My favourate weapons are known as 'specialty rifles.' These weapons are designed around a single purpose, normally assassination. They tend to be specially designed, hence the name, around assault rifles but geared up to extremes. In the vast majority of cases, the bullet grain is deliberately reduced to keep the round below 950 feet per second, the breaking point of sound, while a internal suppressor takes care of the flash and reduces the sound of the shot at the gun itself. On top of this requirement they are also designed and developed to have the tightest grouping of any weapon known to date and, of course, are scoped. This is why specialty rifles are often mislabeled as sniper rifles, because they use a scope and have pin-point accuracy, but the round size and range are those of an assault rifle.
A good example, and my favorite in particular, is the Vintovka Snayperskaya Spetsialnaya series of rifles. This weapon was designed around the suppressed ammo, СП-5 or СП-6, which is a 9mmX39 round with excellent penetration even traveling at sub-sonic speeds. This rifle does not require hearing protection, at only 120 decibels*, and effective out to 300-400 meters. It boasts a MOA of around 1, which is an inch for every 100 yards, and that is sniper quality. They do not have the effective killing range as a full rifle, but given you rarely fire a rifle at a target more then 100-200 meters away the less range is not much of a loss in my eyes.
The Vintovka Snayperskaya Spetsialnaya Krupnokalibernaya is very nice, firing a 12.7mm STs-130 round for extra penetration and range without loosing the sub-sonic ability of the СП-5 and СП-6 rounds.
*sounds loud on paper, but you have to realize this is a sliding scale. A rifle at 130 decibels is twice as loud as one at 120 decibels. A .22LR fires at 140 decibels and a 30.06 rifle will fire at 160 or so decibels. Handguns are around 150 decibels, unsuppressed, so this rifle has about the same loudness as most suppressed handguns.