S&W 2.0 10mm Red dot flew off and hit me in the head

[Ironworker]

I mounted it according to the directions to the dotted i. Moderate loads 7.6 grs of Power pistol behind a 180gr coated bullet. I've shot heavier loads. I've put 250 rounds through with red dot on it. It flew off and sheared the screws off? How do I get the sheared screws out of the slide?

 

[shell627]

You need a good quality mounting plate try chpws. Com same thing happened to me with me with Glock 19 mos a good plate solved the problem.

 

[Aegis]

You also should use loctite. The CHPWS mounting plate is the way to go..

 

[robertrwalsh]

Getting the sheared screws out may be fun. A correct diameter left-handed drill bit, a drill press and a good drill press vise would do the job. I have also heard of people using a VERY SMALL TIP punch and going in to the broken off screw at a slight angle, off-center to provide force in the correct direction to back the screw out. I am not sure that would work in something that small. Good luck.

 

[STORMINORMAN]

Good thing it wasn't from the draw: you might have been injured...!

Cheers!

 

[WVDeere]

Mine did the exact same thing. Right between the eyes. Sheered the screws and the plastic plate lugs on the adapter plate. Sent it back to Smith and Wesson because it was their screws and plate. They returned it with an entire new slide. Purchased a c and h precision plate and so far so good. Also coincidentally I was having a few feeding issues and a gritty trigger. The new slide seems to have fixed everything. Smooth trigger and so far has been 100% reliable. Just took about 8 weeks


Sent from my iPhone using Tapatalk

 

[Rlg#17]

We have been running optic guns for several years from the manufacturer starting with a G for several years now. Several of those guns have a moderately high round count of 15,000+ and are shot daily during the season.

We actually took an MOS specific operators course to learn how to run them. Lotsa good information from the course, well worth the time and money. During the course there were several failures of mounting the optics. It was recommended, and I have started using just plain clear nail polish for the thread locker, instead of loctite or a similar product. We have seen zero issues with loosening of screws from the plates or optics. AND the screws are easier to remove should you have to replace a battery.

15 in/lbs seems to be the magic number for plate and mount screws. If you don't have a good driver, buy one. The only screws I have broken were my own fault. Not using the driver to attach a cover plate. I sent the slide in, and the screw was removed without incident.

Oem plates work fine for us. We are running several optics now (Holosun) that are direct mount to the slide. No plate needed. That seems the better way to go for sure. Lower height relative to the barrel, and co-witness with stock sights so no need for the garish suppressor height sights used with most optics.

Regards, Rick Gibbs

 

[Hawg Rider]

Another choice for broken screw removals is "Easy Outs", better known as screw/bolt extractors. You can find them at Walmart, Amazon, online, and most hardware stores. Although finding a tiny diameter extractor might take a little searching. A local gunsmith may also be able to help you out. I'm getting ready to purchase and install a Holosun 507C on my M&P 10mm 2.0, so I really appreciate this thread. I'll use blue loctite and minimal torque for the screws. Good luck!

 

[WR Moore]

No idea if the screws loosened prior to shearing. But: with the sight gone, the torque value is off the screws, they might well back out easily if you can turn them. [ I've done the center punch thing to remove much larger bolts but never tried on anything that small. Glue an allen wrench to the end?] The left hand twist drill is an outstanding idea, but you don't want to be doing that free hand. Drill press or mill. If there's someone who does EDM machining in your area, they'd be able to remove the screws and leave the threads.

 

[jschmidt]

You got everything right but screw torque. You can ignore any other advice on this. If the screws sheared off, you over torqued them. Use 18 inch pounds of torque. Definitely no more than 24 inch pounds.

See WR Moore's advice for getting them out.

 

[SoCalDep]

You got everything right but screw torque. You can ignore any other advice on this. If the screws sheared off, you over torqued them. Use 18 inch pounds of torque. Definitely no more than 24 inch pounds.

See WR Moore's advice for getting them out.

OP... If I were you I wouldn't "ignore any other advice", and I'd probably ignore the above referenced post. I hate to be mean, but one of the benefits of the internet and forums is the ability to ask questions and discuss. One of the drawbacks is that anyone, including those who lack knowledge and may be plain wrong and dangerous can respond and it's sometimes hard to tell who is what.

Over-torquing is unlikely (but possibly) the problem. There are many more likely causes. As for actual torque specs, general torque specs vary for material (allow steel vs. the various carbon and stainless steels) and the general published torque specs are often less than those recommended by optic, component, or firearm manufacturers, so I would warn against exceeding those recommendations unless you really know what you are doing. 18 inch pounds exceeds both the recommendations of S&W as well as most optics (with the notable exceptions of the Leupold DeltaPoint Pro (25in/lbs), Aimpoint ACRO (26 in/lbs) and Holosun 509T (20 in/lbs). Recommending to tighten to 24 in/lbs without knowing what optic and mount is absolutely irresponsible.

As for some back story, you can reference this thread which includes my department's method for mounting optics, which has been adopted by dozens of law enforcement agencies and other organizations. It also shows some background of why I not only disagree with jschmdt but think he's dangerous in giving blanket advice without real knowledge.

http://smith-wessonforum.com/smith-...p-2-0-core-shearing-screws.html#post141568839

As for this thread, I'd be curious exactly how the optic was mounted, what threadlocker was used if any, and whether a torque wrench was used and what torque setting. Then we can start to see where problems may have developed. We've only installed seven or eight optics on M&P 10mm guns, and one person who installed their own had it shear. The ones we've done have not had issues but none have a ton of rounds through them.

