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 willyp | Home > Weapons of the world photo Albums > US Colt/Armalite AR15/M16 (5.56) > 
Colt Model 603 (XM16E1, M16A1 Army)
After the "trial" of the 601 the Army requested a number of mods, mainly the addition of the forward assist to the upper receiver, this is the Model 603 which became the XM16E1 in 1964, as more modifications were made & needed they were added during the production runs & resulted in the type being "type standard" by the Army as the M16A1 in 1967. Shown in the album here are replicas of an early 65-67 XM16E1, a 71 era M16A1, an early build of a late M16a1 w/an A2 lower (to be replaced) w/a starlight scope & a rebuild A1 86-94.
Album by willyp. Photos by willyp. 1 - 68 of 68 Total. 40248 Visits.
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Enlarge photo 1

XM16E1 65-66 era & accs
The rifle shown is built to represent a Model 603/XM16E1 from 64-67 production, these were the first models w/the US Army requested Forward Assist. These rifles were built beginning in 1964-65 up to 1969 when they were supplemented by the "finalized" Model 603/M16A1.

Enlarge photo 2

The XM16E1 is shown with 2 universal pouches, 1 early (w/grommet in strap), 1 later w/o grommet, these pouches were used w/the M14 & were carried over for use w/the M16 in VietNam, also shown is the bipod & it's XM3 pouch & the standard M7 bayonet (this particular one being BOC mfg) & it's M8A1 scabbard.

Enlarge photo 3

XM16E1 w/bayonet mounted
This rifle is an early example & is fitted w/all early parts, chrome bolt group w/FA serrations, machined firing pin retainer, original large head firing pin, early gas tube, forged/smoothed front sight base w/no drain hole, MP mkd 1/12 barrel, "dimpled" takedown/pivot pins, selector, mag release, mid "many circle" mag button, 2nd style bolt release latch, early buffer tube modified w/wrench flats added, original Edgewater buffer, "mottled" handguards, buttstock & grip, early .223 mkd 20rd mag w/alloy follower & early issue cotton web sling.

Enlarge photo 4

XM16E1 open w/bolt
Basic field strip configuration for cleaning w/bolt removed. Note the bolt group is all chrome which was later modified to a parkerized bolt, then a full parked bolt & carrier, also the 2nd pattern flash suppressor.

Enlarge photo 5

XM16E1 R Bolt group right view
Note the carrier key at the top which has a round profile, later they were square in profile.

Enlarge photo 6

XM16E1 L Bolt group left side
Here you can see the early style firing pin retainer, the small chrome circle about mid way just under the rear of the carrier key, this was later changed to a much simpler retainer that resembles a small cotter pin.

Enlarge photo 7

XM16E1 R Buttplate
Early XM16E1's utilized the type C buttstock which was black, had a moveable swivel which was rubber coated, a flat solid buttplate (w/no door), the small screw at top held the buttstock to the rifle by screwing into the rear of the receiver extension/buffer tube. Early on these screws had no hole (what should & will be on this rifle soon), the later screws, shown here had a small hole in the center for drainage,

Enlarge photo 8

XM16E1 buttstock
This particular example has a minor "mottled" appearance w/bits of brown in it, most are a full black.

Enlarge photo 9

XM16E1 Recvr xtension/buffer tube
The head of the early Edgewater buffer (which is round) can be seen here, the later buffer had a slightly hex shape, the early buffers were replaced w/the later style due to cycling problems. Also you can see the small hole at the rear for a roll pin which secured the buffer tube on early M16's & M16E1's, this hole was not present on late XM16E1's or any of the M16A1's, also note the dimpled takedown pin & selector shaft.

Enlarge photo 10

XM16E1 right action
Here you can see the added forward assist w/teardrop button which began w/the 603/XM16E1, early style XM16E1 receiver w/hole for pin to retain receiver extension, early dimpled pins, the "partial fence" over the mag well which served to give some protection to the mag release button & also held the detent & spring for the front pivot pin, the earlier models, 601/602 did not have the detent & the pivot pin could easily be lost while cleaning.

