Why did my optic shear off?

[WAYNO]

There are hideous stresses on slide mounted optics.

The market is red hot, and the manufacturers are doing their best to design and market their optics systems as quickly as possible, just hoping their engineering will be good enough for the long haul.

When a fastener is torqued against a compressible spacer, one cannot expect the torque value to remain constant, and with as much force and vibration as there is with slide mounted optics, the weak link will do its best to present itself. Further, it is unreasonable to me to expect shear forces to be contained only by itty-bitty fasteners,

 

[Xmark1]

There are hideous stresses on slide mounted optics.

The market is red hot, and the manufacturers are doing their best to design and market their optics systems as quickly as possible, just hoping their engineering will be good enough for the long haul.

When a fastener is torqued against a compressible spacer, one cannot expect the torque value to remain constant, and with as much force and vibration as there is with slide mounted optics, the weak link will do its best to present itself. Further, it is unreasonable to me to expect shear forces to be contained only by itty-bitty fasteners,

I think you nailed it!

 

[Certaindeaf]

I'm no engineer or anything but about everything will throw off torque values.. adapters, extensions, grease, thread lock, and perhaps plastic spacers. Maybe them puny fasteners were over-torqued and snapped?

 

[thorborg]

My T3 tikka came with plastic trigger guard. I kept having trouble keeping the receiver tight as each time I torqued it down the screws would compress the plastic a little more and eventually loosen the receiver. finally the front screw had entered so far it dragged on the bolt, I temporarily fixed the problem by JB welding a steel ferrule and thin aircraft stainless washer for the screw head to push on. Later, bought a metal trigger guard with added benefit of a larger, more rectangle, opening, fitting a gloved finger much better. It now stays to the torque I demand.
Beware of plastic where torqued things are important to stay tight.

 

[ferret427]

My guess would be that if 9mm will blow someone's lungs out their back, imagine the extra stress imparted to your slide with that extra 1mm of bullet diameter...result: your sight flies off. Go back to 9mm. Lungs will still be blown out, but your optic will not fly off your gun and give you scope bite that will cause your friends to laugh at you for weeks. Hope this helps.

 

[spookshack]

S&W: Our plastic plates are adequately strong enough for 10mm.

10mm: Hold my beer…..

 

[Xmark1]

My guess would be that if 9mm will blow someone's lungs out their back, imagine the extra stress imparted to your slide with that extra 1mm of bullet diameter...result: your sight flies off. Go back to 9mm. Lungs will still be blown out, but your optic will not fly off your gun and give you scope bite that will cause your friends to laugh at you for weeks. Hope this helps.

Yea. I love 9 for two legged predators but bears on my Wa property require a 10. A full power 10 has about twice the horsepower of a 9.

 

[Xmark1]

I'm no engineer or anything but about everything will throw off torque values.. adapters, extensions, grease, thread lock, and perhaps plastic spacers. Maybe them puny fasteners were over-torqued and snapped?

I agree that the fasteners are puny! The recoil from a 10mm bear load is substantial.

 

[Koda]

Ive always felt the two mounting screws on my Trijicon RMRs to be too small, but they hold fine, including my 10mm. But mine are also mounted directly to the slide with no adapter plate. I notice the fit is also tight with just the slide cutout it feels like they snap into place, even without the screws in yet. I suppose it doesnt take much thread engagement when mounted direct, especially on a Glock slide where one of the two screws has to be even shorter to not interfere with the extractor. But I do worry that if say the gun was dropped, the screws would break if the RMR took a direct hit. All said, I cant fathom the idea of a plastic adapter plate now.

 

[Certaindeaf]

It'd be interesting to see a pic of the uninstalled plastic spacer. It looks like they took the time to machine two perfect round nubs to ostensibly mate with the optic, which if then was negated by a plastic shim would then be.. janky.

 

[FishinKings]

Yesterday, while shooting my S&W M&P 2.0 4.6 in barreled 10MM, My Holosun optic flew off and hit me in the face.
The two attachments screws/bolts just sheared off - see attached pictures.
I was shooting 180 grain projo's at 1,250 FPS.
I used the plastic adaptor plate that came with the pistol at time of purchase.
I also used the screws provided by S&W.
the screws were torqued to proper spec with blue Loctite.

Is there anyone that has knowledge or experience as to why this happened?

I can only imagine the joy involved in getting the broken studs out of my slide.

