Back (Anti-Tank Projectiles)

Browning, Boys and Solothurn Anti-Tank Weapons

Anti-Tank Rounds In the years after the Armistice of WWI, most arms designers worked under the assumption that the next war would be fought much the same as the last. Few anticipated the advancements in tank technology during the next 20 short years which resulted in a surprisingly dominate and mobile force on the modern battlefield.
It is ironic that forward thinking anti-tank rifle development produced a variety of finely engineered weapons optimized for an outmoded form of warfare.

Left to Right:  
Boys .55cal w/5-round stripper clip & ammo pouch
Solothurn 20mm x 105B, AP-HE-T (Hungarian)
Browning .50cal w/ metal link belt

Boys ATR Boys .55 cal (14mm) Anti-Tank Rifle
Barrel Length: 36" (915mm)
Weight: 36lb (16.3kg) unloaded
Muzzle Velocity: 3250 fps (990m/s)
Penetration: 21mm (.83") @ 300m (328yds)

The British decided on a straight forward approach for their anti-tank rifle solution with a magazine fed (5-round) bolt action rifle, firing a high velocity steel core AP round.
It was adopted in 1937 and issued to troops in the Pacific and later U.S. Marines and Army, where it was effective against Japanese tanks, but of limited practical use.

The Boys was also provided to the Finns for the "Winter War" of 1939 in Europe. It was reported that it was "adequately effective" against the Russian T-26, provided the "soft" points of the tank were hit.
By 1942 the Boys was ineffective and of no practical value and was replaced by the P.I.A.T..

Browning .50cal Machine Gun
Browning .50cal (12.7mm) M2-HB
Heavy Machine Gun

Barrel Length: 45" (1143mm)
Weight: 81 lbs (+44 with tripod) (37+20kg)
Muzzle Velocity: 2800 fps (853m/s) @500 rpm
Penetration: 7/8" (22mm) @ 100yds

American designers, took a different approach to an infantry anti-tank design, choosing the machine gun rather than rifle or cannon. Tanks had been defeated in WWI by concentrated .30cal machine gun fire, so they improved on the German 13mm rifle cartridge and developed a belt-fed machine gun to fire it. A machine gun would also be useful for anti-aircraft use. A variety of ammunition types were also developed.

While never fulfilling it's anti-tank role, it was found to be a superior weapon against lightly armored vehicles, aircraft, installations and infantry. The "50" ended up being used on the ground, in the air and on the sea and became one of the most versatile and successful weapons designs of the 20th century.

Swiss Solothurn, S-18/100 20mm Anti-Tank Cannon
(Manufactured for export and adopted by Italy, Hungary, and Switzerland.)
Finnish, L-39 Lahti 20mm Anti-Tank Cannon 

Solothurn 20mm
Finnish Lahti

System of operation: Recoil, semi-automatic, rotating bolt
Overall Length: 85 in
Barrel: 57 in
Weight: ?
Feed Device: 5 or 10-round box magazine
Muzzle velocity: 762 m/sec
Penetration: 35mm at 300m
System of operation: Recoil, semi-automatic
Overall Length: 2 240 mm ( 88.2 in )
Barrel length: 1300 mm ( 51.2 in )
Weight: 49.5 kg ( 109 lbs. )
Feed Device: 10-round box magazine
Muzzle velocity: 800 m/s ( 2624 f.p.s. ) @ 15rpm (30max)
Penetration: 20mm at 300m - 60° (40mm using APCR ammo)

Above are two of the largest anti-tank rifles of their time. Japan also produced a 20mm cannon, the Type 97. Probably the largest weapon in this class, weighing in at a massive 59kg (130 lbs).

As you can see by the photos these were pushing the limits of what could be considered a portable infantry weapon.
Even though these guns had superior single shot performance compared to either the Boys or Browning, their sheer size and weight were a major handicap. Combined with the fact that tank armor was quickly reaching thickness impenetrable by even these behemoths, the days of an effective anti-tank rifle were over. However the Solothurn and Lahti continued to find service roles as long range light "sniper" artillery.
Here is a couple of interesting sites worth a vist: Jaeger Platoon      WinterWar