Enlarge photo 11

XM16E1 w/ejection port door open
Same view showing the ejection door open w/the bolt group in view.

Enlarge photo 12

XM16E1 mag floorplate
Here you can see the markings on the floorplate on a Colt mag, early mags were marked .223, to approximately 69-70, 5.56 after.

Enlarge photo 13

XM16E1 mag button "interim"
Early 601/602 used a mag button w/horizontal serrations, replaced w/the semi-circular style, this one is another variant believed to be a very early variant of the semi-circular style, referred to as "many circles".

Enlarge photo 14

XM16E1 forend
Mottled black triangular style handguards, also note the early style retaining ring at the rear, these were flat in profile.

Enlarge photo 15

Gas tubes, early-late
Top: early style
Bottom: later style
The early style was made of carbon steel & had a different 'bend" to it, they were used to approximately 1967 as far as I know. The later style replaced the early after that & was stainless steel w/a different bend. The top one above is on the 65-66 XM16E1, the bottom is on the 80's era M16A1 shown later in the album.

Enlarge photo 16

XM16E1 sight base
Early 601's used a 1/14 barrel, later a 1/12, the barrel on this rifle is a 1/12, 65-66 era marked w/MP (magnetic particle tested) under base, these barrels had no chrome bore or chamber lining. Model 601/early 602/very early XM16E1's used a cast front sight base, which was smooth & had raised lettering on the top w/no drain hole under the front sight post, next variant (shown here) was forged, then smoothed, had embossed lettering on top & no drain hole.

Enlarge photo 17

XM16E1 front sight base & muzzle
Another view of the 2nd style front sight base, these also had no markings (other than the pre-mentioned sight mkgs on top), also shown is the 2nd model flash suppressor, the 601 used a similiar earlier style, known as the "duckbill", it had 3 prongs but was straight in profile, it was improved by turning the profile "in" on the 2nd, these were eventually replaced by the 3rd style, "birdcage" shown on the A1 later in the album.

Enlarge photo 18

XM16E1 muzzle w/bayonet mounted

Enlarge photo 19

XM16E1 bayonet mounted left view

Enlarge photo 20

Gas tubes, early late
Top: early
Bottom: late

Enlarge photo 21

XM16E1 left side forend

Enlarge photo 22

XM16E1 interim bolt release
Original 601 type bolt release had a serrated flat at the bottom, the next style (shown here) added a small extension at the bottom but still had the serrations on the angle, the next (& still current) style has no serrations on the angle.

Enlarge photo 23

XM16E1 left action
Early features, dimpled pins, selector lever, interim bolt release which were soon replaced w/the later styles seen on the M16A1 in this album. There appears to be no firm cutoff date for most of these differences but they can be found even late into XM16E1 production in conjuction w/later parts! Note also the lower receiver which is mfg by NoDakSpud, it is a replica of the "partial fence" lower & is a beautiful piece of work, they also mfg replica's of the 601/M16, M16A1 "full fence", early experimental upper w/charging handle under the handle & the M16A2! A true replica retro M16 would be very difficult w/o NoDak, my thanks go out to them!

Enlarge photo 24

XM16E1 left buttstock

Enlarge photo 25

XM16E1 left side bayonet mounted

Enlarge photo 26

Late 70's era M16A1
In 1967 the Army adopted the XM16E1 as standard as the M16A1, additional changes were the full fence lower, later buffer & tube (which were actually adopted on the XM in 12/66), "birdcage" closed flash suppressor (although the cage could be found on XM16E1's & the 2nd style 3 prong could also be found on A1's), early A1's started w/chrome lined chambers, then bores were also chromed by 68-69.

