.303 BRITISH --This cartridge is ideally suited to cast bullet use. Excellent accuracy equal or better than Jacketed Bullet performance can be obtained from standard barrels and the 2 groove war production barrels.
It is not uncommon to find significant wear in some of the old Lee Enfield SMLE rifle barrels and this should be taken into consideration when choosing the cast bullet design and diameter you will use. We recommend sizing to .313” minimum with .314” often a better choice.
Bore sizes are generally consistent at .303” while groove diameters we have measured range from .312” up to .314” in standard barrels. The 2 groove barrels we have measured again are consistent at .303” bore size but even new barrels can be as large as .318” in the grooves. This is one instance where an undersize bullet can still perform as the wide lands in 2 groove barrels displace a large amount of the driving bands and this displaced alloy tends to fill the oversize grooves.
Our bore riding nose type designs feature nominal .303” nose diameters. Some of our later designs have slightly larger nose diameters from .304" to .305". Illustrations available.
.310 MARTINI CADET
This popular single shot rifle has a bore size of .310” and a groove diameter of .316” to .318”. Similar in size to the Winchester 32-20 , the .310 Cadet was originally loaded with a Full Metal Jacket projectile as required for Military use and a swaged lead projectile for target work. The cartridge/rifle combination was found to be very accurate and was popular in the early 1900’s as a “Miniature Target Rifle”. Large numbers were shipped to Australia as training rifles for Cadets and in WW2 they were provided for use by Home Guard defences in the event of an invasion by Japanese Forces.
Experience has shown that heeled projectiles with diameters from .318” to .323” give best results as the gently tapered throat on these barrels actually measures around .325” in front of the case mouth. Chamber castings show there is no step in the chamber . Barrels we have examined show a smooth polished leade ideal for cast bullets. Case thickness varies between original and modern manufactured brass and most modern cases will not chamber with projectiles having a heel much larger than bore size (.310”) and in some brass the heel needs to be even smaller.
C.B.E. offer the widest variety of projectile designs available anywhere for this caliber. In the photo below on the top left is a .310 case loaded with our most popular design # 320-120. Beside the cartridge on the right is a fired projectile recovered from the mound . Note that the heeled section ( just visible between the lube groove and the rear) has expanded and is fully engraved by the rifling. The heel was .310” before firing and expanded to fill the .318” groove diameter. Smaller diameter heels will also upset provided the alloy is not too hard. The more the heel has to upset the more effect it can have on accuracy so bigger is better in this situation. Illustrations availableAvailable
577-450 Martini Henry
This venerable old cartridge although .45 Caliber , requires oversize bullets for best results. We offer several designs in both lubricated and paper patch bullets to suit. Illustrations available.