View attachment 1980546 View attachment 1980547 View attachment 1980548 View attachment 1980549 View attachment 1980554

I had the same thing happen to me after mounting a SwampFox on my 4.6 10mm with the S&W plastic Zev plate. After mounting the optic I put 300 to 500 rounds of 180 gr round nose through the gun with no problems. I then bought 4 boxes of Underwood 220gr Hardcast, some where on box #2 the screws sheared off, the optic struck me above the right eye cutting my forehead.

Ive always felt the two mounting screws on my Trijicon RMRs to be too small, but they hold fine, including my 10mm. But mine are also mounted directly to the slide with no adapter plate. I notice the fit is also tight with just the slide cutout it feels like they snap into place, even without the screws in yet. I suppose it doesnt take much thread engagement when mounted direct, especially on a Glock slide where one of the two screws has to be even shorter to not interfere with the extractor. But I do worry that if say the gun was dropped, the screws would break if the RMR took a direct hit. All said, I cant fathom the idea of a plastic adapter plate now.

View attachment 1980686

Yesterday, while shooting my S&W M&P 2.0 4.6 in barreled 10MM, My Holosun optic flew off and hit me in the face.
The two attachments screws/bolts just sheared off - see attached pictures.
I was shooting 180 grain projo's at 1,250 FPS.
I used the plastic adaptor plate that came with the pistol at time of purchase.
I also used the screws provided by S&W.
the screws were torqued to proper spec with blue Loctite.

Is there anyone that has knowledge or experience as to why this happened?

I can only imagine the joy involved in getting the broken studs out of my slide.

View attachment 1980546 View attachment 1980547 View attachment 1980548 View attachment 1980549 View attachment 1980554

I had the samething happen to me after mounting a Swampfox with the S&W plastic Zev plate. After mounting the optic I put three to five hundred rounds of 180gr round nose through it with no problems.
I then bought four boxes of Underwood 220gr Hardcast, halfway through box #2 the optic sheared off, striking me above the right eye cutting my forehead. The round post on the plastic Zev plate had sheared off. I called S&W and they asked me to send in the slide, they sent me back the slide after removing the screws, the return was about six weeks, no charge. Thank you S&W.

I then bought a Holosun 509t and a CH Plate, I had a Holosun 407c so I bought a plate for it as well, just in case the 509t was to big. The CH plate for the 509t was a press in fit, the plate for the 407c was about five thousands too small and a loose fit. The gun had a hard time processing the Underwood 220gr so at the same time I bought a heavier return spring and heavier mag springs, as well as polishing the feed ramp. I ran two hundred rounds of 180gr round nose and 20 rounds of Underwood through the gun, the optic held, it still had problems with the Underwood. I then installed a Apex Extractor and fired 50 rounds of 180gr and 40 rounds of Underwood 220gr without a hiccup. After installing the Apex Extractor I took out the heavier return spring and replaced it with the stock spring, leaving in the heavier mag springs, I then shot a magazine of 180gr and another 20 rounds of Underwood 220gr without a problem. I am confident and happy with this setup. The Underwood 220gr Hardcast hit with Conviction!

 

[Stomper]

Yesterday, while shooting my S&W M&P 2.0 4.6 in barreled 10MM, My Holosun optic flew off and hit me in the face.
The two attachments screws/bolts just sheared off - see attached pictures.
I was shooting 180 grain projo's at 1,250 FPS.
I used the plastic adaptor plate that came with the pistol at time of purchase.
I also used the screws provided by S&W.
the screws were torqued to proper spec with blue Loctite.

Is there anyone that has knowledge or experience as to why this happened?

I can only imagine the joy involved in getting the broken studs out of my slide.

View attachment 1980546 View attachment 1980547 View attachment 1980548 View attachment 1980549 View attachment 1980554

OMG, your Holosun optic actually flew off and hit you in the face?!



Is the Holosun OK?

 

[spookshack]

So a Holosun and a P320 walk into a bar…..

Before they even have a chance to order their beers, the bartender looks at them and says, "I'm not serving you two!" As they turn to each other to say WTF, the bartender looks right at Holosun and says, "if you get too many beers in you, you'll just end up flying off the handle!" He then proceeds to tell P320 that "if you get too many beers in you, you'll end up falling of your barstool and just pop off for no reason at all!"

 

[Xmark1]

It'd be interesting to see a pic of the uninstalled plastic spacer. It looks like they took the time to machine two perfect round nubs to ostensibly mate with the optic, which if then was negated by a plastic shim would then be.. janky.

Here Ya go!

