Ruger MKIII, bolt not staying open after last round

greener · Post by **greener** » Sun Aug 13, 2006 6:52 pm

I've noticed that on sometimes the bolt on my Mark III hunter fails to stay open after the last round is fired. I think it may be with just one of the two magazines. I've marked the magazines to find out.

Any idea why this may be happening. I've had the pistol for a couple of months and probably only 4000-5000k rounds.

Post by **Bullseye** » Mon Aug 14, 2006 12:12 pm

If it is just the one magazine, then break it down and give it a good cleaning. Inspect the follower button slot to ensure there is no dragging or burrs slowing down the follower.

If both magazines do this, then you may have some dirt or grit caught in behind the bolt stop lever. Field strip your pistol and take apart your bolt stop assembly. Give all the parts a good cleaning and inspect for chafing on the finish or rub marks on the metal. Deburr anything rubbing. Likely some of that thick shipping preservative is still there and now its begun to harden. Reassemble the pistol.

Hope this helps.

R,
Bullseye

greener · Post by **greener** » Mon Aug 14, 2006 9:43 pm

Thanks for the tip. Didn't see anything obvious in the magazines, so I decided to clean them. One follower had some sticky on it and a bit more grit than the other. Also decided to do a bit of cleaning in the frame. Nothing obvious, but I did find a couple of areas that makes me glad I didn't turn the weapon into MSG Cheek in 1969. I might still be doing pushups if I had.

When I finish I put a round in each magazine, inserted the magazine in the frame and verified that the bolt stop came up when I removed the round. Looks like by the time you get to removing the bolt stop assembly for cleaning, you might as well improve the trigger and a few other things, if I read your detailed strip procedures correctly.

greener · Post by **greener** » Mon Aug 14, 2006 9:45 pm

The longest part or reassembling the Ruger for me is lining up the bolt stop holes in the barrel and frame. Lots of tapping with a mallet. Is there a better way than whaling on the gun with a hammer until it surrenders and lines up?

boomer47 · Post by **boomer47** » Mon Aug 14, 2006 10:43 pm

Greener,

Check out Bullseye's page here and scroll down to a fix involving a 5/16th in. drill bit to line the receiver up. Works like a charm.

http://www.guntalk-online.com/TroubleshootingPage.htm

greener · Post by **greener** » Mon Aug 14, 2006 11:12 pm

Thanks. Just when I thought I'd seen everything on the site, you show me this one. Printed, bookmarked and posted over the workbench.

This is one of the better sites I've seen for getting help. And the company is pretty good, also.

Post by **Bullseye** » Mon Aug 14, 2006 11:24 pm

The company on this forum is definitely great. Plus all the help information comes from the gracious contributions of our membership. That receiver seating trick was an original idea of Boomer's that he submitted when I asked for ideas for the troubleshooting page.

Boomer47, 08Aug2006, 11:12pm, One of the handiest gadgets I've made is to grind a taper on the blind end of a 5/16th in. drill bit and drive it through the bolt stop hole from the top after installing the receiver on a new/tight pistol and having trouble getting it lined up enough to install the mainspring housing/bolt stop. Saves hammering on the housing assy. to get the bolt stop in.

Thanks to everyone here on Guntalk! If we're helping each other out this much with information, imagine what those who come to visit on an occasional basis get from us.

R,
Bullseye

greener · Post by **greener** » Thu Aug 17, 2006 9:46 pm

Cleaning the magazines or the other cleaning I did seems to have solved the problem. At least the bolt stayed open on both magazines. Thanks for the help. One or tother bits of cleaning did the job.

greener · Post by **greener** » Sun Aug 27, 2006 4:13 pm

It's back and the problem is from one magazine. About 80% of the time the will not stay open after the last round on that magazine. If it gets to be a bother, then the easiest thing to do is to replace the magazine.

Post by **Bullseye** » Tue Aug 29, 2006 10:08 pm

There's only a few possibilities for this type of magazine failure. The magazine spring is weak. The follower button is not traveling through the track smoothly.

This is an easy problem to troubleshoot. You can mark the metal body of the magazine with a little silver sharpie marker and then start substituting parts with a known good magazine.

Start with the spring. If the spring from the marked mag fails in the good mag, and the good spring works in the marked body then the spring needs replacing.

If that doesn't reveal the problem then next, swap the entire innards. If the marked magazine fails with the good parts, and the good mag works with the suspect parts, then the magazine body is defective. Closely inspect the magazine body inside and out for any chafing, dents, gouges, or bent/bare metal in the follower button track. Inspect the follower to ensure the button is held securely and not loose in the hole.

Sometimes the button gets loose in the plastic and the top of the button cannot push up the bolt stop upwards properly. If the follower is worn then replace it with a known good part.

The key is to keep swaping parts until the culprit is located, but ensure that little rascal part also fails in a known good magazine before replacing it. Also be sure to keep the suspect defective parts separate from good ones. If you lose track it will throw off your troubleshooting standard and also skew the conclusions for repair.

Hope this helps.

R,
Bullseye