Home Forums Hunting & Shooting Handguns Ruger MKII - Bolt Not Locking Open After Last Shot - Simple Fix

I recently picked up a Ruger MK II Olympic Team USA model (bottom one in the pic below).




When I shot it, the bolt was not locking to the rear after the last shot. I know that this is not an uncommon problem, but I’d never had it happen to me. Magazines can often be the culprit with MK II malfunctions so I tried several different magazines (about 6 or 7) and the problem remained. I also tried 3 different kinds of ammo, including 40 gr CCI Mini Mags and 40 gr Automatch. I figured if those two aren’t hot enough to fully cycle the bolt, then nothing would be. But, the problem persisted. If you pulled the bolt to the rear on an empty mag it would lock back but never by itself after firing the last shot.

I was a little bummed at this point, because the only other “fixes” I knew were to replace the bolt stop and to check the face of the bolt for damage. I stripped down the gun and looked at the bolt and the bolt stop. Both seemed OK to my untrained eye. I gave the gun a routine cleaning and headed back to the range. (Our indoor range is 5 minutes from my house and is open 24/7. Each member has a key code to get in.) (Sidetone: The seller of the gun said he cleaned and lubed with Frog Lube. I cringed, because I knew he didn’t shoot it much, which meant the Frog Lube had been sitting for a long period of time. For those that haven’t had the pleasure of using Frog Lube (aka Frog Glue) it turns to thick sticky paste after sitting for a long time on your gun. It gets mostly outstanding reviews from people who clean and lube a gun with it and then write the review 10 minutes later, but do NOT use it as a long term lubricant. It’s in the same league as WD 40 as a long term gun care product. Also do not mix it with any oil based products.) Anyhoo, I shot some more with various magazine/ammo combinations, but it was still the same.

I got back online and was going to order a bolt stop assembly when I read a post from another forum that said that sometimes gunk builds up between the bolt stop and the frame of the gun. It gets gritty and slows the movement of the bolt stop just enough that it doesn’t lift quick enough to catch the bolt on the last shot. I thought that seemed a little far fetched, but I figured I’d give it a try before ordering new parts. There was, in fact, a bit of gunk there (more Frog Lube) but not that much. I cleaned it out and went over to the range for some more test firing. Well, that did it. Every ammo from every magazine functioned perfectly.

I posted this, because most results from Google searches will lead you to either take the gun to a gunsmith or install a new bolt stop assembly right off. Try cleaning the unexposed side of the bolt stop assembly first. It might save you some grief.

Carry on.

Good to know.

Thanks!

I thought the MK II never locked open after the last shot, all other models do.

The bolt doesn't stay open after the last shot on my Ruger Standard, either. (Oh well, don't think it is supposed to!).

Mike

MK II's are designed to lock open after the last round.

I stand corrected, the Mark I and standard don't lock open after last shot...

may be a magazine problem also causing your problem.

Did you read Wader's whole post? Like this part..

Agreed!