 

[KrustyShellback]

I used the longer screws in mine with locktite & no issues...... Yet

 

[jschmidt]

OP... If I were you I wouldn't "ignore any other advice", and I'd probably ignore the above referenced post. I hate to be mean, but one of the benefits of the internet and forums is the ability to ask questions and discuss. One of the drawbacks is that anyone, including those who lack knowledge and may be plain wrong and dangerous can respond and it's sometimes hard to tell who is what...

I'm sure there is all kinds of gunsmith mythology about why screws shear, but there is no debate among engineers, fastener makers and SAE. Screws shear due to over tightening or separating forces that exceed the rated shear strength. Or, if they are faulty. The second is ruled out by the weight of the optic. The third by the quality of the maker.

But you are right, I should have mentioned to use the manufacturers recommendation. 18-24 inch pounds is the common optic advice when that number is unknown.

Of course anyone is free to take anyone's advice and we agree that there is a lot of cow poop on the internet. We agree that due diligence is always required. We just don't agree on where that smell is coming from.

 

[S&WIowegan]

Loose screws

I took my 929 revolver to the range a few weeks ago after mounting a red dot on an Allchin mount. After less than 50 rounds every screw in/on the gun was loose except the crane screw. I called a well-known S&W expert and he laughed and recommended Locktite #242 blue. Every screw, including the nose cap, got a little dab of 242 and no more loose screws.

Since the screws are probably made by a vender, I think S&W probably over uses their drill bits until holes are a little too large.

FYI a small tube of Locktite only cost me $11.00.

 

[SoCalDep]

I'm sure there is all kinds of gunsmith mythology about why screws shear, but there is no debate among engineers, fastener makers and SAE. Screws shear due to over tightening or separating forces that exceed the rated shear strength. Or, if they are faulty. The second is ruled out by the weight of the optic. The third by the quality of the maker.

But you are right, I should have mentioned to use the manufacturers recommendation. 18-24 inch pounds is the common optic advice when that number is unknown.

Of course anyone is free to take anyone's advice and we agree that there is a lot of cow poop on the internet. We agree that due diligence is always required. We just don't agree on where that smell is coming from.

And this is where I get frustrated…

"The second" is not ruled out by the weight of the optic. Loose screws that allow the optic to move upon the enormous accelerating forces of the slide produce extremely severe shear forces and that is the most common cause of optic screws shearing. Over-tightening can produce shear but it is much more rare during firing, as the shearing usually occurs during installation, and as I mentioned in the other thread, if the forces are within the elastic deformation range of the material the torsional forces dissipate rapidly.

You're assumptions are wrong and I don't recommend anyone follow your recommendations.

We had this discussion in the other thread and while I don't know your experience or lack thereof since you wouldn't explain yourself in the other thread I'm going to simply be blunt. I'm sorry it's not nice but it needs to be said.

This is based on a pretty extensive amount of experience, tracking of optic performance in training and field use by multiple large law enforcement agencies and consultations with mechanical engineers - I've personally mounted over 300 optics and tracked the details of around 220 of those, which has resulted in some of my recommendations being adopted by optic component manufacturers. You're welcome to your posts… free speech and all, but when it's wrong it's wrong and you are wrong.

 

[FWP]

We've only installed seven or eight optics on M&P 10mm guns, and one person who installed their own had it shear. The ones we've done have not had issues but none have a ton of rounds through them.

Did you use the S&W plastic plate or an aftermarket plate on the 10s?

I used the S&W plastic plate on my 10MM with a 507K. I have less than 100 rounds through it and everything is still tight but I am not impressed with the quality.

After reading about the problems others are having I ordered a CHPWS plate.

 

[Imissedagain]

Any recommendations for a decent quality torque wrench/screwdriver or whatever they are called for sights/scopes and other smithing chores?
I have the big set of Brownells screwdrivers and lotsa sockets.

Thx
RT

Decades ago I broke my Campy Super Record rear derailleur, my C Record front derailleur by over torquing and my right shoulder in a Peloton pileup.
Sad but true.

 

[SoCalDep]

Did you use the S&W plastic plate or an aftermarket plate on the 10s?

I used the S&W plastic plate on my 10MM with a 507K. I have less than 100 rounds through it and everything is still tight but I am not impressed with the quality.

After reading about the problems others are having I ordered a CHPWS plate.

I'm not a huge fan of the factory plastic plates, but that is something we have tracked and they tend to perform just fine as long as the screws stay tight. If the screws come loose then as the optic shifts it very quickly damages the posts.

Of course, this is almost exclusively with 9mm. My department only allows 9mm and .45 for duty use and I know of no one running an M&P .45 with an optic. We only have a few running any type of .45 with an optic (mostly Glocks but at least one Springfield TRP). With the few 10mm's we've mounted I think everyone got a C&H plate.

As for C&H, they have had their issues but overall they are a responsive company and certainly benefit the industry. I haven't had any substantial issues with their M&P plates except one that the RMR wouldn't fit on at all. Could be a manufacturing issue with either or tolerance stacking but the RMR ended up mounting just fine on a factory metal plate.

Overall the C&H plates work well and I purchased two so that I'd have them available in case someone's plate was damaged or they didn't realize they needed plates (not all cops are gun people so sometimes they show up with a pistol and an optic assuming it just goes right on).

My overall favorite M&P plate (for optics they fit) is the factory metal. They seem to have the most consistent fit compared to C&H. I hear Tango Down may be jumping into the M&P market and I like them a lot. I'd be excited to see Forward Controls Design come out with some options as well.

 

[FWP]

Thanks SoCalDep.

 

[Rosco Shooter]

I had a similar occurrence with my M&P 40 CORE. Thank goodness I have access to a skilled gunsmith in Acme, Michigan. He had the stubs out in less than 10 minutes. I cleaned out the holes and reinstalled the optic with a dab of Blue LocTite on on each screw.