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Sticking sear on Ruger Mark 111

Posted: Sat Aug 30, 2014 5:54 pm
by dougvarrieur
Hi all, Doug Varrieur here...looking forward to getting to know you all :) Bullseye, got a question. I have a Mark 111 stainless hunter about 6 months old. When I bought it new I immediately installed a Majestic Arms speed clean kit and a Mark 11 hammer allowing me to remove the magazine disconnecter. All has been well until today. I'd guess I have 1500 rounds through the gun without issue. Cleaning procedure has been removing the bolt and magazine, cleaning the upper receiver, bolt, firing pin and magazine. While shooting this morning the hammer stopped engaging and all I got was a faint click. I fully stripped the pistol, cleaned and lubed it. I pulled out the guts all the way down but not including the sear..... it was moving freely so I saw no need to pull the pin and mess with the spring. I put the gun back together and shot 100 rounds without issue and After clearing the pipe and removing the magazine I replaced the magazine with an empty one then I unscrewed majestic bolt stop pin and removed the bolt, the gun was cocked. I slipped a small screwdriver into the receiver and raised the disconnecter assembly arm ever so slightly. I pulled the trigger and the hammer fired. Next I broke the gun down and manually put pressure on the back of the hammer emulating the trigger spring, then pulled the trigger to release the sear. I did this several times until it failed once again. I noticed if less pressure was put on the back of the sear the sear would release the hammer...too much pressure and it "may" stick, but not here's my question

Should slight filing be attempted, and if so on which surface...or do you think maybe the sear spring needs replacement....or what? That's all I have for thoughts.

Looking forward to your expertise! Thanks in advance :)

Posted: Sat Aug 30, 2014 5:57 pm
by dougvarrieur
"I noticed if less pressure was put on the back of the sear"

meant "I noticed if less pressure was put on the back of the HAMMER"

Posted: Sun Aug 31, 2014 2:08 pm
by Bullseye
Well Doug,

The first thing to do is determine what is causing the sear to stick? Is the sear really sticking or is the disconnector lever not rising up fully and engaging it?

How does the top front edge of the disconnector look? is it angled upward smoothly and not showing any signs of burrs? Do you have an aftermarket trigger installed (like a VQ target adjustable)? If you push forward on the back side of the trigger when you have the misfire will the sear engage normally? When you remove the bolt and the hammer is cocked, is the metal tab for the disconnector lever touching the edge of the receiver when viewing it from the open end of the receiver?