.45-90 Winchester

In an effort to resolve the difficulty caused by the single shot Martinis the Royal Flying Corps purchased a number of Winchester Model 1886 rifles in .45-90 calibre. These relatively light handy weapons had a magazine capacity of ten rounds and were capable of rapid operation even when encumbered by heavy clothing.

.45-90 Winchester Model 1886

Commercial full length .45-90 round

The standard commercial .45-90 round utilized a 450 grain bullet with a charge of 90 grains of black powder, to give a velocity of around 2000 feet per second. The case was 61mm long and the overall round length was about 71mm.

In British service the .45-90 rounds were loaded with two types of projectile, an incendiary based on the Royal Laboratory design and a tracer based on a scaled up .303 inch S.P.G. design.

Left: RL Incendiary with Winchester manufactured case

Right: S.P.G. Tracer in Eley Bros. manufactured case

Interestingly, the British loaded incendiary and tracer rounds utilized a shortened cartridge case of between 49 and 51mm in length irrespective of case manufacturer, both Winchester and Eley cases being used, with the bullets seated further out of the case so that the overall length of the round was similar to the original. One reason for this may have been concerned with the shape of the special purpose projectiles. Due to the tubular magazine, the original commercial loads feature a rather squat blunt lead bullet that had a low ballistic coefficient; the British special purpose loads, whilst still blunt nosed for the tubular magazine, had a more slender ogive, presumably to improve the ballistic performance.

A consequence of this was that if the bullets had been seated in their normal position in the standard length cartridge case the overall round length would have been too long, since owing to the design of the Model 1886 the overall length of the round is fixed to enable the magazine and cartridge feed mechanism to function correctly. By shortening the case, the bullets could be seated in their relatively normal position whilst maintaining the overall length of the cartridge.

In addition, these rounds used smokeless propellant, unlike the originals, and therefore needed less space in the cartridge case. The shorter case combined with the longer special purpose bullets may have been required to ensure proper burning of the propellant charge.

A consequence of this was that if the bullets had been seated in their normal position in the standard length cartridge case the overall round length would have been too long, since owing to the design of the Model 1886 the overall length of the round is fixed to enable the magazine and cartridge feed mechanism to function correctly. By shortening the case, the bullets could be seated in their relatively normal position whilst maintaining the overall length of the cartridge.

In addition, these rounds used smokeless propellant, unlike the originals, and therefore needed less space in the cartridge case. The shorter case combined with the longer special purpose bullets may have been required to ensure proper burning of the propellant charge.

Royal Laboratory Incendiary

The incendiary bullet developed for the .45-90 was based on the Royal Laboratory Flaming bullet design originally used in the .577/450 Martini case. It consisted of a hollow brass bullet, filled with the incendiary composition and closed with a screwed steel plug. It differed from the Martini round in being flat nosed, a requirement of the tubular magazine of the Winchester.

The shortened case was made by Winchester with a Boxer primer, although British made cases were also probably used.

Bullet length was 32mm and the filled weight was 237.5 grains.

Left: .45-90 RL Incendiary bullet "Winchester High Velocity" headstamp

SPG Tracer

There were two sub types of SPG tracer, one boat-tailed and the other not. Both consisted of a hollow cupro-nickel bullet filled with the tracer composition and a small amount of igniter composition pressed at the base. The base of the bullet was left open.

The shortened case in the example shown was made by Eley Brothers with a Berdan primer but it was likelt that American cases were also used.

Bullet length was 32mm and the filled weight was 260.5 grains.

Commercial .45-90 round