To MOS or not to MOS

mrtoyz · Jan 8, 2023

Yes I know, MOS has a horrible reputation. Ive never actually met anyone that’s had a problem but hear plenty of people say how bad they “heard” it was…
Here’s my situation: I have multiple Glocks that I’d like to add dots too. One of which is a rare 21SF pic rail. I’d originally thought about the Agency AOS system. Lots of flexibility, great option. Then I started thinking about the fact that it doesn’t look like MOS is going away and there are companies offering much better plates now. I do like that I could used Glock filler plates if I choose not to run a dot or sell one in the future. Should I stay true to Glock and do MOS cuts or go a different direction?
Oh I’ll be running RMR’s, 509’s and EPS’s

redneckbmxer24 · Jan 8, 2023

With MOS you’re a plate away from swapping optics if something better comes along or you just end up not liking what it’s cut for. There’s absolutely no issue with the MOS system with a quality plate like the FCD. The Glock plates however are trash.

owtlaw · Jan 8, 2023

Www.thecncpros.com offers excellent plates for the Glock MOS.

DairyDictator · Jan 8, 2023

I had multiple problems with the MOS POS. Screws backing out even after blue loctite, plates not being flat, losing zero, etc. Never again. Went to a shadow systems (yes I know, not in the same price bracket) and their mounting system is seriously impressive. Worth noting, those adapter plates are cast, not machined from billet. No thanks.

Plate swapping for an optic doesn't do anything for me. RMR footprint has all the options I need in a red dot. RMR/SRO for reliability, Holosun for BS cheap fun.

If something new comes out and proves itself (AKRO platform looks interesting), I'll get another slide and have it milled. Dealing with 3 threads max of screw engagement on tiny screws for the life of the firearm just so you can swap optics if you see something shiny is a fucking stupid compromise if you ask me.

Maybe aftermarket plates will yield better results, but at the end of the day you're still stuck with 2 sets of screws to come loose, one of which isn't even accessible to paint mark and check, and a few threads of engagement in thin material. I'd rather spend the money and get a lower sitting red dot that cowitnesses with regular sights, and a much more reliable mounting solution.

Pappasniper · Jan 8, 2023

I would consider just buying another slide so you can keep you Glocks whole like your 21SF. It may be a Glock slide or another brand that is very nice. I sold a bunch of guns and bought them optics ready, before slide where an option in another brand. Wish Had waited because the finances are the about same. I lost my butt on the selling and buying.

PB

mewillis · Jan 9, 2023

I just got a G34.5 MOS, no optic yet but Holosun (not a fan and don't own) has an MOS only green/red dot and solar powered no battery. I'm seriously contemplating one but can't quite make the move yet. I did fondle one and it seems robust. It even has different modes for dot/dot circle etc.

SCS MOS Red-Holosun

**Coming Soon** The SCS-MOS (Solar Charging Sight) is a direct attachment optic for GLOCK MOS systems offering the lowest profile deck height for use with standard-height iron sights. The SCS-MOS combines solar power, rechargeable power storage, with an auto-adjusting reticle brightness to...

www.holosun.com

MAGnificient · Jan 10, 2023

If you want to keep your Glocks whole like your 21SF, I'd think about just purchasing another slide.

CSTactical · Jan 10, 2023

The MOS system is ok when you're not 100% sure what optic you want to keep their permanently. I've had the ACRO P1 and a ~~Holosun~~ 509T right now that will be replaced with a P2, Sig Romeo2, Holosun EPS (I hope not LOL) or if something better comes out at Shot.

Forrest · Jan 18, 2023

I just bought a new gen3 Glock 20sf. I'm in CA that's all we are allowed to buy. I bought a new Lone Wolf g20L long slide and a KKm 6" barrel for it. I was going to send the slide to CH and have a MOS cut done to it. I had planned on shooting hot loads with it. After reading about screw problems I'm having second thoughts. I might have a picatinny rail machined in place of a MOS cut.

pineoak · Jan 18, 2023

Consider getting it milled/refinished for the optic you want. Spend more, but do it right.

Not based on experience, but what I've read from people that have started "easy" and ended up doing the hard way in the end.

