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I'm an older (55) but new pistol shooter who has just begun the adventure of NRA Gallery Course competition in our local CPL. We have an indoor league that runs though the fall/winter/spring with 21 weekly events.

Before ever shooting my Ruger KMKIII 512 I installed a Volquartzen sear, trigger and Sam's Mark II style bushing. In dry firing the pistol before the conversion the Ruger trigger pull must have exceeded 5lbs. Pulling the trigger was like chinning oneself with a single finger and on top of that was rough and ragged.

The Volquarzen sear makes a huge reduction in trigger pull as well as making it much smoother. I am bothered by the fact that the pull seems to be highly variable. I would estimate that 80% of the time the pull is on the order of 2.25 to 2.5 lb while about 10% of the time the pull must exceed 3.5 lb and the other 10% of the time the pull seems to be less than the 1lb 2oz that my air pistol requires.

I've run ~ 600 rounds through the pistol at this point and gave it a good cleaning before our meet. During the meet I shot two "flyers" (on the paper but non scoring) that were a direct result of unintentional disharge due to light trigger. Obviously this isn't an acceptable situation from a standpoint of safety or competitiveness.

Any ideas as to the cause of the problem and possible solutions would be greatly appreciated.

Best Regards,

Hugh

Check the pin that goes through the frame that is held by the left grip panel. If that pin is on the short side it will creep out of its hole on the right side and give you fits.

Another possibility is the trigger bushing. It may be oversize and allowing too much variety in how the sear and hammer are mating.

Do a search for the fixes already described here.

FWIW

Stork,

Thanks for the ideas. I'll pull the grips and check the shaft. The bushing is one of the nice ones made by Sam the Canadian. It is a good tight fit so I don't think that it is the problem. In regards to searches, I did several both before and after making my initial post without much luck. Probably just not hitting the right word/words to search for.

Best Regards,

Hugh

Those are all good suggestions to look. I'd also give a look at the sear return spring. This problem sounds like the sear is not seating consistently on the hammer hook. If the spring is bent forward a little bit then this situation could happen.

R,
Bullseye

Bullseye wrote:If the spring is bent forward a little bit then this situation could happen.

R,
Bullseye

Bullseye, Thanks for this additional information. How might one tell if this is the case? would I need to have a second Mark III in hand to compare mine to?

Best Regards,

Hugh

The only real way to check the sear spring is to tear the gun back down. The straight lengths should align with each other. Maybe looking at the sear spring with the hammer out may show if it's bent too.

Other things to check when you have it apart is pin fit, hammer/bushing/pin, and sear/pin. Make sure the sear is not binding in the frame. I would also check to make sure the disconnector is floating properly too before I install the barrel to receiver.

Sam's has a good reputation on his bushings but it's possiable that you have a under size pin giving excess side play. So before you do a detail dissasembly see how much side play you have. Should have little to none.

Like Blue said the legs of the spring should be parallel with each other. Usually what happens is the sear is pushed too far forward during reassembly of a detailed strip and the short leg gets bent a little bit forward. This causes the short leg to lean forward a bit and this causes the sear to not reset on the hammer hook consistently. Look at the picture below.



The Mark I/II/III sear spring legs should align like the ones in the pictures.

R,
Bullseye

What a great combo replies!!!!!!!Between David's description and Bullseye's picture I see how easy this will be to check. A consistent trigger is so important to me right now as my hold improves and scores are rising.

Best Regards,

Hugh