 

[Xmark1]

I had the same thing happen to me after mounting a SwampFox on my 4.6 10mm with the S&W plastic Zev plate. After mounting the optic I put 300 to 500 rounds of 180 gr round nose through the gun with no problems. I then bought 4 boxes of Underwood 220gr Hardcast, some where on box #2 the screws sheared off, the optic struck me above the right eye cutting my forehead.



I had the samething happen to me after mounting a Swampfox with the S&W plastic Zev plate. After mounting the optic I put three to five hundred rounds of 180gr round nose through it with no problems.
I then bought four boxes of Underwood 220gr Hardcast, halfway through box #2 the optic sheared off, striking me above the right eye cutting my forehead. The round post on the plastic Zev plate had sheared off. I called S&W and they asked me to send in the slide, they sent me back the slide after removing the screws, the return was about six weeks, no charge. Thank you S&W.

I then bought a Holosun 509t and a CH Plate, I had a Holosun 407c so I bought a plate for it as well, just in case the 509t was to big. The CH plate for the 509t was a press in fit, the plate for the 407c was about five thousands too small and a loose fit. The gun had a hard time processing the Underwood 220gr so at the same time I bought a heavier return spring and heavier mag springs, as well as polishing the feed ramp. I ran two hundred rounds of 180gr round nose and 20 rounds of Underwood through the gun, the optic held, it still had problems with the Underwood. I then installed a Apex Extractor and fired 50 rounds of 180gr and 40 rounds of Underwood 220gr without a hiccup. After installing the Apex Extractor I took out the heavier return spring and replaced it with the stock spring, leaving in the heavier mag springs, I then shot a magazine of 180gr and another 20 rounds of Underwood 220gr without a problem. I am confident and happy with this setup. The Underwood 220gr Hardcast hit with Conviction!

I appreciate the info from someone who had a similar problem.
However, it was my left eye that got hit.
Good thing I always wear eye protection!

 

[Xmark1]

I had the same thing happen to me after mounting a SwampFox on my 4.6 10mm with the S&W plastic Zev plate. After mounting the optic I put 300 to 500 rounds of 180 gr round nose through the gun with no problems. I then bought 4 boxes of Underwood 220gr Hardcast, some where on box #2 the screws sheared off, the optic struck me above the right eye cutting my forehead.



I had the samething happen to me after mounting a Swampfox with the S&W plastic Zev plate. After mounting the optic I put three to five hundred rounds of 180gr round nose through it with no problems.
I then bought four boxes of Underwood 220gr Hardcast, halfway through box #2 the optic sheared off, striking me above the right eye cutting my forehead. The round post on the plastic Zev plate had sheared off. I called S&W and they asked me to send in the slide, they sent me back the slide after removing the screws, the return was about six weeks, no charge. Thank you S&W.

I then bought a Holosun 509t and a CH Plate, I had a Holosun 407c so I bought a plate for it as well, just in case the 509t was to big. The CH plate for the 509t was a press in fit, the plate for the 407c was about five thousands too small and a loose fit. The gun had a hard time processing the Underwood 220gr so at the same time I bought a heavier return spring and heavier mag springs, as well as polishing the feed ramp. I ran two hundred rounds of 180gr round nose and 20 rounds of Underwood through the gun, the optic held, it still had problems with the Underwood. I then installed a Apex Extractor and fired 50 rounds of 180gr and 40 rounds of Underwood 220gr without a hiccup. After installing the Apex Extractor I took out the heavier return spring and replaced it with the stock spring, leaving in the heavier mag springs, I then shot a magazine of 180gr and another 20 rounds of Underwood 220gr without a problem. I am confident and happy with this setup. The Underwood 220gr Hardcast hit with Conviction!

P.S. not all 180's are the same. for example, S&B 180's clock @ 1,100 fps.

Did you notice my 180 handloads clock at 1,250+. BIG difference in recoil!

As you know, your underwood's are extreme! Much recoil!

 

[Xmark1]

OMG, your Holosun optic actually flew off and hit you in the face?!



Is the Holosun OK?

My first thoughts exactly, Lol.
At first, I thought I got hit by an eject.
I upped my recoil spring, so my cases don't land in a different zip code.
Because of the increased power spring, I sometimes get hit with an eject.
Yes, my brand new Holosun did not even get a scratch!

 

[spookshack]

Here Ya go!

View attachment 1980776View attachment 1980777

Damn, that plate has " diabetic" written all over it……

 

[Saladfarmer]

 

[spookshack]

View attachment 1980784

I was trying hard to work him into my reply. Well done sir.