Enlarge photo 27

M16A1 upper forge code marking
Until approximately 1970 upper receivers only had C & diamond stamping in front of the ejection port, around this time due to major production increases Colt started getting receiver forgings from contractors, these were marked under the rear sight wheel w/a forge code, in this case C M.

Enlarge photo 28

A1 upper w/Starlight scope mount
Here you can see the full fence which now "surrounds" the mag button & most of the later parts, non-dimpled pins & selector, also note there is no hole at the very rear of the receiver extension for the roll pin for the buffer tube. The receiver shown on this rifle is actually an A2 w/reinforced areas at the receiver xtension in the rear & the pivot pin holes in front. This rifle is also shown w/the mount for the AN/PVS2 "starlight" NV scope.

Enlarge photo 29

Early/late gas tube comparison
Top: early (on XM16E1)
Bottom: late (on M16A1)
This is a view of the right side.

Enlarge photo 30

Left view of the A1 muzzle

Enlarge photo 31

Left view of the early/late gas tubes
Top: early tube
Bottom: later tube

Enlarge photo 32

A1 handguards, left side
The guards on this rifle are a more uniform black w/no mottling or speckling as seen in the XM16E1
pics, this is not indicative of an XM or A1 though, it's only thought the "mottled" furniture may be earlier.

Enlarge photo 33

Left view of the A1 action w/NV scope mount
Here you can see the offset position the mount style creates w/the NV scope, off to the left, it's actually possible to use a normal cheek weld when shooting w/the scope if you use your left eye to sight, just have to zero the scope using the left eye if you're going to do it that way!

Enlarge photo 34

Top view of the NV mount
The mount is actually easy to attach, there's a small seperate tab behind the thumb screw shown, you slide the mount (w/this tab removed) under the handle, set the tab on the left side against the handle, place the seperate/removeable tab in place & tighten it on w/the thumbscrew, the front of the mount is fitted to the curve at the front of the upper & sits very solidly in place.

Enlarge photo 35

Top view of NV mount attached
Here you can see the head of the bolt on 1 side & the thumbscrew that attaches & locks the mount to the carry handle, also you can get a better idea of the offset position the NV scope sits.

Enlarge photo 36

M16A1 left view of action
Here you can see the rail on the mount, the NV scope slides on from the rear & 2 lock tabs are turned which secure it to the rail.

Enlarge photo 37

A1 buttstock left
The stock for the A1 (type E), has a removeable buttpad w/a trap door, there's a hollow area under the door for storing a cleaning kit, this buttstock also uses a fixed, non-moveable swivel which is held in place by a screw through the buttpad instead of a roll pin like the earlier stocks, also the swivel is not rubber coated.

Enlarge photo 38

M16A1 w/NV mount left view

Enlarge photo 39

M16A1 w/AN/PVS2 starlight scope
Here the rifle is fitted w/the NV scope. This scope is the AN/PVS2 starlight, a passive system which amplifies the available light (moonlight, starlight, etc) & was much harder to detect then the earlier IR (infrared), an active system which emitted an IR light source & was easily detectable.

Enlarge photo 40

Quarter view w/the NV scope
Here you can get an idea of the offset of the scope. Also note the large filter on the front lens which had to be on if the scope was to be used in light, too much light would trigger the set to shut down to avoid burning out the intensifier unit. This is a first generation NV set, was the second in the line of, AN/PVS1, AN/PVS2, AN/PNVS3, & AN/PVS4.

Enlarge photo 41

Quarter rear view of the scope set
The rifle w/scope is a bit bulky & heavy, the PVS2 weighs approximately 7Lbs bt is actually a bit shorter & lighter than the earlier PVS1 by about 3" & 2Lbs, the PVS3 was quite a bit smaller & lighter but was only used very late in VN, the 1&2 saw service starting about 1966.

Enlarge photo 42

Left view w/NVscope
Round cap at rear of upper portion of the scope is the battery compartment.

Enlarge photo 43

Another view from the front.
You can see the 2 locking screws at the very bottom of the mount, the square section at bottom of the scope was actually where the scope is adjusted to zero the rifle.

