Failure to fire

piasashooter · Post by **piasashooter** » Sat Jul 23, 2011 10:22 pm

I have a Ruger MKIII that has developed a problem. My problem is it will fire a round, eject the empty, load the next round but won't fire. It's like the hammer does not reset, when I pull the trigger nothing happen, just loose slack. It used to do this every once in a while, but is happening more often. I have been using the same ammo as I always do, I have tried thoroughly cleaning the gun. I also tried backing off the adjustment screws in my VQ trigger, allowing for plenty of pretravel and over travel, but the problem still occurs. Any advice is welcome,thanks.

Post by **Bullseye** » Sat Jul 23, 2011 10:34 pm

If your adjustment screws aren't causing the problem then the disconnector maybe obstructed by the side of the receiver tube and not free to rise up properly. Check to see if it is rubbing on the inner right edge of the receiver. Also check the trigger plunger and ensure it is not clogged with blow back residue. Either one of these can cause the symptoms you've described.

R,
Bullseye

blue68f100 · Post by **blue68f100** » Sun Jul 24, 2011 8:59 am

Can you simulate this doing dry fire?

If the disconnector or trigger plunger spring is not it, see if you can determine if the hammer is actually cocking? It very seldom happens but the sear springs may be weak and not catching the hammer. Which should make the gun full auto.

greener · Post by **greener** » Sun Jul 24, 2011 10:30 am

When you back out on the adjustment screws, does the problem not go away or go away and then return? If it's the latter then your adjustment screws are walking in. If you've backed them way out and the problem persists, then the problem is something else.

A slight overadjustment of the pretravel screw will result in the hammer resetting when the bolt is manually retracted,but won't reset when cycled during firing. If you haven't used loctite on the screws you can feel the adjustment screw walking in as you screw by feeling the sear catch. (Been there and had a couple folks on GTO splain to me about loctite.)

I found troubleshooting easier by removing the receiver and reinstalling the mainspring on the grip frame. That way the operation is the same as having the pistol assembled and you can see what's going on inside.

Post by **Bullseye** » Sun Jul 24, 2011 5:45 pm

As Greener said, remove the receiver off the frame if the hammer works normally then the disconnector is likely rubbing on the frame. You can see if it will manually raise up better with just the frame in hand.

R,
Bullseye

blue68f100 · Post by **blue68f100** » Sun Jul 24, 2011 6:08 pm

Make sure you catch the hammer when you pull/squeeze the trigger. If you do not catch it the hammer will over rotate and damage the sear.

piasashooter · Post by **piasashooter** » Mon Jul 25, 2011 5:49 pm

First I just want to say thanks for the replies. The gun has just been cleaned so it is not the trigger plunger. The problem has never gone away after adjusting the screws, so I don't think it is a matter of them moving, plus I used thread lock on them. So I removed the receiver as you guys said, and tried to dry fire it to see of it functions that way. When I installed the mainspring , I pulled the hammer back all the way and it just stayed there, leaving a gap between the hammer hook and sear. I pressed down slightly on the front of the hammer near the hammer hook and the hammer shot forward and hooked the sear like it should. I pulled it back a few more times to try and repeat what happened the first try and some times it would get stuck all the way back and some times it wouldn't. Should it be possible for the hammer to do what it is doing?

blue68f100 · Post by **blue68f100** » Mon Jul 25, 2011 6:21 pm

Check to see if the hammer pin hasn't backed out of the frame. Will need to remove grips for this.

piasashooter · Post by **piasashooter** » Mon Jul 25, 2011 7:32 pm

The hammer pin is in place, I have Houge grips and the rubber is tight against the head of the hammer pin.

greener · Post by **greener** » Mon Jul 25, 2011 9:03 pm

piasashooter wrote:. When I installed the mainspring , I pulled the hammer back all the way and it just stayed there, leaving a gap between the hammer hook and sear. I pressed down slightly on the front of the hammer near the hammer hook and the hammer shot forward and hooked the sear like it should. I pulled it back a few more times to try and repeat what happened the first try and some times it would get stuck all the way back and some times it wouldn't. Should it be possible for the hammer to do what it is doing?

When I set a MKII up without receiver and pull the hammer fully back, it springs forward and is caught by the sear. My MKIII VQ hammer will lock back when pulled fully back. (The Mag safety has been replaced by a Sam Lam bushing). The MKIII functioned flawlessly a week ago.

The hammer shouldn't go as far back from the bolt as it goes back when you push it back manually. Unless somehow the bolt is pushing your hammer too far down, I don't think this is your problem.

blue68f100 · Post by **blue68f100** » Tue Jul 26, 2011 9:06 am

I'm assuming that you did a detail clean. Is by some chance is the bushing moving in the hammer causing binding? I'm assume you have a Clark or Sam's bushing. Was the disconnector FLAT. I had mind one time ended up with a slight bend that caused it to bind along the side of the frame. Once I flattened it out all was good. I think the receiver did not get installed straight and somehow it caused it to bend. Have you checked to see if the main spring plunger is floating cleanly in the main spring housing. Some of these can be pretty rough, once they get dirty they start sticking a little. Does not hurt to oil it every once and a while.

Do you think the hammer sticking is the cause of your problems? Or do you think your over cocking it manually. Did the trigger feel the same when it was over rotated? Is the hammer pin floating smoothly in the bushing?

Just throwing some ideas out while I watch the Hummingbirds (Ruby Reds) feed/fight. We are over cast this morning, 76∘ and the birds are swarming the feeders. Seeing as many as 15 at a time, which is more than normal.

Post by **Bullseye** » Tue Jul 26, 2011 9:46 am

It sounds like your hammer strut is binding in the mainspring housing when the hammer is over cocked. This explains why there is a gap between the hammer an sear. Look at the side od the strut and see if there is a shiny spot where it is rubbing on the housing. You may need to polish the side of the strut to reduce drag and prevent hang ups. It may be a little rough from the production process. A little light filing or stoning it should do the trick.

R,
Bullseye

greener · Post by **greener** » Tue Jul 26, 2011 7:59 pm

Bullseye wrote:It sounds like your hammer strut is binding in the mainspring housing when the hammer is over cocked. This explains why there is a gap between the hammer an sear. Look at the side od the strut and see if there is a shiny spot where it is rubbing on the housing. You may need to polish the side of the strut to reduce drag and prevent hang ups. It may be a little rough from the production process. A little light filing or stoning it should do the trick.

R,
Bullseye

I tried the hammer lock on my MKIII 22/45 w/Sam's bushing. Like the Hunter, it would lock back when over cocked. Maybe that has something to do with the MKIII. Both my MKIII's function flawlessly with the receiver on.

Not sure I have a solution to the original problem. Wonder if a picture of the grip frame with the hammer cocked would help?

piasashooter · Post by **piasashooter** » Sat Jul 30, 2011 12:10 am

I checked on the hammer strut to see if there was any wear on it were it could be binding and it looked fine. I sprayed some CLP in the mainspring to maybe loosen up any gunk that could possibly be in there. I took the gun out today and still had the problem, about every 30-40 rounds it still happens. I hope I can get this figured out.

Post by **Bullseye** » Sat Jul 30, 2011 1:05 am

My next thought is a problem with the mainspring housing. I have seen a few with warped spring housings that cause binding on the mainspring plunger. Do you have another that you could switch into your pistol? That could remove the housing from the equation. Any regular Mark III or Mark II MS Housing will work.

R,
Bullseye