Like the people that buy a $400 rifle, a $1000 rifle, and end up with a custom or AI.

b6graham · Jan 18, 2023

Forrest said:
I just bought a new gen3 Glock 20sf. I'm in CA that's all we are allowed to buy. I bought a new Lone Wolf g20L long slide and a KKm 6" barrel for it. I was going to send the slide to CH and have a MOS cut done to it. I had planned on shooting hot loads with it. After reading about screw problems I'm having second thoughts. I might have a picatinny rail machined in place of a MOS cut.

might wanna read about CH before you send anything of value to them

Anb618 · Jan 18, 2023

Get the slide direct milled. New slide if you want to be able to keep your 21SF resale value.

b6graham said:
might wanna read about CH before you send anything of value to them

I sent my 365XMacro to them for a direct RMRcc cut in December. They did good work and had it back in under 4 weeks. Their Black Friday sale was a great deal. No complaints.

HOOFER · Jan 18, 2023

They make aftermarket plates that remove any concern

G45 MOS. With new titanium holosun

Forrest · Jan 18, 2023

b6graham said:
might wanna read about CH before you send anything of value to them

Will do thanks. Lone Wolf also does slide machining for optics,

Forrest · Jan 18, 2023

Anb618 said:
Get the slide direct milled. New slide if you want to be able to keep your 21SF resale value.

I sent my 365XMacro to them for a direct RMRcc cut in December. They did good work and had it back in under 4 weeks. Their Black Friday sale was a great deal. No complaints.

I did buy another slide to cut up so I don't have to alter the factory G20 slide. It's a long slide

Leftie · Jan 18, 2023

I've heard extremely good things about the FCD MOS plates, specifically for the ACRO footprint.

A buddy of mine has over 6k rounds through his with an ACRO P2 on a G19 MOS slide and has had no issues with the ACRO P2, nor with the FCD mounting plate. That being said, it's 9x19mm which isn't exactly 10mm pressures, and he's shooting mostly 124s through it that are standard pressure. On occasion it might get 124 or 147 +P, but the majority are 124 FMJs at standard pressure.

I think that the real questions here as others have mentioned are the following:

~~- Do you want to direct mill your factory slide?~~
- Are you comfortable with milling a slide and having a single specific footprint moving forward (absent any conversion plates)?
- Would you ever want to change optics reasonably easily?

CSTactical · Jan 18, 2023

Leftie said:
I've heard extremely good things about the FCD MOS plates, specifically for the ACRO footprint.

A buddy of mine has over 6k rounds through his with an ACRO P2 on a G19 MOS slide and has had no issues with the ACRO P2, nor with the FCD mounting plate. That being said, it's 9x19mm which isn't exactly 10mm pressures, and he's shooting mostly 124s through it that are standard pressure. On occasion it might get 124 or 147 +P, but the majority are 124 FMJs at standard pressure.

I think that the real questions here as others have mentioned are the following:

~~- Do you want to direct mill your factory slide?~~
- Are you comfortable with milling a slide and having a single specific footprint moving forward (absent any conversion plates)?
- Would you ever want to change optics reasonably easily?

I had an ACRO P1 with a FCD plate (Still have the plate) and the plate is fantastic, in fact I had a conversation with them today about a Sig Romeo2 plate which will be in the future at some point. So I've decided on the ACRO P2 for the replacement above if it comes in before FCD makes a Romeo2 plate.

LawnMM · Jan 18, 2023

You can get an MOS gun, but buy somebody else's plates. The MOS plates are plastic, they don't fill any space between the optic and slide body so all the sheer force is on the screws and the MOS screws are small.

They break, a lot. Screws, plates, all of it. Just buy a CH plate or an FCD plate for the optic you want and use that instead and you're good to go.

RKBArmory · Jan 21, 2023

We just received, into our shop, the first Holosun SCS for Glock MOS, that has come through here. I am impressed that there is an optic made specifically for the Glock MOS, and no plates are needed. It sits low enough to use normal sights, and has three different reticle options. This is a significant development in favor of the MOS.

Lightly Used $262.49.

mrtoyz · Jan 21, 2023

HOOFER said:
They make aftermarket plates that remove any concern

G45 MOS. With new titanium holosun

I’ve been hearing this. If true it does make the most sense IMO.
While milling for the exact optic is best it make it so hard as new tech comes out.

CSTactical · Jan 21, 2023

Forrest said:
Will do thanks. Lone Wolf also does slide machining for optics,

The only companies I trust to cut my slide is ATEi, Jagerworks and Maple Leaf at this time.
No affiliation with any of these companies, they have proven themselves consistently over the years.

mrtoyz · Jan 21, 2023

CSTactical said:
The only companies I trust to cut my slide is ATei, Jagerworks and Maple Leaf at this time.
No affiliation with any of these companies, they have proven themselves consistently over the years.

