MOS Plate issues.

[ricardo28]

So I work in a swat team that was authorized red dots on their duty pistols just over a year ago and I am the primary armor. I personally shot over 12,000 rounds through a G17.5 with an Aimpoint Acro with a steel plate in the last year. Most of the guys I work with opted to get the Holosun 509T. I wanted to share some issues we have had as I see a few posts on plates. I also happen to mess around in my garage which is a machine shop so know a bit about tolerances and material. Ill primarily be focusing on these two optic plates above and especially the 509 plates.

 

I AM NOT NAMING COMPANIES but many of the plates are garbage.

 

First, Material; do not be fooled by the name of most plates, the material does matter. 6061 alum is garbage especially when thinned out to around .07" in the web where the lug meets. I have seen several popular vendors who appear to utilize the same manufacturer as their plates have the exact specs and even look the same. But each vendor uses a different name for the plate. Many of these plates have bent or lost the shape when the screws are torqued to 13-15in/lb. Some have even come in already bent due to the 6061 aluminum being too thin even for the packaging or shipping. The manufacturer has no idea of reinforcing critical areas as it is farmed out to the lowest bidder, likely china.  6061 will lose its shape if you take the optic off once or twice and retighten it.

 

Second, screws; The glock uses a 2.5-.45 thread screw. Many are 6-8mm long depending on the plate thickness. These screws are garbage after a single use and please replace the screw if you remove them. I have had to drill out and clean up several threads from people reusing the screws. Often times, companies ship short screws to prevent any issues which itself causes issues of only a few threads catching and not having enough engagement. *** I order screws from McMaster Carr or other companies who have US made parts***

 

Third, Dimensions; The MOS cut is just over 1.9305" long. the width is not as important but is 1.0025". Most of the optic plates I have measured are well under 1.925 and usually closer to 1.92" This does not seem like much but when you combine a small screw with the energy of recoil and the weight of the optic, you will destroy the screws. I have found some optics loose and once taken off the pistol, found a screw sheared off. Having a properly fit plate that is snug in the MOS cut will prevent any recoil force from breaking the screws. The screw holes should only be holding the plate down, not putting the energy of the recoil into the screws.

 

The Holosun 509t has a dimension that I believe is important. The front of the optic has a radius of 2.8188" and the lower lug that engages the plate is only .03" deep. Luckily the 509 also has the dovetail to help hold it in place but that lower lug is not very deep. Ensuring the front radius and the lug are dimensionally correct and contact the plate at the same time is important in my opinion.  This distributes the energy through the optic and ensures it is not put into one time spot on the optic. Unfortunately some of the plates I have mounted for guys were not correct in this dimension. 

 

All of the plates I have seen or put on myself are sloppy, Every one, even the steel plates. They fit like crap. 

 

Learning from all our issues, I thought it would be a waste to have machines in my garage and have made several plates for friends that are in my opinion, superior to any MOS offerings so far. Wasted some material as my machines are Manual and I learned a lot but well worth my time. 

[JBP55]

Are you offering these plates and correct screws in the market place?

[BHBret]

Does one of this apply to the factory Glock MOS plates?

Edited August 23, 2021 by BHBret
Punctuation error

[ricardo28]

1 hour ago, BHBret said:

Does one of this apply to the factory Glock MOS plates?

I have not seen a factory plate for the Acro or the 509T but the plates they do offer do not secure the optics by anything other than the screws. They are also loose in the cut.

[Cuz]

Damn, another rant about MOS plate issues without a solution.

 

So far I think that buying a slide milled for RMR from Brownells for my 3rd gen Glock was a better solution that any of the plates I've tried on my MOS Glocks.

 

[ricardo28]

1 hour ago, JBP55 said:

Are you offering these plates and correct screws in the market place?

I do not have any production other than one here and there. If I do produce more in the future, I will look into selling on here.

[ricardo28]

2 minutes ago, Cuz said:

Damn, another rant about MOS plate issues without a solution.

 

So far I think that buying a slide milled for RMR from Brownells for my 3rd gen Glock was a better solution that any of the plates I've tried on my MOS Glocks.

 

If your sticking with the RMR, I would seriously look at a company that does the cut or grab a slide that is already cut. IMO, the RMR has fallen behind and I know more than a few people who have moved away from the RMR to the ACRO and 509T. Enclosed emitter, View thru the glass..... really should look at enclosed emitters that solve a lot of the issues the RMR has.

[ltdmstr]

C&H PWS is the way to go when it comes to aftermarket MOS plates.  Their V4 LEO plates are top quality in every way.

Edited August 24, 2021 by ltdmstr

[ricardo28]

25 minutes ago, ltdmstr said:

C&H PWS is the way to go when it comes to aftermarket MOS plates.  Their V4 LEO plates are top quality in every way.

