.17-357 RG

Cartridge Data Published On: December 20, 2014 at 11:36 pm by Bullet-Blog and last updated on February 12, 2015 at 11:23 am


.17 Real Guns


The .17-357 RG (AKA: .17 Real Guns) is a Center Fire cartridge with a Bullet Diameter of 0.172 in” (4.37mm) that is primarily used in Pistols and Rifles. The .17-357 RG originated in The United States in (UNKNOWN DATE). The .17-357 RG also has a case length of 0.865 in” (21.97mm) and an overall length of 1.26 in” (32mm).

Additional Cartridge Designations: Wildcat Cartridge


The 17-357 RG is the product of necking down a .357 SIG Cartridge to accept a .172″ (4.37mm) Caliber Projectile. The total neck reduction is done over 8 steps, and reduced the case neck by .158″ (4.01mm). The 17-357 RG uses a 20-25 grain bullet, and load depending, is capable of sending a projectile down range at over 3300fps.

The .17-357 RG was created by Realguns.com editor Joseph Alessandro and was tested in the Thompson Contender Single-Shot pistol. Test results and load data can be found at the Real Guns website, and all data listed on the .17-357 RG load data page on realguns.com is marked as being MAX load data for the Thompson Contender pistol and “may easily be excessive in other..” pistols.

Associated Firearms

Thompson Contender

Cartridge Details

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  • Neck Diameter:
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  • Primer:
  • The United States
  • Rimless, Bottleneck
  • Pistols
  • 0.172 in” (4.37mm)
  • 0.203 in” (5.16mm)
  • 0.424 in” (10.77mm)
  • 0.424 in” (10.77mm)
  • 0.424 in” (10.77mm)
  • 0.06 in” (1.4mm)
  • 0.865 in” (21.97mm)
  • 1.26 in” (32mm)
  • 12.2 gr H20 (0.79 cm3)
  • Center Fire (Small Pistol)

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