Enlarged chamber marking?

[TonyE]

No, the problems encountered with the L.E. Mark I* rifles was different. These rifles were sighted for the older heavy 215 grain Mark VI bullet which was round nosed, and the magazine lips were set up to feed this ammunition. Since the regular army werere using the later (Post 1911) Mark VII ammunition the Territorials were issued with this in the field. This had the lighter 174 grain pointed Mark VII bullet and this did not feed well in magzines set up for Mark VI. Consequently their rifles frequently jammed due to mis-feeds causing the round to tip up as it was being fed. Picture shows the two rounds below.

Returning to the original question of the problems with the Ross, I have to disagree with Smellie about the cause and the "E" chambers. Whilst it is certainly true that there were problems with some British ammo (more on that below) the real cause was the way the Ross was made.

When the problems first occurred it was found by Lt.Col. Harkom, the technical advisor to the Canadian Standing Small Arms Committee, that Ross chambers were undersized. The British specification for teh mouth of the chamber was .462", yet the Canadian specification was .460". This was compounded by two factors. Ross was chambering his rifles to .458" and furthermore the rifles were gauged before assembly and not before. Therefore when the barrels were breeched up any over zealous tightening resulted in the chambers being squeezed even tighter. Since Bitish ammo was being made to a specification of .462" it was trying to fit in a .458" or tighter chamber.

Now for the ammo problems. It was also found that some British ammo, particularly that from Birmingham Metals and Munitions Co., made during the great production expansion of 1914/15 had cases that were too soft. They would be forced into the tight chamber, expand when fired and because of the wrong hardness gradient become completely stuck.

It transpired that the reason the Ross rifles had worked in Canada was that Dominion Arsenal (the Canadian ammunition facility) was only accepting and passing minimum dimension cartridges. Quite how the situation had been allowed to arise whereby Canada was manufacturing rifles and ammunition to different tolerances to the imperial norm is not known.

Harkom instructed that chambers should immediately be manufactured to .462" and from 9th July 1915 these rifles were marked with an "N" on the chamber for "Normal". As the problem persisted the chamber dimension was increased to .464" on 15th August 1915 and it is these rifles that are marked with an "E" for "Enlarged".

For rifles already in the field in the UK Harkom had all the chambers of the 2nd Canadian Division reamed to .464" before they sailed to France. These are marked "LC" for "Large Chamber".

Thus it can be seen that the Ross problems were principally of Ross's own making and cannot be put down simply to badly made British ammunition.

Subsequent Ross problems with too small bolt stops and soft or brittle lugs are another story...and that was certainly a Ross problem!

Regards
TonyE