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Hi, new member here. I have a problem with a MK III KMK512 pistol I gave to my daughter for Christmas. I also gave my son the same pistol. With the problem pistol, the bolt retracts very stiffly and feels very rough. If you lower the bolt down slowly, it will stick or hang up about halfway to battery. Today, we took it out for the first time. I was hoping that it would smooth out after firing a few rounds. We shot CCI Minimags and CCI Velocitors exclusively. Over the course of firing 80 rds, there were repeated stopages. It actually seemed to get worse the more we shot it. I should back up a little and mention that we field stripped the pistol, cleaned and lubed it before shooting it. FWIW, my son's pistol fires and functions 100% and is very nearly as smooth as my 20+ year old MKII. I should also mention that the hammer pin is fully seated in the frame. I am hoping that some of you guys might have a solution, short of sending it back to Ruger. Thanks for any help you can give.

smike308 wrote:Hi, new member here. I have a problem with a MK III KMK512 pistol I gave to my daughter for Christmas. I also gave my son the same pistol. With the problem pistol, the bolt retracts very stiffly and feels very rough. If you lower the bolt down slowly, it will stick or hang up about halfway to battery. Today, we took it out for the first time. I was hoping that it would smooth out after firing a few rounds. We shot CCI Minimags and CCI Velocitors exclusively. Over the course of firing 80 rds, there were repeated stopages. It actually seemed to get worse the more we shot it. I should back up a little and mention that we field stripped the pistol, cleaned and lubed it before shooting it. FWIW, my son's pistol fires and functions 100% and is very nearly as smooth as my 20+ year old MKII. I should also mention that the hammer pin is fully seated in the frame. I am hoping that some of you guys might have a solution, short of sending it back to Ruger. Thanks for any help you can give.

Possibly one of the filler screws in the holes in the reciever to mount a scope rail to, is in to far and dragging on the bolt??????????

bearandoldman, Thanks for the response. I just checked the scope mount screws. There was no interference. I also backed it out just to make sure and the bolt still is rough and sticky as well as hard to retract. Thanks for the idea, I hadn't thought of that possibility.

Take it apart now and reinspect it. By now there should be some witness marks where the problem is. Hopefully it's a file fix from there.

The semi circular end of the recoil spring could also be dragging in the receiver tube. Or the end of the rod is dragging on the recoil spring guide rod. How does the bolt slide in the tube with the recoil spring removed? Is its movement any smoother than before when the spring was installed? Sometimes rotating the rod 180 degrees on the riveted end makes all the difference in smoothness.

R,
Bullseye

Thanks for the tips guys, I'll get a chance to look at it later today. Hopefully the info you have provided leads to a solution. Thanks again.
ms

Have you replaced the hammer? I've had problems with the hammer strut sticking in the top of the hammer, and making the bolt retraction very hard (intermittently). It was a Volquartsen hammer. I replaced the VQ strut with a Ruger one and the problem was solved. Took me a while to find this one.

Steve.

smike308 wrote:Hi, new member here. I have a problem with a MK III KMK512 pistol I gave to my daughter for Christmas. I also gave my son the same pistol. With the problem pistol, the bolt retracts very stiffly and feels very rough. If you lower the bolt down slowly, it will stick or hang up about halfway to battery. Today, we took it out for the first time. I was hoping that it would smooth out after firing a few rounds. We shot CCI Minimags and CCI Velocitors exclusively. Over the course of firing 80 rds, there were repeated stopages. It actually seemed to get worse the more we shot it. I should back up a little and mention that we field stripped the pistol, cleaned and lubed it before shooting it. FWIW, my son's pistol fires and functions 100% and is very nearly as smooth as my 20+ year old MKII. I should also mention that the hammer pin is fully seated in the frame. I am hoping that some of you guys might have a solution, short of sending it back to Ruger. Thanks for any help you can give.

Welcome to Guntalk-Online Steve!


R,
Bullseye

Bullseye wrote:Welcome to Guntalk-Online Steve!


R,
Bullseye

Thanks, and Happy New Year to everyone...

Steve.

On mine, the roll pin that goes cross ways thru the bolt was extended out one side and was gouging the inside of the receiver...
http://www.guntalk-online.com/forum/vie ... ight=#6584
This is the thread about my situation and shows where mine was gouging... yours may be gouging either side... just another thing to look at.
Brent