I'm reading "The Art of Warfare in the Age of Napoleon" by Gunther E. Rothberg.
In it he claims the following: "In most continental armies, therefore, the numerous Jäger units were simply light infantry and usually only partly equipped with rifles. In the British army there were two rifle-armed regiments, the 60th and the 95th, though the famous Light Brigade... in the Peninsula for the most part carried modified issue muskets."
I have looked at other internet sources and have been able to find no other information corroborating this. Is he simply incorrect here? What exactly is a "modified issue musket" in the first place?
This may simply be poor wording, as I believe the author is referring to the Light Brigade when he claims that they mostly carried muskets, which is far more understandable, given that the Light Brigade also contained regiments of regular light infantry such as the 43rd Monmouthshires, who would have carried muskets. I have also seen some reference to elements of the 60th Rifles carrying muskets at some point during the Napoleonic Wars, although this likely was for logistical reasons, and certainly not standard practice.
As for a modified issue musket, this seems to be a reference to the 1805 New Land Pattern Light Infantry Musket, a variant on the 1803 New Land Pattern that had been proposed for British service. Although interested, the Ordnance Department postponed its issue until c.1811 due to production issues, when it was issued widely to units going into the Peninsular War. The Light Infantry musket differed from standard weapons in a few aspects: it had a 39in barrel to make it lighter, as well as a scrolled grip, smaller lock and rudimentary sights, aimed at making the gun lighter and more useful for distance shooting.