SP101 Locking Up

[Black Fly]

I noted this down in the RugerSmithing area where it only got a few comments, and wondered if there might be more comments here on the Revolver Forum. I had this problem with my SP 357 4.2 inch, sent it back to Ruger, it came back and I am again having the problem. When you operate the gun in single action, if you pull the hammer back part way, and don't reach full cock, the gun locks up. I can give the cylinder a little nudge and it's fine. It never happens on double action, and only on occaission in single action. I've cleaned it pretty thoroughly and it still happens. I'm probably going to call Customer Service, but am curious how common this is, and if you've had the problem, how have you fixed it.
For me this has become my favorite and love to shoot and carry it.
Thanks
Bfly

 

[VAdoublegunner]

I have noticed this happening from time to time on DA revolvers. It is not a solid lock up, but seems to be certain mating surfaces being in hard contact where they would otherwise slide on past that particular engagement point in normal operation at normal operational speeds. I thought with Rugers in particular it may have something to do with timing and the hammer plunger/dog and bolt engagement relation. But I also have a Smith that can do it if you carefully manipulate the hammer almost to full cock then let it back down slowly. A little nudge of the cylinder or recocking the hammer releases it.

Plenty of lube in the right place seems to help, perhaps a light polish job on some of the mating surfaces. I have polished them up with a good whitening toothpaste, a very mild abrasive, that smooths them up nicely. I've even heard of squirting the action full of toothpaste and working it for a while, then complete disassembly and cleaning up.

But I think if you are working to get them to hang up, the old Doc's advice from HeeHaw is best prescribed here...."Well, don't do that!"

edit/ Found this online "how to" if you are interested in playing around with it yourself.
http://www.teslamap.com/public/sp101_trigger_job/index.html

 

[Black Fly]

Yeah, if it hurts don't do that? After I reviewed my post I figured that was coming, and deserved it. I'd insert a smiley face if they were available. The problem really doesn't bother me, that much. But I was curious. When I get home, I'll have to try my S&W Performance Center gun, to see if it's there. I might give the tooth paste polishing a go. It's always amazing how much smoother Rugers get with some use.
Thanks
Bfly

 

[Jimbo357mag]

Take a look at the teeth on the cylinder ratchet and the way the pawl works on them. I had one tooth that needed to be touched up with a small file. :D

 

[Carry_Up]

How embarrassing that the factory itself cannot address their own service issues! I can't believe those who say simply ignore it, it works most of the time. The revolver has a problem and it should be fixed. Several revolvers I have seen have this problem, but it can be caused by a number of things.

Sometimes the cylinder will hang up because there is insufficient headspace. I recently examined a GP100 with only .002" of headspace. The case rims just could not rotate freely against the recoil face. Some revolvers have insufficient b/c gap - less than .003". After a few shots, the metal will expand, locking the cylinder to the barrel. After cooling down, the revolver will work normally.

The current problem happens in DA mode only, so the cylinder lock is not the problem. There is most likely a burr in the hammer/trigger engagement area because in DA the hammer is lifted by the trigger, while in SA the hammer pulls the trigger. I would look first at the hammer DA paul - the spring loaded lever on the front of the hammer.

Just a few thoughts. Don't file or stone until you actually see the problem or identify it using felt marker. You might also offer to sell the factory the fix after you find the problem. Sounds like they could use a little help.

-cu