Antique 310 Cadet

Loading for the 310 Cadet Brings Back a By-gone Era

If you are looking to begin loading for antique cartridges, the 310 Cadet (or 310 Martini) is a great place to start. This fun cartridge was used to train cadets in Australia and this explains the name. Using the same action as the 577/450 Martini-Henry but shrunk down to suit youth, the 310 Martini is a lightweight, fun rifle to shoot. The report is mild and the cost to feed it is moderate. In a world where .22 Long Rifle ammo sells for $8/box, the 310 Cadet is quite modest.

It is similar to the 300 Rook but there are a number of differences regarding bullet design, weight and energy.

The photo shows a comparision of the 22 Long Rifle; 22 Magnum; 300 Rook; Factory 310 Cadet; Factory 310 Cadet; Fired 310 case; 125 gr 310 bullet next to 40 gr .22 Magnum bullet.

The 300 Rook uses a 80 gr inside lubricated bullet versus the nominal 125 gr outside lubricated 310 bullet. While the case dimensions are similar, the 300 Rook bullet is 0.300″ compared to the heel type 310 bullet that measures 0.324″. The 310 Cadet is no slouch and it packs a real punch as the table below shows.

Some references list a velocity of 1500 fps but no factory ammo, that I have chronographed, has come close to that. Also this round has not been factory loaded for over 30 years. However, it is simple to get to 1300 fps and that is ample energy for anything that you plan on shooting. The authority of the round hitting steel plates is impressive.

The only difference in loading, compared to most rounds, is the it uses a heel type bullet. Just as for the .22 rimfire, the base of the 310 bullet is a smaller diameter than the shank and it slips inside the case. Like the .22 rimfire, the 310 bullet lube is all exterior to the case. While it does have a lube groove it is easier, after it is loaded, to lubricate it with liquid Alox (the Lee brand is readily available and works great) and let it dry. Even after it is dry, some care is needed to prevent the bullets from picking up dirt. The barrel fouling potential with this round is low and a fully coated bullet virtually eliminates leading even at 1300 fps.

Picking up a svelte, Martini-Cadet rifle brings back memories of simpler times of kids taking a rifle on a Spring day and wandering through fields plinking. A far cry from the paranoid gun fears that the media constantly echoes today. Loading a 310 Cadet will not change the media narrative but for a few hours, we can enjoy the fun of shooting this unique cartridge.