The .22 Semi-Automatic is arguably one of John Browning’s most elegant designs, its balance and handiness is immediately apparent to anyone who has handled or shot one. In our latest video we examined the history behind the design and looked at its features in-depth. You can check out the video and full blog here.
Here are some additional photographs of the rifle:
This weekend I finally had the time to organise all of my photographs and video from my recent research trip to the US. The new 4TB back-up drive I ordered arrived so I could get copies of everything into one place and see what I have. In total it adds up for about 270gb of video and photos! I’m pleased to say tonight I started work on the first video that will come from the trip. I set about editing the photos of the weapon, these will be used in the video and the accompanying blog.
I’m excited to start editing video tomorrow but in the meantime I thought I’d share a few photos with you guys. I’m not going to give the game away and tell you just what this one is – but feel free to throw out some guesses. It’s a very interesting one!
Colt’s entry was perhaps the most conventional of the designs submitted. Based on the rifle the program sought to replace. Colt’s ACR was essentially an improved M16, which fired both conventional 5.56x45mm ammunition as well as a new 5.56mm duplex round. While the duplex round increase hit probability at shorter ranges, it impacted long range accuracy requiring the additional use of conventional M855 rounds.
It incorporated a variety of improvements including a new oil/spring hydraulic buffer to mitigate recoil. This resulted in a major decrease in the weapon’s recoil, Colt suggested as much as a 40% mitigation. A reshaped pistol grip and a hand guard which mounted a sighting rib for snap shooting – this stemmed from recommendations from the Human Engineering Lab. The weapon had a flat-top upper receiver which incorporated a weaver rail so a 3.5x optic (an early ECLAN) or a more conventional sight/carrying handle could be fitted.
The rifle’s collapsible six position telescopic butt stock was an improved version of that offered with Colt’s carbines. When at full extension the Colt ACR was the longest rifle tested, at 40.6 inch or 103 cm long. A distinctive proprietary muzzle brake compensator (MBC) designed by Knight’s Armament was also added. The Knight’s MBC reduced the rifle’s report by 13.5-decibels and also played an important role in recoil mitigation.
Colt’s duplex rounds were developed by the Olin Corporation and placed two projectiles nose to tail. The projectiles were copper jacketed steel penetrators. In theory the lead projectile would strike at point of aim while the second would strike somewhere near point of aim with in a theoretically limited area of dispersion. The forward round was 35gr while the second was slightly lighter at 33gr.
During testing one of the duplex rounds was not properly seated inside the cartridge case and when fired became lodged in the barrel and during the course of fire and the weapon’s barrel blew when another round was fired. This was addressed by a slightly larger propellant charge.
Another negative to the Colt entry was that, in addition to having to carry two types of 5.56mm ammunition, its duplex round offered no improvement in weight and was infact slightly heavier than standard M855 ammunition. While the hydraulic buffer, muzzle device and furniture were not used later, some of the features developed for the ACR entry were later employed in the M16A3 and later A4. These included the selector configuration and the flat-top upper receiver.
Specifications (From ACR Program Summary):
Length: 40.6 inches / 103cm (extended) and 36.7 inches / 93.2cm (collapsed)
Weight: 10.3 lbs / 4.67kg
Sights: iron or 3.5x optic
Action: Direct gas impingement
Calibre: 5.56mm duplex round & M855 ball
Feed: 30-round box magazine
You can find out overview article on the ACR program and all of the rifles here
Advanced Combat Rifle, Program Summary, Vol.1, ARDEC, 1992 (source)
‘Revisiting the SPIW Pt.3’, Small Arms Review, R. Blake Stevens, (source)
The Black Rifle II, C. Bartocci, (2004)
Our thanks to the collection that holds these wonderful examples of the ACR rifles
By the mid-1980s Steyr-Mannlicher were already leaders in unconventional small arms designs. In 1977 the Steyr AUG was adopted by the Austrian Army becoming the first generally adopted bullpup service rifle. As such Steyr-Mannlicher’s entry was inevitably a bullpup. Designed by Ulrich Zedrosser the rifle used a gas piston driven rising chamber mechanism which rose and fell to chamber rounds.
