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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Hammer Strut Support(TM) (HSS) (PATENTED):  Installation-Read First!:

1.      Ensure pistol is not loaded.  (Tip: For MK III pistols, reinstall empty magazine and leave in throughout HSS installation.)

2.      See diagram at right:

3.      Remove Mainspring Housing Assembly & hand grip panels.

4.      Secure pistol with barrel away from you, with handle down.

5.      CAUTION: Using toothpick, paper clip, pin, punch, or  tweezers, slowly slide pistol Lower Cross-Pin (Sear Spring Stop Pin) which is near loose bottom end of pistol Hammer Strut to left as far as possible without releasing the spring under the left side of Lower Cross-Pin. (as shown in picture)

Note 1:
Some customers with very old pistols report having to use a pin punch and small hammer or wood mallet to nudge cross-pin free to begin.
Note 2:
Recovery procedure if you accidently retract the Lower Cross-Pin too much, releasing the spring.  (That spring is held, wrapped around the sear spring post, and cannot become disoriented or dislodged.)
a.  Just push the lower leg of that spring back down, and reinsert the lower cross-pin  (from the left side of the pistol) back into its original position over that spring, as it was originally.

b.  Then, just finish the install according to the instructions below.  You will find normal  function checks at the end of the install procedure will prove installation to be okay.  (These are the normal checks you would perform after any routine cleaning of your pistol.)

6.      Insert HSS into the vacated Mainspring Housing Area in the rear of the handle, below the Lower Cross-Pin.  Note that the HSS is slightly wider than the opening, and must be tilted slightly during insertion through the opening.  Install HSS flat side first (to front of pistol and flush to frame), with HSS narrow end up as shown:

a.      Carefully slide HSS upward along frame to align HSS cross-slot with the Lower Cross-Pin, and with the HSS upper narrow end between pistol’s springs on the left and right side.

7.      Push Lower Cross-Pin to right, through the HSS cross-slot and back to its original position, flush with pistol handle exterior.

         (picture shows Lower Cross-Pin pushed half way back to right.)

8.      Reinstall pistol hand grips.

Hammer strut can never again get caught under cross-pin!

From now on:

1.      With hammer fired (moved to forward position). (Note: MK III must have magazine installed to "fire" hammer.) 

2.      Tilt barrel downward and reinstall Mainspring Housing Assembly Plunger through bolt into pistol Receiver.

3.      With barrel upward, close and secure Mainspring Housing latch.  (Note: will not latch if barrel is not upward.)

4.      You will always feel a "springy" feeling, the last 1/8 inch or so, when pushing the Mainspring Housing Assembly into the handle.  This tells you that the Hammer Strut is properly engaged upon the hammer spring inside the Mainspring Housing Assembly.  The Mainspring Housing Assembly cannot possibly be reinstalled into the pistol incorrectly!!!!!


Important Note:  Any modification of your firearm may void the warranty of the manufacturer.  No liability is expressed or implied for damage or injury as a result of improper installation or use of this product.


HSS Corp;  Santa Rosa Beach, FL         website: HammerStrutSupport.com