Doesn’t look like they will cut just the MOS pattern. Think I’ll reach out to see if they will

CSTactical · Jan 21, 2023

mrtoyz said:
Doesn’t look like they will cut just the MOS pattern. Think I’ll reach out to see if they will

Unfortunately there is not enough material left.

Forrest · Jan 21, 2023

CSTactical said:
The only companies I trust to cut my slide is ATei, Jagerworks and Maple Leaf at this time.
No affiliation with any of these companies, they have proven themselves consistently over the years.

Thanks for the information.

CSTactical said:
Unfortunately there is not enough material left.

Maple Leaf’s site FAQ section answered one of my questions. Why isn’t a Glock MOS cut offered forward of the rear sight dovetail cut on a standard non MOS slide? “The rear dovetail sight cut on a Glock factory MOS slide is father to the rear of the slide. This is because if you try and do a MOS cut on a standard slide with the rear sight dovetail cut remaining in place the MOS cut will go too far forward and into the safety cavity machined in the slide.

mrtoyz · Jan 21, 2023

CSTactical said:
Unfortunately there is not enough material left.

Confused. Wouldn’t there have to be enough material, in that MOS slides do have the material. Not aware of a difference in MOS vs non MOS slides.
Looks like CHPWS does the MOS cut for non MOS slides.

mrtoyz · Jan 21, 2023

Forrest said:
Thanks for the information.

Maple Leaf’s site FAQ section answered one of my questions. Why isn’t a Glock MOS cut offered forward of the rear sight dovetail cut on a standard non MOS slide? “The rear dovetail sight cut on a Glock factory MOS slide is father to the rear of the slide. This is because if you try and do a MOS cut on a standard slide with the rear sight dovetail cut remaining in place the MOS cut will go too far forward and into the safety cavity machined in the slide.

Ahhhh this is good info.
@CSTactical is this the material you’re talking about?

CSTactical · Jan 21, 2023

mrtoyz said:
Confused. Wouldn’t there have to be enough material, in that MOS slides do have the material. Not aware of a difference in MOS vs non MOS slides.
Looks like CHPWS does the MOS cut for non MOS slides.

I thought you meant to cut an MOS slide to a specific optic pattern like an RMR, ACRO , etc...

mrtoyz · Jan 21, 2023

CSTactical said:
I thought you meant to cut an MOS slide to a specific optic pattern like an RMR, ACRO , etc...

Forrest · Jan 21, 2023

mrtoyz said:
Confused. Wouldn’t there have to be enough material, in that MOS slides do have the material. Not aware of a difference in MOS vs non MOS slides.
Looks like CHPWS does the MOS cut for non MOS slides.

The rear sight on a Glock Factory MOS slide is machined farther to the rear to make more room for the MOS cut in front of it.

Forrest · Jan 21, 2023

From Maple Leaf site FAQ:

Converting non-MOS slide to MOS footprint.

Non-MOS slides cannot be safely machined to accept the Glock MOS footprint. This is due to the location of the rear iron sight dovetail relative to the drop safety mechanism.

Factory MOS slides have the rear dovetail positioned further back than dovetails found on non-MOS slides, allowing more distance between the rear sight and the drop safety mechanism for the relatively long MOS footprint to fit.

mrtoyz · Jan 21, 2023

Forrest said:
From Maple Leaf site FAQ:

Converting non-MOS slide to MOS footprint.

Non-MOS slides cannot be safely machined to accept the Glock MOS footprint. This is due to the location of the rear iron sight dovetail relative to the drop safety mechanism.

Factory MOS slides have the rear dovetail positioned further back than dovetails found on non-MOS slides, allowing more distance between the rear sight and the drop safety mechanism for the relatively long MOS footprint to fit.

Interesting. Assuming CHPWS is accomplishing their MOS cut in a non MOS slide by eliminating the rear site and sling rearward?? Need to find pics.

Forrest · Jan 21, 2023

mrtoyz said:
Interesting. Assuming CHPWS is accomplishing their MOS cut in a non MOS slide by eliminating the rear site and sling rearward?? Need to find pics.

That would be my guess. Nobody else seems to offer the MOS cut.

CSTactical · Jan 21, 2023

I would not go out of my way to get the MOS cut, I'd prefer to go to Agency and get their AOS cut.

Forrest · Jan 21, 2023

CSTactical said:
I would not go out of my way to get the MOS cut, I'd prefer to go to Agency and get their AOS cut.

