Sniper Elite 4
86 Achievements
86-105h
Master-At-Arms
Fully master a rifle, secondary weapon and pistol
0.9%
How to unlock the Master-At-Arms achievement in Sniper Elite 4 - Definitive Guide
Tupacca
TrueAchievements
TrueAchievements
Only after you have completed all three of a weapon's upgrades will you be able to start making progress toward the fourth "Mastery" slot, which unlocks a special gold-themed skin for the weapon.
Once you have completed the mastery requirements for one weapon in each slot - rifle, secondary, and pistol - the achievement will unlock. You do not have to have all three equipped at the same time.
Just choose the loadout that works best for you, or that you've already made the most progress toward, and get to work!
Tips:
Play Survival Mode (on Cadet, in the Dockyard):
Ricochet Kills:
Penetrative Kills:
Double/Multi/Explosive Kills:
Shoulder-Aim Kills (rifles):
button. This will keep you in third-person view and let you aim over-the-shoulder just like secondary weapons and pistols. Thanks OddManRush for this tipShot Trap Kills:
Kills from a certain distance:
Organ-specific Kills:
Heart Rate Kills:
until your heart rate reaches the desired level. Then, quickly switch to the weapon you need and take out the target.Sound-Masked Kills:
Other Notes:
I think what I took away from that is that you may almost always get double kill XP for explosions including 2 enemies, but somehow those don't always count towards weapon mastery. All I can deduce from my attempts is that it might have to do with the proximity of enemies to each other when the explosion happens.
i am just wanting to see if anyone else has problems getting this achievement to unlock. i have now met the requirements twice. and it still shows locked.
fully mastered 2x rifle/smg/pistol....nothing
followed routine wait 72 hrs, delete profile etc and try again to get requirements, which i have.
i may have to get all other achievements first, delete save and start a new game and master the 3 weapons again
Combatting, DISCOKING, and, yodasqua
for more information on how to master the sniper rifle.Let's take the Welrod and Thompson as prime examples as these are your starter weapons. To see how you are doing head to the player loadout click on your desired weapon > press
> then 
for upgrades.For the Thompson, you need to unlock the following:
- Damage - 10 ricochet kills - Bullet rebounds - To gain easy kills aim your Thompson to the ground near the enemies feet, the bullets should bounce from the ground into the enemy
- Accuracy - 2km total kill distance
- Range - 50 Kills from above
- Mastery Skin (once the other 3 are unlocked) - 100 headshots
For a visual reference, see below:
For the Welrod, you need to unlock the following:
- Damage - 15 environment explosive kills
- Accuracy - 25 kills over 30m
- Range - 50 kills from above
- Mastery Skin (once the other 3 are unlocked) - 100 headshots
For a visual reference, see below:
bLaKgRaVy
This achievement is similar to “A Most Singular Expert” with the exception that you have to master all three weapon types, not just one.
To earn a mastery for a single weapon, you must complete three upgrades before you can perform the mastery upgrade. Each weapon has different upgrade requirements and all involve killing enemies in a variety of ways. To see what upgrades are for each weapon, highlight the weapon type in your loadout and press 
to view a list of all the weapons of that type (purchased or otherwise). Scroll through them, highlight the desired weapon and press 
(Skins/Upgrades). On the next screen, press 
to select Upgrades and it will show you what the upgrades are and your progress towards each one.
As you will see, most upgrades require you to grind out kills over and over again. You can use the save game feature and keep reloading or unlock them naturally through playing the game.
Once you’ve completed all four upgrades for any weapon, you will have mastered it (unlocking “A Most Singular Expert”). Repeat this for the two other weapon types and the achievement will unlock.