From "The Evolution of Arms Law (1980-2003)" by Brent Knorr:
RMSS (Rolemaster Standard System) was a major rewrite of the Rolemaster system, which took place in 1995. Surprisingly, Arms Law didn’t change much other than in format. This is mainly because the rules for Combat are moved into different book, the Rolemaster Standard Rules book. All the rules for combat that had been in the Second Edition Arms Law are moved to the back of the RMSS Arms Law as “Appendices, How to Use Arms Law without Rolemaster”. The actual content of this section was virtually unchanged from Second Edition.
The book itself is square bound, 144 pages, three hole punched, with perforated pages, which theoretically would allow for easy removal of the charts. In practice, the perforations are often too close to the hole punches and you were better off hacking off the spine if you wanted to remove the pages. The pages themselves are on ordinary paper, so if you remove them, you have to either laminate them or put them into page protectors if you want them to last.
Some of the changes include the removal of the Armored Fist Attack Table and the addition of the Brawling Attack Table. The Brawling Attack Table is in the format of the Claw Law Tables, landscape with Maximum Results for various sizes whereas the Armored Fist Attack Table had been in the format of the Arms Law Tables.
Two new Critical Strike Tables are added, the Brawling Critical Strike Table and the Subdual Critical Strike Table. A Non-Weapon Fumble Table is also added.
Breakage numbers for weapons are added to the attack tables.
The format of the tables is very similar to those in Second Edition, the Critical tables are slightly reformatted to have more color text and symbols added to indicate rounds of bleeding, stun, must parry and no parry. Although the color text did change somewhat, the actual combat effects remained the same. Most of the additional page count was used up by printing the Critical Tables appropriate to the Attack Tables on the back of the each Attack Table, half size if there are two appropriate Critical Tables.
Somehow, in this printing, the Dagger attack table lost the line for a result of 60.
All the Tables did get renumbered in this printing so they are no longer the same as previous editions of Arms Law.