schmanman; et al. (March–April 2007). "(NEW) S.W.A.T v.3". SpudFiles. Archived from the original on 2 February 2013. Retrieved 16 August 2011. Cannon with a calculated range exceeding 1 mile.
BigBang (October 2006). "Crusader". SpudFiles. Archived from the original on 20 February 2009. Retrieved 2009-06-01.
schmanman; et al. (March–April 2007). "(NEW) S.W.A.T v.3". SpudFiles. Archived from the original on 2 February 2013. Retrieved 16 August 2011. Cannon with a calculated range exceeding 1 mile.
Killjoy (25 April 2007). "FEAR". SpudFiles. Archived from the original on 27 February 2015. Retrieved 2009-06-01.
Novacastrian (November 2007). "The Brass Bruiser". SpudFiles. Retrieved 2009-06-01.
Technician1002 (4 April 2009). "Quick Dump Valve". SpudFiles. Retrieved 16 August 2011.{{cite web}}: CS1 maint: numeric names: authors list (link)
jackssmirkingrevenge (8 September 2007). "high velocity burst disc 6mm pneumatic". SpudFiles. Retrieved 16 August 2011. Attained approximately Mach 1 (340 m/s; 1120 ft/s) with 400 psi (2.8 MPa) and a fast valve.
"New stuff". The Spudgun Technology Center. 14 January 2010 [6 July 2002]. Retrieved 16 August 2011. "Theory/physics behind the spudgun". The Spudgun Technology Center. 29 August 2008 [25 June 2002]. Retrieved 16 August 2011. Used helium to attain supersonic velocities.