Based on the PTRS-41 Anti-material rifle, a gun used by the Soviets during WWII. I wanted the Sniper to have a big-calibre gun, but Svdl has already tackled the Boy's Anti-Tank rifle better than I could ever do, and the Barrat has been done to death, plus, it doesn't really fit with TF2.
The PRTS-41 is something that would exist in abundance during TF2's timeline, however, so it makes sense Mann-Co would pick a few old models up, dust them off, give them a spit-shine and ship them out as new weapons.
Mostly glad that I was finally able to model, unwrap, texture, rig and compile this bastard by my lonesome. Granted, it was under Passerby's guiding hand, but I still did the work myself and I couldn't be happier with the results.