B, N and G and some other cases were found to be defective in specifications in 1914 and 1915, causing dangerous jams in Ross Rifles (Canadian forces) on the Western Front, and lead to the withdrawal of the Ross Rifle from use ( amongst other problems) (“The Ross Rifle Story”).
The Problems were several in case manufacture…oversized head diameter, over-long head to shoulder length (improper sizing after Crdite filling) and over-diameter neck.
Whilst in the SMLE, these problems were overcome by enlargening the Chamber specifications, this did not solve the problems in the Ross.
The worst Cartridge defect was the Head to shoulder Length problem, which prevented closure of the bolt, as well as jamming the cartridge in place, and not allowing the bolt to easily open.
Dirt and mud also compounded this problem…The Ross Rifles were toleranced to use Pre-War Canadian specification.303 Ammo, Not the slipshod nritish production of the 1914-1916 period, in Factories which had been set up only in late 1914 ( N especially). The Lack of trained staff and so on led to deficiencies in QA, leading to Over-sized ammo reaching the Front.
It was well known for Canadians to “Triage” ammunition before an advance or action, and eliminate all the B, M, N, G and sometimes J headstamped ammo, leaving it for Machine guns. The soldiers themselves, discarded their Ross Rifles in the field, and picked up British-Made SMLEs to use, as being “Life saving” despite Routine Orders NOT to do so; when the Canadian Forces finally abandoned the Ross in 1916, and issued SMLEs, it was found that over 3,000 SMLEs were already in the hands of Canadian Troops ( “Battlefield Pick-ups”).
The massive increase in both quantities produced, and new Plants established, led to a shortage of trained Workers to ensure correct production. And the Soldiers in the field were affected ( sometimes fatally).