The rifle’s action is described in a 1988 patent (US #4949493) granted to Zedrosser, it explains that ” chamber member, which is separate from the barrel… is reciprocable between a firing position and a loading position in a direction which is transverse to the longitudinal direction of the barrel.” This means that the chamber rises and falls, with the rifle firing from an ‘open bolt’.
The patent goes on to explain the weapon’s action:
When the chamber member is in its loading position its chamber is freely accessible and at one end communicates through a loading opening of the firing block with the interior of a magazine holder and at the other end communicates through an ejection opening of the firing block with an ejection shaft. For the performance of the loading and unloading operation, a slider is provided, which is movable in the longitudinal direction of the barrel and carries a feeder, which is movable from a first end position… when the chamber member is in its loading position, and the movement of the chamber member from its loading position to its firing position is adapted to be initiated before the feeder reaches that end position in which the feeder extends into the loading opening.
One of the other patents (US #4817496) protecting the design explains the weapon’s gas system:
In order to provide a gas drive which is particularly simple and functionally reliable, light in weight and compact, the barrel is provided with a collar or the like, which constitutes a stationary pneumatic piston, and the pneumatic cylinder consists of a sliding sleeve, which surrounds the collar and is longitudinally displaceable between stops.
The Steyr ACR, like AAI’s entry, fires flechettes but Steyr’s are housed inside a cylindrical polymer case. The bullpup Steyr was the second shortest at 30 inches (76cm) and the lightest of the rifles submitted weighing 8.5 lbs (3.86kg).
The Steyr ACR borrows its ergonomics from its conventional forebearer, the AUG. With a moulded green plastic stock and a similar pistol grip, magazine release, trigger and safety layout. Unlike the AUG, however, the ACR uses an AR-15 style charging handle located at the rear of the sight mounting block and the stock extends further forward to encompass the barrel and gas system. The rifle could be fitted with a variable 1.5x to 3.5x optic or use iron sights.
As discussed earlier the rifle does not use a conventional bolt, instead it uses a rising chamber, as a result the rifle fired from an open bolt. A live round only entered the chamber after the trigger had been pulled, thus reducing the potential for cook-offs. Spent polymer cases were pushed out of the chamber and ejected from an opening just in front of the magazine well.
Feeding from a 24-round box magazine, made from the same translucent material used in conventional AUG magazines. The magazine goes from double stack to single stack, to allow it to feed reliably, as a result the capacity had to be shortened. A high capacity drum magazine was planned but not provided for the trials. The polymer case held a fin stabilised 9.85 gr flechette with a moulded four piece sabot which broke up soon after exiting the muzzle. This was identified as a shortcoming as it risked hitting nearby troops.
ACR Program Summary recognised the Steyr ACR entry as “the simplest weapon, the simplest round, and the most cost effective approach of any of the ACR contenders.” The report noted that the weapon’s “greatest current deficiency is its poor round to round dispersion characteristics.” This was a criticism levelled at both the flechette firing entries, it essentially ended the US Army’s interest in flechette firing individual weapons, relegating the concept to larger area effect weapon systems.
In our latest video we take a look at the massive 15 Inch Coastal Guns that protect the port of Mahon in Menorca. The guns, built by the British Vickers company, could fire an 860kg shell up to 35km.
The battery of two 15 or 381mm guns was added to the Fortalesa Isabel II’s emplacements in the early 1930s and were in active service for nearly 80 years. For more information on their history and design, check out the video and full in-depth blog here.
Below are some photographs I took of the battery and its ancillary support buildings. While researching I also found a couple of great contemporary photos.
A facebook group for those who served at Fortales Isabel II has a number of brilliant contemporary photographs of the guns:
These photographs show the guns being transported by a specially laid, segmented rail track in the early 1932s, the first shows the guns at the dockside with another showing it being moved through a busy street.
