Link: Copy link
Greg Renault:13434 wrote: 2. The next lower level of respect performed under arms is the salute. When the soldier is at the right shoulder light infantry/advanced arms carry, the left hand is brought over to the firearm on the right. This is done whenever a hand salute to the cap would otherwise be performed by a soldier not under arms. As this motion must be done from the position of shoulder arms, rifle and light infantry ORs that happen to be at Support Arms need to come to Shoulder Arms before they can salute. So they Carry Arms to come to the shoulder, then perform the salute. Conveniently the last motion of Carry Arms ("settle the Rifle firm against the shoulder") only needs to be held in order to perform a salute.
The equivalent salute for soldiers under arms from the battalion companies, whose carry is on the left, seems to be Recover Arms. As Eddie points out, this form of salute is also prescribed for rifles in the 1801 Green Book, but is supplanted by the left hand salute in the 1813 SOs of the 85th. I think this reflects a general, gradual trend in our period towards simplification.