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Why on earth does Mossberg use a one-way screw to hold the safety?

So, I just got done attempting to fit my 590 Shockwave with an NDZ Safety Switch, but while attempting to remove the stock safety, I stripped the stupid tamper-resistant screw.

For reasons which are beyond my comprehension as well as common-sense, Mossberg uses a one-way, tamper resistant screw on a replaceable safety, so when you take it out, you have to tap the screwdriver with a hammer as you rotate the screwdriver in order to make the screw itself turn. Well, I did that, and it felt like the screw was turning just fine, but then suddenly the screwdriver slipped and wouldn't turn anymore. I checked it out and the screw head is deformed just enough that the screwdriver won't engage the head anymore. Never at any point did it feel like I was forcing the screw, it seemed to be turning just fine, then the screws slipped loose and the screw was deformed.
Now, I could just get a larger screwdriver that would fit into the now deformed flat-head slot, but at this point I'm afraid to try out of fear of making it worse and rendering the safety inoperable.

As it stands, the stock safety still works fine, so I'd sooner cut my loses than press my luck. Maybe at some point I'll take it to a gunsmith or something and have them swap it out, but for the moment I don't even want to think about it. Frankly, I'm annoyed at Mossberg for inexplicably using a tamper-resistant, one-way screw on a part that is meant to be replaceable. It should have just been an ordinary screw, then I could have easily removed it, but no.
 
tamper resistant.

I have no idea why.

I guess to deter people from messing with it.
 
Oh well, I just watched a few videos on the subject, and it turns out that it might not be as bad as I thought. The official YouTube Video by NDZ Performance gives pretty terrible instructions and as it turns out, I was doing it wrong as a result. I was just lightly tapping with the hammer because that's what the guy in the video was doing, but apparently you have to hit it it harder so that the screwdriver will bite down into the screw, otherwise it will slip out as it did. The guy in the official video didn't explain that, and was only tapping so lightly because he had already done the prep work prior to the video, which he never really explained, he merely mumbled out in passing that he had already taken the screw out once before.

I'll give it another try tomorrow, hopefully I didn't booger up the screw so badly that it's too late.

For anyone else who may research the subject in the future and happen upon this thread, ignore NDZ's Video, watch this guy instead, he explains it better and does everything on camera.

 
This procedure is similar to removing the anti-theft screws from an automobile lock cylinder. Taking a sharp chisel, the outside of the screw head is engaged in a CCW rotation with the chisel "digging" into the screw and turning it out as it is tapped. A sharp punch can also be used to "dig" into the tamper-proof screw for removal.
 
I gave it another try this morning, but got absolutely nowhere so I quit. I'll call my LGS in a couple days and ask if they have a gunsmith (or anyone who can remove a boogered up one-way safety screw) on hand who can replace it for me. Because although the safety os still operational, I have even less faith in its longevity now that I've gone and messed up the screw holding it in place.

All the stupid videos I watched and guides I read made it sound so easy, making it out as if all you have to do is take a screwdriver and a hammer, line of the screwdriver between a groove and a bump, then lightly tap the screwdriver with a hammer to get it to bite into the raised surface, then just rotate the screw out as you would any other screw.
Meanwhile, unless something has changed within the past couple of years and Mossberg is using much harder screws, tapping the screwdriver with a hammer does nothing but scratch the surface, and hitting it harder would take a very long time to get it to dig in deep enough to provide adequate seating for the screwdriver to simply rotate it out without practically leaning on it.

For reference, here's a pic of the safety screw...
mossberg-590a1_005.jpg


And here's a pic of the screw on mine now...
IMG_20200125_1405463_rewind.jpg
Not the clearest picture, I know, but you can at least see that it's worse for wear since I got done struggling to remove it. Consider this a cautionary tale of what can happen if you go in unprepared.
 
I had the same problem with my 930 SPX (same safety). Finally, I masked off the receiver on both sides of the safety button to prevent scratching it. Then I used a pair of pliers - long nosed vice grips, if I remember correctly - to grab the sides of the plastic safety button just behind the screw hole and twisted.

As expected, the plastic safety button broke in two right at the screw hole. It was then easy to remove the broken pieces of plastic. With the screw head standing proud of the receiver, it was simple to grab with the pliers and unscrew it.

Be careful not to lose the little plastic plate and the tiny detent ball.

The screw was ruined, but the new safety button came with a torx screw anyway.

When reassembling, use a little dab of grease to hold the detent ball in place.

When I replaced the one on my 500, I had no problem whatsoever. I didn't even need the hammer. With a little pressure, the screw came right out.
 
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Yeah, although I had hoped it wouldn't come to this, I'm most likely going to end up going the same route since I really don't care about breaking the stock safety, nor do I plan on reusing the screw.

But thanks, I had actually been hesitant to do so out of concerns of scratching up the finish, and it had never occurred to me that I could just use masking tape to protect it.
 
If you're having trouble, get a gunsmith to do it.

As others have noted, you need to get a sharp edge to put an indentation into the screw...once it's there you can use a flathead screw driver to get that bugger out. Absolutely a PITA, but well worth it for switching in a more ergonomic safety latch. The stock one just doesn't have good purchase for your thumb.
 
That screw looks well and truly buggered up now, so this advice is too late for the OP, but...

I don't intend this to sound preachy, as this is a lesson I learned the hard way myself. Anyone who wants to do any sort of work on their own guns should go buy a set of gunsmithing screwdrivers. Yes, they are different than the regular screwdrivers you buy at Home Depot. A basic set costs around $40-$50. (Worst case scenario, a proper impact driver with a set gunsmithing bits will cost you about $50.) When I wanted to remove the safety on my Shockwave, I just selected the proper size screwdriver, put it in the slot and pushed firmly while turning. Voila! No hammer, no chisel, no stupid Youtube methods to screw up my firearm. A good set of gunsmithing tools will cost you less than a single trip to the gunsmith (especially if he has to fix something you already messed up by using a hammer and chisel on your gun), plus now you have the right tools to do future work on all of your firearms. You'll be amazed how much easier it is to work on all of your guns without buggering up screws once you have the right tools.

FWIW, here are some clues that the person who filmed a gunsmithing Youtube video is an idiot who is encouraging you to damage your gun and should be summarily ignored:
  • They aren't using gunsmithing tools
  • They tell you to hit a screwdriver with a hammer
  • They are working on a shotgun by sitting on the floor and bracing the stock between their knees
  • They tell you to hit a screwdriver with a hammer
  • The tools they do have look like they were purchased at Dollar General
  • They tell you to hit a screwdriver with a hammer
 
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