Straight from their site, 6061 alum. It is also the exact same, machining and measurements as another company who put, "Steel" on the plate despite it being 6061. I believe they both source it from the same manufacturer. If you like it, then I am glad. That plate also drops in and has slop from front to back. There are several complaints on this website about that plate. I have seen several from both companies fail, bend, come in bent, and are super thin in the web.

 

Do a test, put just the plate on, dont use the screws. slide the plate forward and backwards. You will find it has no contact at the front or back. I would also bet when the screws are tightened, there is a gap at the front. This places all the recoil to the screws. 

Edited August 24, 2021 by ricardo28

[Dirty_J]

C&H has had some suuuuuper sketch QC in recent times. 
 

Allegedly turned it around… but those parts never should have reached the marketplace. 

Edited August 24, 2021 by Dirty_J

[ltdmstr]

Well, I've used several C&H plates for RMR and Holosun and none had any slop or other issues.  Fit was near perfect on every one. I'd be surprised if the Acro or other plates were any different.  I suppose they could have screwed up and produced a bad batch.  But I'd be surprised if they didn't stand behind the product and replace any that weren't right.  As for bending, stripped threads, etc., the only instances I've seen were due to improper installation.

[Cuz]

5 minutes ago, Dirty_J said:

C&H has had some suuuuuper sketch QC in recent times. 
 

Allegedly turned it around… but those parts never should have reached the marketplace. 

I have had absolutely no luck with any of their plates. I have 3 and regret them all. The screw and T-nut system results in a screw that is so thin and weak it can barely hold itself up. 

[Southpaw]

Interesting write up based on I'd imagine some hard use testing. Have you tried any of the Forward Controls Design plates for RMR and ACRO? They claim to have much tighter fit than other plates.

 

Of plates you've tried which do you recommend for 509t?

[Cuz]

2 hours ago, ricardo28 said:

If your sticking with the RMR, I would seriously look at a company that does the cut or grab a slide that is already cut. IMO, the RMR has fallen behind and I know more than a few people who have moved away from the RMR to the ACRO and 509T. Enclosed emitter, View thru the glass..... really should look at enclosed emitters that solve a lot of the issues the RMR has.

Ricardo, 

my angle is strictly competition and range toys. I haven’t yet bought into red dots on carry/house/protection firearms. I’m relatively new to red dots on pistols and am still feeling them out. I like shooting the Trijicon SRO, and also have Holosuns on less used pistols.  I really do enjoy the Holosun 510C on my PCC, but once again, it’s a range toy. I’m not ready to trust Holosun with my personal safety yet. 

[ricardo28]

46 minutes ago, Southpaw said:

Interesting write up based on I'd imagine some hard use testing. Have you tried any of the Forward Controls Design plates for RMR and ACRO? They claim to have much tighter fit than other plates.

 

Of plates you've tried which do you recommend for 509t?

Of the several plates I have seen tested, I would not recommend a single one for the 509T which is why I started making them for some of the guys I know. Forward Control Design used Tango Down ACRO plate which I have used and it is fine, made of steel, but still has that little wiggle room that I do not like. Their RMR plate is the typical design with the two screws holding it down then the two small lugs helping the screws with recoil.

Edited August 24, 2021 by ricardo28

[ricardo28]

45 minutes ago, Cuz said:

Ricardo, 

my angle is strictly competition and range toys. I haven’t yet bought into red dots on carry/house/protection firearms. I’m relatively new to red dots on pistols and am still feeling them out. I like shooting the Trijicon SRO, and also have Holosuns on less used pistols.  I really do enjoy the Holosun 510C on my PCC, but once again, it’s a range toy. I’m not ready to trust Holosun with my personal safety yet. 

I didnt like Holosun at first but in my opinion, they have proven themselves more than some pistol optic companies. I havent shot much CO division but shot it a ton in training. Still a single stack guy. 

[ricardo28]

54 minutes ago, ltdmstr said:

Well, I've used several C&H plates for RMR and Holosun and none had any slop or other issues.  Fit was near perfect on every one. I'd be surprised if the Acro or other plates were any different.  I suppose they could have screwed up and produced a bad batch.  But I'd be surprised if they didn't stand behind the product and replace any that weren't right.  As for bending, stripped threads, etc., the only instances I've seen were due to improper installation.

I would be willing to bet that if you did the test I stated above, you would change your mind about their fit. Simply look at how thin the web is where the optic lug goes. I assure you, it is very flimsy. I have seen several plates over the last year and they were all the same. Or if you dont want to take the optic off, put a feeler gauge between the front and back of the plate. If your plate is perfect, then you got an anomaly. 

