considered that this system is entirely suitable for use in the 15 mm. gun as the operations of extraction and cocking will have to be done by hand For each shot.. If, however, success is achieved in the Boys rifle, the Board will arrange for some 15 mm. conveyor rounds to be manufactured and issued to A.F.V. School for trial. It will have been seen that the practicality of an equivalent conveyor system for the 15mm BESA gun was also under consideration, and its future would rest on the success, or otherwise, of the system for the Boys ATR. The comprehensive Trials' Reports memorandi can be viewed separately from this link. These letters date between April and August 1940. A North American equivalent to the Parker-Hale conveyor was manufactured in Canada by the Cooey Machine & Arms Company. In his reference book "The Lee-Enfield Story", Ian Skennerton refers to that company producing "77,000 aiming tube conveyors which enabled .22-in. R.F. ammunition to be used in the Boys anti-tank rifle for training". Actually, the Cooey conveyor was not strictly speaking an aiming tube system, which might also have afforded magazine-fed firing practice, and such a sleeve would have been a full-length rifle barrel in its own right, with an outside diameter of a nominal half-inch, that remained in place in the parent barrel during loading.. However, the difference between the Boys' adaptation and the "303" cum 22" conveyor was that the Boys' model had a rifled bore instead of a smoothbore one, and the .303 conveyor for the SMLE fed the .22 bullet into a .22 barrel, although the .303 P-H conveyor for the Vickers machine gun did fire the .22 bullet straight down the .303 barrel - at very short range though. So, what's in a name?. To recap', the Cooey conveyor - shown right - closely resembled the Parker-Hale design, which also fired the .22 round through the .55 barrel, the bore- length of the conveyor being sufficiently great to approximate the accuracy of a short-barrelled .22RF pistol, perfectly adequate for miniature range use. Although Parker's much earlier version of their ".303 cum .22" conveyor, when used for miniature range practice with the Vickers or Lewis Machine Guns, utilised no tube or sleeve, merely firing the .22RF round through the .303CF barrel's bore; not the most accurate system, even at the twelve yards range at which it was normally used, but most useful for the training and assessment of budding Machine Gun operators. We illustrate both a drawing of the Cooey conveyor, and a mocked-up sectional representation showing the .22RF cartridge at the approximately correct scale. It will be seen that, like the Parker-Hale version, the Canadian version used a separate firing-plug with double firing-pins to distribute the striker pressure evenly across the rim of the .22RF cartridge. In the past, similar rimfire adaptors have been bored eccentrically to permit striking of the rim by a centre-fire firing pin, but this necessitates constant radial orientation of the adaptor in the parent chamber. Image - left - by courtesy of E. Molyneux Image - right - by courtesy of A.O. Edwards Another little known training arrangement for Canadian use of the Boys ATR was the adaptation of two obsolete .303 service rifles to replicate the ATR. The first rifle so adapted was the Canadian's own design of straight-pull Ross rifle the bolt action of which bears a realistically close relation to that of the Boys ATR - each being of straight-pull action with a helically operated rotating bolt-head utilising a forward-locking interrupted thread. The second rifle so adapted was the Magazine Lee-Enfield - otherwise long out of service on either side of the Atlantic Ocean. Again, these training rifles would have permitted comparatively realistic practice on standard military ranges either at the very few hundred yards at which the real ATR would be employed, or on the short 30 yard practice ranges. The use of these converted obsolete rifles would also have prevented the retention of genuine Anti-Tank rifles for training when they were urgently needed elsewhere. This is a factor that, early in the War, may have played a part in the fairly restricted employment of both the .22 adapters and the proposed .55/.303" CF practice round discussed further down this page. Below is a facsimile of the drawing for the Ross rifle's adaptation, with apologies for the poor and distorted reproduction reconstructed from a badly torn and crumpled document, and on which we eventually hope to be able to improve..