The disks are positioned upside down on the right side of the stock, because when the soldier who normally is a right-handed shooter, looks at the disk he will have the disk in the right position.

Upside down is a disk from a g m/38;
read the explanation below.

Here we look at a disk from a Ag m/42B;
read the explanation below.

The m/41 round had a much flatter trajectory than the older m/94. As most rifles were already manufactured with iron sights for the "m/94 bullet", the aiming correction in mills (how much lower you had to aim to hit the target) was inscribed on the brass disc. This is the information in the second sector. It was usually 0,5 mill.

The last sector gives information on the level of bore pitting. 1 means pitting in the groves. 2 means pitting in the groves and on the side of the lands. 3 means pitting in the whole bore (= unserviceable). A rifle would never receive a 3, it would instead be turned in to a work shop, where the old barrel would be exchanged for a new one.

Which means; Rifle number 20, at the bicycle-dispatch unit
(velocipedordonans), at the 3rd Army Division (armefördelning).
Only on carbine m/94.
 

Some later codes or abbreviations for regiments or other army-units,
that may appear together with a number:

Even later also:

Some weapons stored in the Armys Supply Services Armourys

    There was one exception from this kind of 'unit'-disk.
    The m/41 snipers rifle had a disk with the text;
                "G m/41 B"
   
    Which reads "Gevär m/41 B" ('Rifle model 41B').
 

The Swedish Navy often used;
 

The Navy used to be organized in four districts;

The Coast Artillery (that was a part of the Navy) sometimes used;

(HK was later changed to NK and KA4H was changed to KA5)

It seems like the Coast Artillery also used the KA1 - KA5 denotations.

The Navy also used numerous other markings, like:

Yes, there was a special sniper rifle version of the m/96 designated rifle m/41 ("Gevär m/41"). These rifles were selected species of "well shooting" m/96’s. Prior to the modifications their bores were checked and the rifles were fired for accuracy. The modifications consisted of drilling and tapping the receiver on the left side of the receiver and to mount a telescopic sight with mount. These sniper rifles are now obsolete, and were replaced in 1991 with the modern 7,62 mm sniper rifle PSG 90.

This rifle had a a two whole brass disk, which reads:

                "G m/41 B"
   
Translated - "Gevär m/41 B" ('Rifle model 41B').