WW1 cartridge quiz

Photo shows two British cartridges, the one on the left is headstamped 18 (1918) and the Mark 7 on the right is dated 16. Anyone know anything about this cartridge ?Attachment 58236Attachment 58235

The head stamp indicates Royal Laboratories Woolwich.

http://ator1149.home.xs4all.nl/wfm/w...tml#headstamps

Thank you for the chart showing the headstamp codes, but I already knew about the Royal Laboratories Woolwich headstamp code. Now perhaps you could identify the cartridge in question ?

It's an experimental .303 semi-rimmed Lewis MG cartridge. Worth about $5.00 on the ammo collector market.

Thanks for the answer to my quiz (I already knew the answer), now what I would like to know about the 303 Lewis cartridge is the bullet weight and velocity

Can't answer those off-hand, will consult the library tonight.

This is about what I can find, nothing on the bullet weight though. .303 inch Rimless - British Military Small Arms Ammo

Don't know if this is the exact same cartridge... .303” Enfield Rimless Experimental Cartridge Tested between 1920 and 1927. Five thousand rounds were produced, loaded with 48.7 grains of nitrocellulose power and either a 174-grain or 200-grain projectile. Case length was 2.21” and bullet diameter was a small .309”.

"The bullet is a normal Ball Mark VII"
That would make it about 174 grains, right?

The 303 Enfield rimless is a different cartridge from the 303 Lewis machine gun cartridge and to date, all the examples of the 303 Lewis have the 1918 date on the headstamp