.55", Boys Anti-Tank rifle. Mark 1, Mark 1*, Mark 2
(U.K. and Canada)
Picture shows 1x .50BMG round and 2x .55 Boys rounds.
All Boys ammunition was
originally supplied on 5 round stripper clips, 2 clips per small fabric pouch
(see image below). Drill rounds were available as well as lightweight aluminum
cored training rounds. The dimensions of the .55 Boys case are so similar to that
of the .50BMG case that it is highly likely that the Boys ammunition was evolved
from the 50BMG case, the base diameter, length and diameter of the portion of
the case on the upper side of the belt is exactly the same. Re-sizing a .50 case
in .55 dies produces a case that will chamber easily in the .55 rifle but the
angle of the slope on the case neck is slightly different and so would need
fire-forming, and naturally the case needs trimming. Australian owners of .55
Boys rifles have successfully modified 50BMG cases after passing them through a
.55 die, trimming the case to 3.90" and using epoxy to bond a ring to the case to
from a belt. The advantage of using these cases are that they are both plentiful
and often Boxer primed.
Boys belted case on the right.
.55 Boys Case length (unfired)*
3.90” – 3.904”
Bullet, OD 0.562” [max 0.564”]
Bullet, length (AP) 1.95” -
Belt, OD 0.850”
Section immediate above belt, OD*
Base, OD * 0.80” [0.798”]
Neck, OD, measured 1/8” before case mouth (unfired)
Neck, OD, measured 1/8” before case mouth (fired)
0.614” – 0.618”
Neck, ID, measured at case mouth (resized)
Neck, ID, measured at case mouth (fired)
0.569” – 0.574”
*same as .50BMG)
Not all Boys
ammunition was armor piercing, light weight training rounds were
manufactured, as well as tracer rounds.
is tracer (head stamp to the left), right is 15mm BESA for comparison.
drawing of .55 case, click for larger image.
Primer, Percussion, Kynoch No. 153A
Diameter 0.317”, Depth 0.154”
Primer, Percussion, CCI No. 35 for 50BMG (for
comparison) Diameter 0.317”, Depth 0.213”
Above: A selection of Canadian made ammunition pouches for
the Boys rifle.
Below: Wooden ammunition crate holding 160 rounds.