Fallout weapons facts Fallout 3 edition, Part III The sniper rifle is "An older model of the DKS-501" from earlier Fallout games. Their are many elements of several long range weapons here.
Sniper rifle retexture at Fallout 3 Nexus - Mods and community
ArtStation - Fallout DKS-501 Sniper Rifle
Assault Rifle Fallout 3 | Peatix
Fallout 3: Top 10 weapons (Scribe Slendy's Personal Log) - Album on Imgur