45 Colt

The .45 Colt (often incorrectly referred to as the .45 “Long” Colt) was introduced in 1873 and was originally loaded with around 40 grains of black powder behind a 255-grain lead bullet, which produced over 900 fps from a 7 1⁄2-inch revolver. 

The original Colt Single Action revolvers were built to fire black powder and are constructed from soft iron. The pressure that these firearms can withstand are limited.  However, over the years, both design and metallurgy has improved so that basic guns can fire more powerful loads.

SAAMI maximum average pressure limit for the .45 Colt is 14,000 psi 

As a general rule, manufactures will load to SAAMI specifications for ammunition listed for the relevant caliber.  Some manufactures will have more powerful cartridges than the SAMMI specifications and will label the boxes as such (Buffalo Bore, Grizzly, Garrett, Underwood, Cor Bon).   These more powerful loads require a stronger firearm.  The different categories of firearms and the expected maximum pressure acceptable is listed below.  These data has been extracted from the Reloader Magazine and other sources.

Warning:  As with all firearm use, it is expected that you will use good judgement and do your own direct research to ensure that you are operating the firearms in a safe manner.  Because Sleeping Dog Ammo is unable to evaluate your firearm, your skill or any other conditions of firearms you, only use can ensure that you and your firearms is being employed in a safe manner.  You are solely responsibility for all risk.

  • Black Powder Only
    • Revolvers – Antique
      • First Gen Colt SAA
      • Colt Frontier
  • 14,000 psi (SAAMI maximum pressure)
    • Revolvers – Antique
      • Second & Third Gen Colt SAA 
      • New Frontier
    • Revolvers – Replica
      • S&W Model 3 “top break” clones
  • 20,000 psi (45 ACP equivalent)
    • Revolvers
      • SSA Replicas (new production) – These have heavier cylinders that are 0.020″ larger than the originals
        • Uberti
        • Pietta
        • Beretta
        • Ruger New Vaquero (Manufactured 2005 – present) Updated to be closer to the original Colt SAA, but that also means less steel. The original Vaquero (notice the lack of “new”) is stronger, see its 30,000 psi entry)
        • Ruger “mid-frame” Flattop Blackhawk. Note: This is not as strong as the typical Blackhawk, see its 30,000 psi entry)
        • Colt New Service — large frame, double action, 1898-1946
  • 23,000 psi (SAAMI max 45 ACP +P)
    • Original Revolvers
      • USFA SAA (United States Firearms Manufacturing Company)
      • Model 1950, 1955 (rare in .45 Colt)
      • S&W Model 25 25-5, 25-7, 25-9
      • S&W Model 625
    • Rifles – Replicas — Original rifles were not chambered in 45 Colt
      • Winchester 1873 by Winchester, Uberti, Pietta
      • Henry 1860 (Modern) by Henry Arms
      • Henry 1866 (Modern) by Henry Arms
  • 30,000 psi /32,000 CUP — Known as “Ruger Only”
    • Revolvers
      • Ruger Blackhawk (Note: there is a Ruger Blackhawk mid-frame Flatop – see its 20,000 entry)
      • Ruger Vaquero (Manufactured 1993-2005) Built on larger frame and stronger. (Note, the “New Vaquero” is not the same — see its 20,000 entry.)
      • Ruger Bisley
      • Freedom Arms Model 97
      • Thompson/Center Contender
      • Colt Anaconda (Few manufactured)
  • 40,000 psi
    • Rifles
      • Marlin 1894
      • Winchester 1894
      • Henry Big Boy
  • 50,000 psi
    • Revolvers
      • Custom five-shot cylinder conversions
      • Ruger Redhawk
    • Rifles – Replica — Original rifles were not chambered in 45 Colt
      • Winchester 1892 
  • 65,000 psi — These are specialty firearms that are built extremely strong
    • Revolvers
      • Freedom Arms 83 (aka Casull model)
      • Magnum Research BFR
      • Thompson/Center Encore











Handloader Issues 217, pp 37-42

Handloader Issues 246, pp 12-15