Enlarge photo 44

Left rear view

Enlarge photo 45

Top of the M16A1 w/ AN/PVS2 mounted
Probably the best view to get an idea of the offset position of the scope when mounted.

Enlarge photo 46

Left side view w/NV

Enlarge photo 47

Late A1 R w-M7

Enlarge photo 48

Rebuild A1, 1986-94
This rifle is a replica of a rebuilt A1 (1984-1992), it has a late CH code upper w/the cartridge deflector that was standardized on the A2, the late A1 large round forward assist, is fitted w/the late 70's early 90's night sights & the later black nylon m1 style sling & an A2 port door.

Enlarge photo 49

Lg round FA & cartridge deflector
Here you can see the earliest round FA button, which is large diameter (5 "rings"), the cartridge deflector, & the A2 style port door w/the lg square "bumper".

Enlarge photo 50

Late A1 forge code
Late CH coded upper w/cartridge deflector.

Enlarge photo 51

Late A1 right action view
This rifle is fitted w/a C MP Chrome Bore mkd barrel, forged sight base w/flashing.

Enlarge photo 52

Lg aperture rear night sight

Enlarge photo 53

A1 handguard left side

Enlarge photo 54

Front night sight
You can see here the later style front sight base w/flash molding left on, the front sight post is one of the fairly rare night sight models which has a dot on top & down the sights, these were composed of a mildly radioactive luminescent material.

Enlarge photo 55

Late A1 R mzzl w-M7 bay

Enlarge photo 56

M16A1 muzzle
This view shows some minor later parts variations, the front swivel is held on by a rivet instead of the earlier roll pin (app. 1970-1971), the front sight base is forged but is not smoothed any longer it retains it's forging flash & there is a drain hole added under the front sight post, the base is also marked w/a C & a bell, the earlier bases were unmarked, this rifle has the Chrome chamber & bore, marked C MP Chrome Bore on barrel, this marking started app 1974, earlier (app 69-74) Chrome bore barrels were mkd C MP B, earlier barrels w/only chrome chambers were marked C MP C, and a better view of the "closed" birdcage suppressor.

Enlarge photo 57

Late A1 L mzzl1

Enlarge photo 58

Late A1 L forend1

Enlarge photo 59

Late rebuild A1 left action view
Details on this side are the same as the earlier A1 models.

Enlarge photo 60

Late A1 L Butt1

Enlarge photo 61

Late A1 buttplate

Enlarge photo 62

Late rebuild A1 left view

Enlarge photo 63

late A1 & Cobray 37mm flare launcher
The following are pics of the above rifle fitted w/original USGI M203 launcher sights & handguard & fitted (for now) w/a 37mm Cobray flare launcher. The launcher approximates the "look" of the M203 but is far away in detail.

Enlarge photo 64

late A1 M203 quadrant sight left
Here is a pic fitted w/the M203 rear quadrant sight which mounts to the carry handle, the attachment screw can be seen.

Enlarge photo 65

Late a1 & Cobray launcher
The handguard & front leaf sight are USGI M203 parts, the 37mm flare launcher is mounted under the barrel in the same manner as the real M203 but sits substantially lower than the M203, this is a very unweildy & uncomfortable setup, not sure how it compares to an actual M203.

Enlarge photo 66

Left side of w/the Cobray mounted
The actual M203 used the front leaf sight on top of the handguard for shorter range use, the carry-handle mounted quadrant sight was used for longer ranges.

Enlarge photo 67

Late A1 M203 quadrant sight
Close-up view of the quadrant sight, the sight "pins" are on mounts that swivel out to the left for use (they're folded here). I may try to fit an airsoft M203 (which are much more "accurate" in appearance than the flare launcher) to get at least a cosmetic match for an M203 equipped M16A1.

Enlarge photo 68

Left view w/the flare launcher mounted

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