Hammer Strut Support(TM)(HSS) (patented)  
For 22LR Ruger Mark III & II Pistols and some Ruger MK I, Ruger Standard, and AMT Lightning Pistols

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HSS is fully compatible and a confirmed fit into Ruger MK III and MK II series pistols.
  • The MK II was manufactured from 1982-2005, followed by the MK III being manufactured through Dec 8, 2016.

HSS may or may not be compatible with the earlier Ruger Standard or MK I pistols. 
These were manufactured from 1949-1982.  In the some years, there were variations or manufacturing inconsistencies in the location of the "sear spring retaining pin", commonly referred to as the "cross-pin" on this website.  This seemed to happen mostly in the 1970s.
  • A minimum clearance space under the cross-pin of 0.038 inches is required to install the HSS.
  • Many people with the Ruger Standard and Mk1 pistols have installed the HSS with no problems at all, especially with the earlier models. 
  • 1968 models and older models do seem to work.
    • sn: 474XXX, 1968 does work.S

  • So far, this insufficient space problem has been found in the following Ruger Standard and MK I years and versions:
    • Isolated problems:
      • 1951 MK 1 with Bull Barrel, sn 32xxx (this was a singular case);
    • 1962: SN 218xxx (this was a singular case)
    • 1969 unknown compatibility: sn 10-00001 to 10-38889

    • Confirmed problems:
      • 1970 & 1971 all pistols; sn 10-38890 +
      • 1972 & 1973 all pistols; sn 11-xxxxx
      • 1974 all pistols; sn 12-22449 to 12-81987
      • 1975 unknown compatibility: sn 12-81988 + 
      • To see what year your pistol is, go to the Ruger website:  ruger.com/service/productHistory.html
      • The HSS has fit  AMT Lightning pistols (unauthorized clones of the Ruger MK II), but we do not know if it will fit all of them. 
      • We have a money back guarantee on our HSS.  If you would like to try the HSS on one of these earlier pistols, we will gladly refund your purchase price if it does not fit.  Just let us know the details about what pistol and what year it did not fit.

      HSS is not compatible with 22/45 versions, or the new Mk IV models.
      The 22/45 versions have an entirely different handle, which is modeled after the popular model 1911, 45 caliber, pistol.   The Ruger MK III 22/45 dos not have a cross-pin and uses a different kind of sear spring, so the HSS is not compatible with this model.
      We plan on developing the Hammer Strut Support for the 22/45 eventually.  There are multiple versions of the 22/45, some with and some without removable grip panels and the MK III 22/45 has a completely different sear spring and retention method.  Please check back again later, as we do hope to develop the HSS for applicable MK II models with removable grips.   This development would perhaps be late 2018.

      The MK IV models began to be sold in Dec, 2016.  These have a "tip-off" barrel design, wherein the barrel can be rotated off of the frame, after depressing a release button.