The group also has some contemporary photographs of the gun emplacements including the rangefinder and the inside of the gun housing:
The gun aimer’s position with communications to the rangefinder bunkers near by:
The group also has some excellent recent photos of the restored interior of the gun turret the magazine below. The first photos show the magazine and system for bringing the 860kg shells up from the projectile store:
Sign reads: ‘Ordinary projectiles will only be used with reduced load‘
Great shot of the various tracks, winches and lifts used to get the massive shells up to the turret:
Interior shot of the turret with a shell ready to be winched onto the loading tray and loaded into the breech:
View of the gun aimer’s positions complete with shining brass speaking tubes and controls:
During our first research trip last spring I had the opportunity to examine an unusual ‘hybrid’ Sten submachine gun. The weapon combined a MkII Sten’s receiver with a MkIII’s magazine housing. Added to this was a proprietary folding stock and a new fire control group and pistol grip.
Very little is known about the hybrid Sten with Peter Laidler’s book The Sten Machine Carbine mentioning it and the later Osprey book by Leroy Thompson sharing a photograph and brief caption which calls it an “experimental version of the Mk III.” It is also unclear exactly when it was built.
Below are some photographs I took of the Sten, lets look at some of the interesting features of the Hybrid Sten.
No production Variant of the Sten was fitted with an under-folding stock, the Australian Austen, however, directly copied the MP38/40. The entire weapon is covered by a layer of textured, crackle paint finish, this was commonly used on commercial Sterling Mk4 submachine guns. The weapon has a short, 3.5 inch, perforated fore-end welded onto the front of the tube receiver that appears to be from a Lanchester.
The under folding stock is rudimentary but effective, the butt plate swivels free but the lock up is quite secure. It uses the receiver main spring-loaded return-spring cap. The folding stock attaches to the pistol grip assembly (which can be seen detached below).
The proprietary rectangular trigger group housing brazed onto the tub receiver is unlike any other Sten and lacks a fire-selector.
The pistol grip itself is made from paxoline, a form of early resin plastic. The shape shape of the pistol grip does not resemble any production or prototype Sten grip. A simple hand-stop, made from a bent piece of sheet metal, has also been added in front of the weapon’s ejection port to prevent the user’s hand moving back and fingers being caught if gripped by the forend.
While the origins of the hybrid Sten remain unclear I don’t believe it was an officially made prototype. While impressive it is relatively crudely assembled and does not match the Sten prototypes made by Enfield, such as the VI. Intriguingly, the magazine housing of the weapon has been stamped ‘PILOT’ below the usual ‘STEN MkIII’ stamp. I suspect that the weapon may have been put together by a unit armourer, perhaps authorised by a superior officer to suggest improvements or as an unofficial project gun.
UPDATE: Their is some evidence emerging that this Hybrid Sten may be related to the T42 Sten prototype, part of the Sten MkIV development program. Where this hybrid fits into the story is not yet clear but the similarities are striking, when we have more information we will revisit this weapon.
In the first part of Vic’s special episode on the AR-10 we brought you a remastered version of the fascinating 1958 ArmaLite/Fairchild promotional sales film made for ArmaLite salesmen, like Sam Cummings and Jacques Michault, to show to prospective buyers of the new rifle. Back in the 1990s Vic was lucky enough to scan Michault’s copy the film and has recently remastered with better image quality.
Below you can find the video, time stamped to begin at the promotional film (although I highly recommend you watch the entire video for Vic’s introduction to the early history of the AR-10).
Lets break the video down, with the help of some screen captures. The film opens with a rifleman emerging from the sea, firing as he advances. The film then explains Fairchild’s background and beings to explain the features of the rifle.
The film then shows several shots of the rifle’s lower receiver being milled.
None other than the rifle’s designer himself, Eugene Stoner, then takes an AR-10 from a wall display and proceeds to completely disassemble it.
Stoner completely strips the rifle, its muzzle device and its magazine before Charles Dorchester, ArmaLite’s production manager, demonstrating the rifle’s operation and subjects it to sub-zero temperatures and once again firing the rifle.
Chuck Dorchester submerges he rifle in what appears to be liquid nitrogen
Dorchester again test fires the rifle
The film then shows the rifle being used in a variety of roles:
Stoner then covers the rifle with sand before running five magazines through the rifle in quick succession to demonstrate reliability:
The rifle is then submerged in mud (with its dust cover closed) and demonstrated again.
The film then shows how simple field stripping and cleaning is before Stoner demonstrates the belt-fed variant of the rifle:
Don’t forget to check out the full episode and the accompanying blog here!