 7 Explorer . The Charter Arms AR - 7 Explorer rifle basically replicated the Armalite AR - 7 Explorer with variations in finish . Charter Arms Explorer II pistol . Explorer II was a pistol version of the AR - 7 . It resembled a Broomhandle Mauser . The receiver had a built - in pistol grip with no provision for the rifle stock ( the internal parts are interchangeable between rifle and pistol ) . The rear sight of the pistol was an open notch adjustable for windage and elevation . The Explorer II front sight was integral with the barrel shell and was not adjustable . The magazine well in front of the trigger guard would accept any magazine designed for the rifle . A spare 8 round magazine could be carried inside the grip . The most common barrel was six inches . Optional barrel lengths included eight and ten inches . Legal note . Due to the U . S . 1934 NFA regulations setting minimum rifle barrel length at 16 inches , Charter Arms made the barrels of the Explorer I rifle and Explorer II pistol non - interchangeable to prevent users from installing the pistol barrel on the rifle . The AR - 7 barrel has an alignment lug that mates a notch in the receiver . The rifle receiver notch and barrel lug are on top ; the pistol notch and lug are broader and on the bottom . If a Charter Arms factory - made pistol barrel were installed on a rifle , the extractor on the bolt would be opposite the extractor slot in the barrel , preventing the bolt from closing ( plus the front sight would be upside down ) . Modifying the pistol barrel to fit the rifle , or modifying the rifle receiver to accept the pistol barrel , would legally be " making a short barrel rifle " requiring federal registration on an ATF Form 1 with payment of a $ 200 . 00 tax . AR - 7 Industries . AR - 7 Industries made solid steel barrels much heavier than the AR - 7 barrels by Armalite , Charter or Henry . Henry Survival Rifle . In 1980 , the design and production rights passed on to Henry Repeating Arms and the compact rifle was slightly revised . The AR - 7 is now ( 2011 ) known as the Henry U . S . Survival rifle . An ABS material replaced the original plastic , which was prone to cracking and failure . The receiver recess in the Henry stock allows storage of receiver with a magazine in place and the rifle is normally sold with two magazines . The latest versions of the Henry allow for storage of three magazines total , with two in the stock recess , and one in the receiver . The modern Henry U . S . Survival rifle is also waterproof ( all prior versions were known to leak water inside the stock ) . They now include a full teflon coating on the outer surface . A 3 / 8 in . rail milled into the top of the receiver for mounting a wide variety of optics is now a standard . Israeli pilot ' s survival rifle . Another variant was made by Armalite and sold to the Israeli Military for use as pilot / aircrew survival weapons . The Israelis further modified these rifles , adding a telescoping stock , a pistol grip from a FAL - type rifle , shortening the barrel ( to 13 . 5 inches ) , and adding a front sight based on the K98k Mauser . After Israeli service , some of these rifle were re - imported into the U . S . by Bricklee Trading Company ( the barrels are marked with the BTC identification as required by U . S . laws on imported guns ) for sale on the civilian market , and command a premium among collectors . In order to comply with U . S . Federal law , a 3 inch muzzle brake had to be permanently attached in order to meet the minimum 16 inch barrel requirement . Operation . The AR - 7 functions as a simple or plain blowback semi - automatic . The AR - 7 is a light firearm with heavy bolt and twin recoil springs and must be firmly held for reliable blowback operation . Range safety issue . As is common with many blowback . 22 rifles , the AR - 7 bolt cannot be locked open to demonstrate the weapon is in a safe unloaded state . Firearms without a built - in " bolt hold - open " device may be banned from use at some ranges . Other firing range operators allow use of an open bolt indicator to prop the bolt open so that the chamber is visible . The yellow plastic flag for CMP range use is recommended or a spent cartridge case can be used . Aftermarket modifications . The fact that both the barrel and stock are detachable has led to a plethora of after - market accessories , similar to those available for the Ruger 10 / 22 . Barrels , stocks , and grips , of varying finishes and utility , can be added to the rifle . These include collapsible stocks , wire - framed stocks , pistol grips , flash suppressors , shrouded barrels , high - capacity magazines , telescopic sights , reflex ' red dot ' sights and other occasionally fanciful - looking hardware , usually at a cost greater than the rifle . Such accessories usually make it impossible to use the original floating stock for storage of modified parts . The Henry U . S . Survival AR - 7 has a 3 / 8 " rail integral with the receiver . For earlier makes , B Square supplied the Charter Arms AR - 7 Explorer Scope Mount , an accessory bracket with a 3 / 8 " rail to accept tip - off scope rings . The scope mount attached by the receiver side plate screw ( the Charter Arms side plate screw is longer than that of the Armalite ) . This scope mount can be used on the Armalite and the Charter Arms Explorer rifle and Explorer II pistol . However , with the bracket in place , the rifle receiver will no longer fit the recess in the stock for storage . ( The bracket is not needed on the Henry version and will not fit . ) A complaint sometimes heard about the AR - 7 is its lack of a sling , apart from the highly modified Israeli models , although some users have attached slings that do not require modification to the rifle for use . A 20 gauge shotgun sling swivel meant to clamp to the magazine of a 20 gauge shotgun and a universal sling work well for this purpose . An appropriate length of parachute cord with a slip knot at either end makes a usable lanyard , given the light weight of the AR - 7 .