I’ve had two .240 Belted Rimless NE cartridges for a long time. Just noticed that they appear to have different shoulder angles. Both are by Kynoch and appear to be factory loaded. Both have the same shoulder location when measured from the base. Anybody know anything about this? Or do I just try to measure the angle and keep the “correct” one and discard the other?
You may be stuck with both of them. The chambers for belted cartridges are notoriously oversized, so exact placement of the shoulder might not be that critical. On firing, the case will expand into the “swamp chamber” and the shoulder will be noticeably pushed forward. The old trick for both improved case life and accuracy is to neck size fire cases. Pushing back the shoulder at every reloading will lead to eventual head separation.
The advertised purpose of the belted case was that the combination of the belt and a loose tolerance chamber would provide reliable functioning under adverse conditions. Reloading is left completely out of the equation. The size and shape of the shoulder of a belted cartridge must fall between a minimum and maximum material condition, which is probably a generous tolerance by design. Manufactures may have keyed in on this situation and built perfectly functional cartridges that were perhaps slightly modified to suit process requirements. I think this is what you have, given that both cases are in original unfired condition… or maybe not?
As above, the shoulder is not critical. They were designed to be a loose fit and were never intended to be reloaded. Reloading was virtually unheard of in Britain at that time and if you could afford a H&H rifle you would not be likely to be considering it as an option.
What one must remember, besides the fact that such British cartridges were “use once, throw away” tupes (by Practice), the Majority were Cordite or Axite Loaded, both types of NC which required the cases to be formed AFTER filling ( as with the .303 Cordite). That feature, along with the “ample” Chambers of Belted cases, required that the shoulder be in a Position which “cleared” the Chamber shoulder without binding. so the Shoulder Position could vary due to tool setting in the Forming Process from Lot to Lot.
Such a difference was crucial in WW I, to the Failure of the Ross Rifle in the 1915 Trenches ( over-Long shoulders on .303 from “New” factories where Toolsetters were inexperienced). In sporting ammunition (ie, in peace time), gauging was better, as was the tool setting, so that even with a small Variation in shoulder Position, the cartridges would Load into Most, if not all, rifles chambered for the Calibre.
Even Taylor decries Handloading/reloading in Africa, as “dangerous” if the Person was not fully au fait with the Process…that is why he always ordered his cartridges direct from Kynoch, in tin-sealed 100 round canisters, for use under any conditionsd, knowing thjat they were always reliable and not liable to deteriorate. The fired cases went to his Bearers, who prized them as trophies for themselves and their wives (Plural).