Porter Baldridge Page 8
Here is a brief history of the British loadings for the 303 cartridge.
| MK I | 20 Feb. 1889 | 71.5 grains black powder | 215 grain RNFMJ |
| MK II | 3 Nov. 1891 | 31 grains Cordite Mk I | 215 grain FPFMJ |
| MK II | 1 June 1893 | 31 grains Cordite Mk I | 215 grain RNFMJ |
| MK III | Exp. 1893 | 31 grains Cordite Mk I | 215 grain tubed HP |
| MK IV | Exp. 1893 | 31 grains Cordite Mk I | 215 grain HP |
| MK V | 17 Oct. 1899 | 31 grains Cordite Mk I | 215 grain HP (new core) |
| MK VI | 29 Jan. 1909 | 32 grains Cordite Mk I | 215 grain RNFMJ |
| MK VII | 3 Nov. 1910 | 37 grains Cordite MDT | 174 grain Spire FMJ |
| MK VII Z |
? |
Nitrocellulose | 174 grain FMJ M.G. use |
| MK VIII |
? |
Cordite MDT | 174 grain Spire Copper |
| MK VIII Z |
? |
Nitrocellulose | 174 grain Spire Copper |
The MKI loading did not last very long. The several rounds I have
loaded to duplicate this loading had tremendous recoil and muzzle
blast. These rounds were originally loaded with boxer primers, and
had a cupro-nickel jacket. The MKII was a cordite version of the MKI
with a flat point bullet to tell them apart from the MKI loading, and also
had boxer primers. Muzzle velocity on the MKI and MKII was 1850
f.p.s. The second MKII, IV, and V were all hollow points. The MKIII
had a piece of tubing forming the hollowpoint, the others were lead
cored. The MKVI went back to the original bullet, and had more
cordite. The MKVII went to a spire point FMJ bullet, and had 5 more
grains of cordite. This round also used the cupro-nickel jacket. Some
of this is still around, though of later loadings, and is not the best
ammo in the world. The MKVIIZ was the same round loaded with
nitrocellulose powder for machinegun use. It was far less erosive, and
cooler burning than the cordite rounds so that barrels would last
longer. The MKVIII loads were the first to use gliding metal jackets
(copper zinc alloy). This cut down on metal fouling of the bores.
Cordite MDT has less muzzle flash than the MKI cordite. The MKVIIIZ
load was again for machinegun use. Also note, all Canadian 303
© Porter Baldridge 1996 All rights reserved.