55 Boys Gerlich or Janacek

I am trying to find out the official (if there ever was) designations for the experimental Gerlich type bullets in the .55 Boys cases - the standard .55 and the approximately .60 cases.

ECRA calls this one the .55/.40 Janacek/Boys. In all my reading about the Boys cartridges I never came across a Janacek reference. This is a replica cartridge & I want to headstamp it with the appropriate name or designation.


ECRA calls this one the .60/.45 British XPL Gerlich on .55 Boys case.

I know a lot of documents are out there, I am hoping someone has a drawing with the designation on it.

Didn’t the British use the cover name Littlejohn (English translation of the family name) for this barrel system?

I am not sure, hence the question. As far as I know the Janacek design had a folded forward flange:

The Gerlich design had the two (or more) flanges designed to fold back as they were squeezed down.

As far as I know the Janacek or Littlejohn designation was not used for small arms ammo but I could be wrong.

Will, what caliber has the projectile you are showing? 37mm or 40mm?

Peter Labbett’s classic book “British Small Arms Ammunition 1864-1938” has an 8-page section on “Cone Chamber Experimental Ammunition 1929-1938”. This shows that both Gerlich type (tapered bore) and Janacek type (tapered muzzle attachment) small arms and ammunition were tried in many variations, plus another by Mr E Cantin, which had the bore partly tapered. Most of the work was with the Gerlich system using .5 inch Vickers, .50 Browning and 20mm Madsen cases. The Janacek work came later, and included .55 Boys.

The difference in the projectile design is that Gerlich bullets have flanges or skirts which are squeezed down, whereas Janacek projectiles have a collapsible outer body which folds down on the core.

Hi Will,

The other reference is the Labbett & Brown Technical Ammunition Guide 2/8 - British Anti-Tank Rifle Ammunition 1917-1945. Page 5 shows the .55/40 Janecek.

As for the ‘Gerlich’ inspired solid brass , I don’t have any drawings, but Janecek did design projectiles that look far more like Gerlich types. These projectile types are described by Labbett & Brown and here is a drawing.


Thanks guys, that has been a lot of help.

EOD, this is just a picture I found, it is labelled 40/30mm.

Will, thanks. So it is a 40mm/2pdr.