Total MKII Mystery

[EVR]

With some ammo, not all, the magazine partially ejects when the last round is fired.

I disassembled the magazine catch, replaced the mag catch spring and also removed a little metal off the mag catch tail allowing more spring tension on the magazine catch, but it still did it 4 times when shooting cheap lead bullet loads {Win & Fed}. About 300 rounds were fired.

So it has improved, but is not 100% reliable. Any ideas?

This is a bizarre "malfunction" as I cannot see any reason it would occur. NO I'm not bumping the mag catch. It also appears to occur more often when I'm shooting one-handed.

Now, your turn....

 

[EVR]

Well, 400 rounds later...

I think I got it.

The mag catch is a fairly massive thing and, on the way beck from the range {range is 3/4 mile form the house in a ravine on the ranch} I wondered...

And slapped the butt of the pistol on my hand and voila...mag popped.

I guess on the last round there is enough slop in the mag and enough intertia in the mag catch and if I am shooting "hard" {shot backed up by bone, not limpwristed, the mag is released.

I think the solution is to skeletonize the thing. I do not have a proper mill machine but do have a RIGID drill press in the shop. Maybe I could drill a hole in the mag catch big enough to remove enough material to reduce the mass enough to solve this thing? Gonna try.

 

[rugerguy]

when you say "MK II" are you asking about the bottom ,European style catch or the 22/45 left side of the frame thumb release???
we see issues with wear on the front edge of the bottom style mag release, or it gets rounded off (some we've seen filed down...)just make sure the notch is "square" to the bottom of the magazine,and engages it properly..it should NOT "bounce" out of position & release...have you tried other magazines?? not sure what you mean by "skeletonize".....you remove too much material ,you will make it "lighter"??(less mass, easier to move, "bounce" off???) hhhmmmm...........

 

[tek4260]

Try loading 9 instead of 10 in the mag. Maybe a full mag has too much spring compression and is keeping the mag from seating fully?

 

[EVR]

when you say "MK II" are you asking about the bottom ,European style catch or the 22/45 left side of the frame thumb release???
we see issues with wear on the front edge of the bottom style mag release, or it gets rounded off (some we've seen filed down...)just make sure the notch is "square" to the bottom of the magazine,and engages it properly..it should NOT "bounce" out of position & release...have you tried other magazines?? not sure what you mean by "skeletonize".....you remove too much material ,you will make it "lighter"??(less mass, easier to move, "bounce" off???) hhhmmmm...........

Yes, I got t figured out.

Weird, too.

The mass of the mag latch allows enough "bounce" as you say to release the mag. The situation only occurs when the mag is emptied, that is, on the last shot. My 6" bbl gun doesn't do it {more gun mass I suppose} but my 4" does.

I am certain a HARD magazine latch spring would cure the problem but they are all pretty weak. I got several from Ruger and cannot find a supplier of stronger ones. Yeah, it is strange.

Downward pressure of the actual mag spring as when the mag is loaded and the gun firing causes enough friction to preclude the occurence. It is when the magazine is empty {-ied} on the last shot that it occurs.

 

[Pinecone]

EVR, You can "bend" the legs of the mag latch spring slightly to increase the tension on the latch. Shooting one-handed puts more of the felt recoil on the latch and gun in general than when shooting two handed. That's why you see the difference in the malfunction one handed. I would try another mag as suggested above to see if you get the same symptoms. A process of elimination will get you to the "exact" cause!......................Dick :wink:

 

[EVR]

Thanks for all the replies.

The mag latch spring is weak, way weaker than I'd like.

I think it is the mass of the latch itself. I have a few coming and will lighten one as much as I can and see if that works.

 

[Rick Courtright]

I think it is the mass of the latch itself. I have a few coming and will lighten one as much as I can and see if that works.

Hi,

Question time: is this a pretty "low mileage" gun?

Following your "adventures" it seems there are too many things that say if it were mine, my first thought would be "It needs to wear in" rather than "Let's start changing stuff."

Now, there well COULD be some problems that need some 'smithing of either the kitchen table or professional nature.

But before doing that, have you done a "fluff and buff" of all the affected areas?

The extractor may need to be deburred a bit (or replaced w/ a VQ unit if you'd prefer), the slot it rides in may need deburring, as may the hole the spring and plunger ride in. On reassembly, a TINY bit of oil should be used: these parts don't like to run dry but too much will collect crud.

The mag catch may need to be deburred, and a tiny drop of oil where it rides on the pivot pin won't hurt.

The mags can have rough edges, 'specially in the slot the little follower button rides in. They can have crud, direct from the factory or self-created from shooting, that needs to be cleaned out. The springs should have just a touch of oil on them to prevent corrosion but that's about all.

The bolt should be inspected for rough areas, cleaned well, and lubricated VERY lightly. Again, the crud problem can pop up if over done.

Any place you find a spring & plunger combo, inspect, clean the hole and lube sparingly.

And if the gun's got fewer than a couple thousand rounds, it may be a "tight" one that just needs to be shot in more.

Not sure if any of those will help, but, in the words of my old gunsmith boss, "First let's get it working the way Ruger intended before trying to make it work they way you want... you may be surprised!" I've said it before, but in our shop Rugers were considered "kit guns": "Buy one, bring it to us, and we'll finish it for you!" Most of that "finishing" was simply fluff and buff...

Even if none of the above works, it'll give you some peace of mind to know it's been done and some of the "usual suspects" have been dealt with.

Good luck!

Rick C

 

[EVR]

Rick;

Good questions.

We have 3 of these; 2 MKII's and one "MKI"/Standard. Have had all for years.

Only one is a bugger, the 4".

Thousands of rounds thru it. Not sure how many.

Extr spring is noticeably lighter than on the others. Extractor has no burrs, etc, and tho I bought spares I'll just keep it. Will try replacing the spring tho.

As for the mag latch, it is just a bugger. Not that the problem is catastrophic in any way, since it only occurs when the last round is fired. But I still don't like it. 6 mags, and 2 are the worst offenders, others less so. No obvious problems with the mags themselves.

Latch fits well and functions/swings, has a good "claw" but still releases. I'll monkey with another and see if I can cure it.

 

[Rick Courtright]

We have 3 of these; 2 MKII's and one "MKI"/Standard. Have had all for years.

Only one is a bugger, the 4".

Thousands of rounds thru it. Not sure how many.

Hi, EVR

Ok, that shoots the "need to shoot it more" idea, doesn't it?

Thinking cap's been put away for the day, but the mag catch still has me intrigued, as I've yet to see a Mk-series w/ that bottom latch being a problem child. But I should defer to Dan (rugrguy) and Pinecone there: they probably see more of 'em in a couple of months than I have in my whole life!

One thing does come to mind. You mentioned the claw being good. How about the holes the pin goes thru. Are they nice and round, or have they wallowed out a bit w/ use? Or is the pin worn enough to create the same effect? Just thinking out loud until I can go unlock mine and look at it, but I'm wondering if some wear at that point, unnoticed probably, might affect the angle the claw sits at on the bottom of the mag, allowing it to "slip" easier than the others?

One cheap and dirty way to figure out if it is the mag latch would be to swap the "bad" one w/ one from one of your "good" guns. You may be rapidly getting to that "single variable" approach to troubleshooting, and that could tell you if the problem's in the latch itself or somewhere else...

You've got me curious now!

Rick C

 

[Bullseye57]

I know this is an older thread but it sounds to me as if the magazine latch spring is in backwards. If this is the case the tension is too weak and will inadvertently release the magazine. It should be oriented with the loop facing forward on the cross pin like the one shown below.

R,
Bullseye