I want a cut but don't want to be locked into one specific sight or small group of sights. So is there an option? Agency doesn't offer cutting service for Glock 20 or 21 slides

CSTactical · Jan 21, 2023

Forrest said:
I want a cut but don't want to be locked into one specific sight or small group of sights. So is there an option? Agency doesn't offer cutting service for Glock 20 or 21 slides

They tend to make their system for the optics that matter outside of all the Holosun options https://www.agencyarms.com/agency-optic-system-aos-cut

I may send off one of my Gen 3's to get an AOS cut which is supposedly superior to the MOS system according to many I trust including Aaron Cohen of Sage Dynamics.

Forrest · Jan 21, 2023

CSTactical said:
They tend to make their system for the optics that matter outside of all the Holosun options https://www.agencyarms.com/agency-optic-system-aos-cut

I may send off one of my Gen 3's to get an AOS cut which is supposedly superior to the MOS system according to many I trust including Aaron Cohen of Sage Dynamics.

Still leaves me out I have G20L slide and they don't list G20 or G21 on their drop down choices.

CSTactical · Jan 21, 2023

Holy crap, I forgot that they can mill around the MOS system!

Slides with factory optic systems or aftermarket optic cuts will have minor remnants of the previous cut.

mrtoyz · Jan 21, 2023

IMO opinion the AOS system is about as good as it gets. My thought had been tho that it’s a 3rd party platform that could disappear (I know not likely) so why not duplicate the MOS as it doesn’t appear to be going anywhere and is working well with after market plates.
Like @Forrest i have a 20 and 21 I’d like to do a well. CHWPS seems to have the MOS solution however you loose the rear site.

owtlaw · Jan 22, 2023

I had Www.thecncpros.com cut my non MOS slide with an MOS cut.

Just Macca · Jan 22, 2023

Another spanner in the works and maybe of interest..

Radian have just announced their mount plates which significantly strengthen the MOS system (both mounting and physical protection). Available for RMR and Holosun EPS.

CSTactical · Jan 22, 2023

Just Macca said:
Another spanner in the works and maybe of interest..

Radian have just announced their mount plates which significantly strengthen the MOS system (both mounting and physical protection). Available for RMR and Holosun EPS.

View attachment 8054239

View attachment 8054238

Another option, I’m going to check that out…

Forrest · Jan 24, 2023

mrtoyz said:
IMO opinion the AOS system is about as good as it gets. My thought had been tho that it’s a 3rd party platform that could disappear (I know not likely) so why not duplicate the MOS as it doesn’t appear to be going anywhere and is working well with after market plates.
Like @Forrest i have a 20 and 21 I’d like to do a well. CHWPS seems to have the MOS solution however you loose the rear site.

I decided to send my Lone Wolf G20 long slide back to LW and have them machine it to their “Slide melt” Trijicon RMR cut. The RMR cut will allow a few other optics to be mounted, but I’m going with a Trijicon. The rear sight cut will be retained.

Watch Out for Scammers!

To MOS or not to MOS

Armchair Commando

Four Star General

Private

Unlucky Bastard

Sergeant

Sergeant

Banhammer

Sniper's Hide Vendor

Supporter

Attachments

Assistant Minion

MMPRL

In Valor, there is Hope.

Sergeant

Attachments

Supporter

Attachments

Supporter

Attachments

Sergeant of the Hide

Sniper's Hide Vendor

Harbinger of Sarcasm

We Buy & Sell Quality Used Optics

Armchair Commando

Sniper's Hide Vendor

Armchair Commando

Sniper's Hide Vendor

Supporter

Armchair Commando

Armchair Commando

Sniper's Hide Vendor

Armchair Commando

Supporter

Supporter

Armchair Commando

Supporter

Sniper's Hide Vendor

Supporter

Sniper's Hide Vendor

Supporter

Sniper's Hide Vendor

Armchair Commando

Private

Mealteam 6

Sniper's Hide Vendor

Supporter

I decided to send my Lone Wolf G20 long slide back to LW and have them machine it to their “Slide melt” Trijicon RMR cut. The RMR cut will allow a few other optics to be mounted, but I’m going with a Trijicon. The rear sight cut will be retained.​

Similar threads

I decided to send my Lone Wolf G20 long slide back to LW and have them machine it to their “Slide melt” Trijicon RMR cut. The RMR cut will allow a few other optics to be mounted, but I’m going with a Trijicon. The rear sight cut will be retained.