"mauser" is the name of the design, and that design is from the late 1800's. most rifles since then are described to have a "mauser action" which was so named to differentiate it from rifle designs in use back then.
https://en.wikipedia.org/wiki/Mauser
as i stated to someone on facebook - the rifle used is essentially a deer rifle, a 200 yard shot is not that difficult. somewhere i have a target that i shot at 100 yards and grouped 3 shots together that can be covered by a nickle. the bullets impacted right where i wanted - 1.5 inches higher than i was aiming. setting the sights to do this will put the bullets right on the aim point at 200 yards or maybe a quarter inch lower than the aim point. this was taught to me by my dad back in the 70's so this is not new wisdom.
my opinion - one does not need to be a trained sniper to hit the target at 200 yards. if anything, a weekend on the range, 1-2 hours for 2 days, could make one competent enough to do this consistently. the fact that the bullet impact the side of his neck also leads me to believe the shooter was not that well trained.