how does a magazine disconnect work?

[socalbeachbum]

If a semi-auto pistol has a mag disco, where is it located and how would you bypass it if necessary?

is every make and model different in their method?

My son is giving me his old Ruger P-85 and I think it was built in the years prior to mag discos

showing up. But if it has one, I'd like to disable it.

 

[mgmorden]

The Ruger P-85 doesn't have one.

That said, there isn't a blanket answer. Each pistol that has one can implement them a little differently, so it's very much model specific on how to disable them.

I've disabled them on my Hi Power, Ruger SR9, and a Star Modelo Super. I've also got a S&W SW99 that still has the mag disconnect intact.

 

[Sauer Grapes]

I have a S&W 3904 which has one. Not sure when it was made, but I imagine the gun was made in the 90s. If it's like the rest of the 3rd gen Smiths, it can be removed by taking the rear sight off.
How they work? Hmmm, now you have me curious.
I took one out of my 5906 and it made a noticeable difference. Took it out of my 4006, couldn't discern any difference.
Decided to just leave it in the 3904. It's a carry gun, not a target gun.

 

[CZ9shooter]

They few I have encountered are all of different design. Luckily, most are easily disabled, and re-enabled. Some though, like Ruger Mk pistols, require a bit more work. YouTube is usually a good source of instructional information.

 

[lysanderxiii]

I have a S&W 3904 which has one. Not sure when it was made, but I imagine the gun was made in the 90s. If it's like the rest of the 3rd gen Smiths, it can be removed by taking the rear sight off.
How they work? Hmmm, now you have me curious.
I took one out of my 5906 and it made a noticeable difference. Took it out of my 4006, couldn't discern any difference.
Decided to just leave it in the 3904. It's a carry gun, not a target gun.

It works by a plunger in the slide that pushes the ejector down, and the ejector pushes the disconnector down, thus rendering the trigger inoperative. Inserting the magazine forces the ejector to the up position and holds it there. All the hammer fired S&Ws, going back to the original Model 39, work the same way.

They all work differently, some have more impact on trigger pull than others. The HP-35 design is particularly bothersome, as it prevents the magazine from dropping free.

 

[AlexanderA]

Some though, like Ruger Mk pistols, require a bit more work.

The Ruger Mark III's and IV's have magazine disconnects. You can get rid of this feature, though, by substituting Mark II sears and hammers, or by installing aftermarket parts. There's a lot of "backwards compatibility" there. The later Marks have atrocious factory trigger pulls (5 lbs. or so), and this is partially caused by the magazine disconnect feature. Serious target shooters like to lighten the trigger pull down to the 2 lb. range. This is fairly easily done by the substitution of a few parts.

 

[CZ9shooter]

The Ruger Mark III's and IV's have magazine disconnects. You can get rid of this feature, though, by substituting Mark II sears and hammers, or by installing aftermarket parts. There's a lot of "backwards compatibility" there. The later Marks have atrocious factory trigger pulls (5 lbs. or so), and this is partially caused by the magazine disconnect feature. Serious target shooters like to lighten the trigger pull down to the 2 lb. range. This is fairly easily done by the substitution of a few parts.

Right. It can be done. I have done it with VQ and mkII parts in my 22/45. Had to. First time I pulled the trigger I thought for a minute that the safety was on. It was not.

Anyway, I was just saying that removing and buying and replacing trigger group parts is not as simple as removing an easy to get at part, like say a Bersa 380 where you remove just a small spring, or an sr9 with it's striker block plunger. Both of those can be removed and reinstalled in minutes. Probably under a minute with practice.

The moral of the story is that there is no general answer to how to bypass a mag disconnect. They are all different.

 

[socalbeachbum]

thanks guys. guess I'll review each one on a case by case basis when it comes up for me. You Tube is a great idea

 

[Sunray]

YouTube is not a great idea. Anybody can post any kind of nonsense there. Knowing which pistols have a "mag safety" and not buying it unless it's easily removed, is a great idea.
Mag safeties are a European police idea/requirement. Ruger put 'em in as a CYA after losing a frivolous law suit.
"...HP-35 design is particularly bothersome..." Comes out by removing one wee, tiny, pin in the trigger and taking the plunger and spring out the back of the trigger.