 

When you have no contact at the front and back of the plate, all the recoil goes to the screws. Screws fail when shear force is applied (Recoil), they are far stronger in the direction they are meant to be used. 

[Cuz]

The simple fact of the matter is that the whole “plate” concept is great from the gun Mfg side. They make one system that anyone can buy and use whatever red dot you want because they give you 4 “free” mounting plates to use. It’s also a win for probably 75% of the people that buy them, because some of them will never even mount a red dot on their gun, they just wanted the option to. The rest of that group will mount an optic, do a less than average job sighting it in, and then proceed to shoot less than 100 rounds a year through the gun. Heck, I have one each of the above categories and the MOS system will be fine on those guns. 
 

I even sent a slide out to have the MOS cut milled into it so that I could use my existing plates to play with multiple optics. This was before I realized how dumb that idea was. I had the opportunity to mill the slide for a specific optic and it would have been a nice solid mount, and I blew it. I half blame the gunsmith for not even suggesting that I might be making a mistake. 
 

Then there’s the rest of the folks who use their guns hard whether it be for work or pleasure. The MOS system does not hold up well in this category. They would be better off getting a traditional slide and milling it for a specific optic, but that is a bit more expensive. 

[Rolex]

My G43X was cut for the Holosun 407k x2- has had 2k rounds through it- no issues.

My G48 MOS-has the same dot with a CH plate- so far- with 500 rounds through it

its still good to go- it will have more use in the next few months with training- 

[ricardo28]

Recently swapped a plate for one of the guys I work with. He was using a very popular plate, Same plate sold by two different companies but with different names. It did fit tight in the MOS pocket but, that was after filing the length down as it was a good bit over 1.93". Here are some comparison pics of what I'm talking about. Look how thick the black plate is at the web/ Lug and front relief. This has caused several plates bend prior to arrival or during install due to the length being to long. I also made the plate to support the back of the optic. 

 

The few plates I have made for friends are from 6al-4v Titanium. This allows me to have nearly 4x the strength of the 6061 plate and keep the low weight compared to an all steel plate. Not only is the Titanium stronger than alum, having the thin areas reinforced also adds to the rigidity. I also do not need a special coating which will add to the dimensions. I anodize the titanium which keeps the dimensions the same as I machined them to but also adds a layer or protection to the plate even though Titanium already very corrosion resistant, anodizing adds a slightly harder surface.

Edited August 29, 2021 by ricardo28

[Llando88]

Good info.

 

I am new to dots, .civ shooter. I have two HS507c's installed on two Glocks, both with Forward Controls OPF-G, RMR plates.   The FC plate fit is snug and tight.  I followed the install process using blue/medium threadlocker, OEM screws/FC screws and a Wheeler FAT wrench to 13 in/lbs.  Round counts are low, but no problems to date, FWIW.

 

HS 507c #0641
Pistol: G34 MOS
Rounds: 902 rounds

HS 507c #1867
Pistol: G19 MOS
Rounds: 160 rounds

Edited August 29, 2021 by Llando88
spell out FC

[Hvansky]

CHP!!!!!

[Intheshaw1]

1 hour ago, Hvansky said:

CHP!!!!!

Dang man, what are you trying to sell....

[SGT_Schultz]

On 8/23/2021 at 8:28 PM, ricardo28 said:

IMO, the RMR has fallen behind and I know more than a few people who have moved away from the RMR to the ACRO and 509T. Enclosed emitter, View thru the glass..... really should look at enclosed emitters that solve a lot of the issues the RMR has.

The RMR has not fallen behind in durability nor in the excellence of its auto brightness adjustment, the two things that matter most to me.

 

Closed emitter optics bring nothing to the table for personal protection and sport applications.

 

Maybe they're swell for police use. I'll have to take your word for it.

[Boomstick303]

On 8/23/2021 at 7:28 PM, ricardo28 said:

IMO, the RMR has fallen behind and I know more than a few people who have moved away from the RMR to the ACRO

 

Not sure exactly in what way they fell behind when so many are trying to copy them. As far as a self defense dot I choose an RMR. They have been the most robust optic for years now after the release of the Gen 2 units. Until an ACRO can come up with a reasonable battery life for an optic I would not be choosing one of those.  I do think Holosun are good optic but I do not rank them with an RMR. Many people chase the flavor of the week so it does not surprise me that people have moved off RMRs. But it most likely had zero to do with the performance of the optic. 

 

While I do see the benefits of a closed RDS, I have yet to see one that makes sense for a pistol. Most fall short in way or another of the RMR. Until one comes along that checks all the boxes I will keep my RMR. 

 

For competition is use a mix of SROs and Romeo 3 optics for the large glass size. If I felt I needed a more durable optic they would all be RMRs. 

Edited October 17, 2021 by Boomstick303