All snipers have the same gun ability if you have at least a +1 bonus with it:

Snipers have advantage instead of disadvantage on attack rolls at long range.

Barrett-50 : 130 Gold

1d10 Piercing, 300ft (450ft) Range

(1 Shots Until Reload)

RMB-93 : 180 Gold

1d12 Piercing, 400ft (650ft) Range

(1 Shots Until Reload)

M21 : 235 Gold

1d20 Piercing, 800ft (1000ft) Range

(1 Shots Until Reload)