Boys anti-tank rifle 
The Rifle, Anti-tank, 0.55-in, Boys, Mk 1 was originally known as the Stanchion Gun, but the name was later changed to honour the name of its principle designer after he died just before the weapon entered service. It was designed to be the standard infantry antitank weapon of the British army, but it was soon overtaken by events and had only a short active career, The first of the type entered service during the late 1930s and by 1942 the weapon was obsolete, overtaken by rapid increases
in enemy tank armour that the Boys rifle could no longer tackle.
the 14 x 99B cartrigde. (
MUNICION.ORG)
The Boys anti-tank rifle had a calibre of 13.97mm (0.55 in) and fired a powerful cartridge that could penetrate 21mm (0.827 in) at 302m (330 yards). The cartridge produced an equally powerful recoil, and this didlittle to endear the weapon to its firer, To reduce this recoil somewhat the long slender barrel was fitted with a muzzle brake.
Ammunition was fed into the bolt-action firing mechanism from an overhead five-round box magazine. Overall the Boys was rather long and heavy, which made it an awkward
load to carry, so it was often mounted as the main weapon on board.
A French officer is about to receive
the hefty recoil from a Boys anti-tank
rifle. The French army used a
number of these rifles in 1940 
Bren Gun or Universal Carriers. More were used as the main armament of
some light armoured cars. The first production Boys used a forward-mounted monopod combined with a handgrip under the butt plate. After Dunkirk various modifications were made to speed production, and among the measures taken was replacement of the forward monopod by a Bren Gun bipod and of the circular muzzle brake attachment ba new Solothurn muzzle brake with holes drilled along the sides; this latter
was easier to produce than the original.
Mk I with simplified Muzzle brake. 
In this form the Boys saw out its short service life, as by late 1940 it was regarded
as being of only limited use as an anti-armour weapon. Eventually it was replaced by the PIAT, but before
it finally departed it had a brief flurry of popularity during the Entrean and
Cyrenaica campaigns of 1940 and 1941.
Boys in use by U.S.M.C soldiers. 
It was found to be a very effective anti-personnel weapon during these campaigns as it could be fired at rocks
over or near a concealed enemy, the resultant rock splinters acting as effective anti-personnel fragments, The Boys also found its way into US Marine Corps hands during the Philippines campaign of early 1942, when some
were used very sparingly against dugin Japanese infantry positions. How
these Boys rifles got to the Far East is not recorded. Also the british commandos used the Boys to knock out Flak emplacements in the Dieppe landings.
Some captured Boys
anti-tank rifles were also used by the Germans for a short while after Dunkirk,
but only in limited numbers; the
type was known as the
13.9-mm Panzerbüchse 782(e). Bren carrier with Boys, Kursk July 1943. 
In 1940 there were plans to produce a Mk 2 version of the Boys. This would
have been a shortened and lightened version for use by airborne forces but
it did not get very far before the project was terminated, no doubt because
the shortened barrel would have produced an even more violent recoil.
Specification Boys Mk 1
Calibre: 13,97 mm (0.55 in)
Lengths: overall 1.625 m (5 ft 4 in);
Barrel 0.914 m (36 ft 0 in)
Weight: 16.33 kg (36 lb)
Muzzle velocity: 790 m/s AP, 810 m/s APC, 884 m/s APCR
Armour penetration: (APC) 21 mm (0,827 in) @ 302 m (330 yards)
Antitank Rifles and MGs. 1930-1945. 
Thanks that is just my stile.
Linear Mode