 

[mgmorden]

YouTube is not a great idea. Anybody can post any kind of nonsense there.

The same applies to this forum, but the information is generally good. I've found the same with Youtube. There are a TON of things I've been able to do from gun disassembles to home and auto repairs from watching Youtube. It's a very, very useful tool.

 

[hdwhit]

mgmorden wrote:
The same applies to this forum,...

Amen.

I can't say how many times someone has popped up on the handloading forum asking for a load - rather than following proper load development procedures - and I've been tempted to say something like; 38 Special? 158 grain bullet? Well, 10 grains of Bullseye ought to get you to about 1,200 fps. I haven't gone that far, but I have warned people they don't know whether I'm an ethical person with 40+ years experience with no mishaps or a sadistic lunatic who wants them to injure themselves. Sometimes its not a good idea to get your technical information from the public square where the person talking to you might be the village idiot.

 

[hdwhit]

socalbeachbum wrote:
If a semi-auto pistol has a mag disco, where is it located and how would you bypass it if necessary?

Why are you wanting to do this?

 

[socalbeachbum]

I like knowing the weapon will still function if the mag gets lost, left behind, damaged, etc.

 

[Sauer Grapes]

It works by a plunger in the slide that pushes the ejector down, and the ejector pushes the disconnector down, thus rendering the trigger inoperative. Inserting the magazine forces the ejector to the up position and holds it there. All the hammer fired S&Ws, going back to the original Model 39, work the same way.

They all work differently, some have more impact on trigger pull than others. The HP-35 design is particularly bothersome, as it prevents the magazine from dropping free.

Thanks for the info. I didn't want to be an internet commando and guess at it. lol

 

[beag_nut]

I de-activated the mag-disconnect on a 1924 Czech 24, though it took some metalwork to do so. That feature is one of the most-stupid ever devised.

 

[Deus Machina]

Mag disconnects don't really bother me one way or the other, and I can see when they would be implemented--for police or close-engagement military where the user is likely to be in a position where someone tries to take it.
Outside that, you don't need it.

As for the function, in the Ruger SR9 it's a bar around the striker that stops it from dropping completely. With a magazine inserted, it presses on the extending end of it and pushes it out of the way. Not much to go wrong there, not much to alter the trigger.
For 2nd-gen S&W autos, IIRC, it was a lever that disconnected the trigger from the sear if it wasn't in place.
So some may not change the feel of the trigger much if at all, while some (the Browning Hi-Power) are notorious.

 

[Hurryin' Hoosier]

The one in my Browning Hi Power had some sort of plunger dubisary behind the trigger which pressed on the magazine. I never did get a handle on how it worked. Traded the gun for a Colt Combat Commander 9mm. (1911s I understand!)

 

[lysanderxiii]

The one in my Browning Hi Power had some sort of plunger dubisary behind the trigger which pressed on the magazine. I never did get a handle on how it worked. Traded the gun for a Colt Combat Commander 9mm. (1911s I understand!)

The trigger pushes the trigger lever up which tips the sear lever up in the front and down in the rear to depress the sear. The magazine safety is a plunger, spring loaded to the out position (into the magazine well), which pulls the bottom of the trigger lever back, so the top of the sear lever is ahead of the sear lever, disconnecting the trigger from the sear.

Putting a magazine in depresses the magazine safety plunger and the trigger lever spring pushed the trigger lever back into proper position to lift the sear lever. You can drive out the magazine safety plunger retaining pin and remove the magazine safety, but unfortunately, it leaves a hole in the trigger. (I suppose you can put just the pin back in...)

Around late 1943 - early 1944, the Germans had FN stop putting the magazine safety in HPs, in order the speed/simplify production. These are nice because they do not have a hole in the trigger for the magazine safety plunger retaining pin.