If you are reading this article then you are likely a fan of Arex. The Slovennian manufacturer has built a reputation for building some sweet pistols. One of their latest striker fired models is the Arex Delta Gen 2. The Gen 2 comes in three different variants, the L, M, and the X.
The Gen 2 can also be purchased with an Optics Ready slide. If you have an Arex Delta Gen 2 L,M, or X with an Optics Ready (OR) slide then we are going to tell you which Holosun Red Dot and Green Dot Sights will fit on it with no modification needed and which Optics Plates you need to use for each.
Quick Nav
- Pistols this article applies to
- Holosun Optics we recommend for the Arex Delta Gen 2
- Holosun vs other brands
- What Optics Footprint is the Arex Delta Gen 2?
- Best Holosun Optics for RMR Plate Type 2
- Holosun 407C - Best Budget Option
- Holosun 507C - Best All Around Option
- Holosun 507C ACSS Vulcan - Best Specialty Option
- Holosun 508T - Most Durable Open Emitter
- Holosun 509 ACSS Vulcan - Best Specialty Closed Emitter
- Holosun 509T - Most Durable Closed Emitter
- Holosun 507 Comp - Best Competition Optic
- Best Holosun Optics for Modified RMSc Plate Type 5
- Holosun EPS - Largest Window with Lowest Deck Height
- Holosun 407K - Best Budget Option
- Holosun 507K - Best All Around Option
- Holosun 507K ACSS Vulcan - Best Specialty Option
- Holosun EPS Carry - Best Closed Emitter Option
- How to choose between red or green reticles
- How to decide which reticle style is best for you
- Conclusion
Which Arex Delta Gen 2 models does this apply to?
- Arex Delta Gen.2 L Optics Ready Slide (OR)
- Arex Delta Gen.2 M Optics Ready Slide (OR)
- Arex Delta Gen.2 X Optics Ready Slide (OR)
- Arex Delta Gen.2 Tactical
Which Holosun Optics do we recommend for the Arex Delta Gen 2?
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Using Plate Type 2: |
Using Plate Type 5: |
Why do we recommend the Holosun Optics vs other options?
- They are a good combination of high quality and affordability.
- They have the longest battery life and batteries can be changed without removing the optic.
- They come in red & green reticles with different sizes and styles.
- They are strong with 7075 aluminum or titanium housings and glass.
- They have convenient features like Shake Awake, easy to press brightness buttons, and Side Mounted Batteries.
- Some models have Solar Panels which will power the optic if the battery dies.
- They have a Limited Lifetime Warranty.
- They are reliable, water proof, and have a great track record
When you compare them to other options like Leupold, Trijicon, Crimson Trace, Burris, Bushnell, Aimpoint or others you will find the Holosun’s are more affordable or have more features, longer battery life, and a proven track record with millions of optics sold in the last 10+ years.
What optics footprint is the Arex Delta Gen 2?
When mounting optics to a pistol the first thing you need to know is the Optics Footprint. Each Red Dot Sight has a different mounting pattern. Luckily the smart folks at Arex did a great job with the Delta Gen 2 Optics Ready. They give you 5 different optic plates, each plate lets you mount different optics.
The Arex Delta Gen 2 features a proprietary cut slide and then comes with 5 optic mounting plates which you then attach to the slide. You will then attach the red dot of your choosing to the optic plate. In this case we are going to use the Type 5 Plate (Modified RMSc Footprint) or the Type 2 Plate (RMR Footprint).
Type 5 Plate (Modified RMSc) vs Type 2 Plate (RMR) Optics
Below we are going to break down which Holosun optics you can put on the Arex Delta Gen 2 by plate type.
- Type 2 Plate (RMR) optics: These are going to be larger, they will be wider with a slight overhang on the slide, they’ll have slightly larger windows, and will be a bit heavier. They will also mostly all come with solar panels and auto brightness and manual brightness settings.
- Type 5 Plate (Modified RMSc) Optics: These are going to be smaller in size, will have slightly smaller windows, will likely sit flush to the slide with no overhang, will be a little lighter, and will mostly not come with solar panels or auto brightness modes.
Best Arex Delta Gen 2 Holosun Optics (Type 2 Plate RMR Footprint) - Larger Optics
Below are the best RMR footprint Holosun red and green dot sights you can mount on your Arex Delta Gen 2. These all have an RMR footprint so use the “Type 2” mounting plate that comes with the Arex Delta Gen 2.
1. Holosun 407C Green & Red Dot - Best Budget Option
Buy the 407C At The Best Price
The most budget friendly option is going to be the 407C. The 407C has a 2 MOA dot only. The housing is aluminum.
If you are ok with having just a 2 MOA dot all the time, then the 407C is a great option.
It has shake awake, a side removable battery, solar failsafe with auto brightness or manual brightness modes, 10 daylight and 2 nightvision settings, and is IP67 waterproof.
Read our full 407C review here.
2. Holosun 507C Green & Red Dot - Best All Around Option
Buy the 507C At The Best Price
The Holosun 507C is very similar to the 407C except it has Holosun "MRS" reticle.
It's available in Red or Green reticles and the MRS (Multi Reticle System) lets you use a 32 MOA ring + 2 MOA dot, or it can be toggled to show only the 32 MOA Ring or just the 2 MOA dot by holding down the "-" button for 3 seconds.
It has shake awake, a side removable battery, solar failsafe with auto brightness or manual brightness modes, 10 daylight and 2 nightvision settings, and is IP67 waterproof.
Read our full 507C review here.
3. Holosun 507C ACSS Vulcan Green & Red Dot - Best Specialty Option
Buy the 507C ACSS Vulcan At The Best Price
The 507C ACSS Vulcan may pique your interest. It's just like the 507C except is has the ACSS Vulcan reticle. This reticle features a 250 MOA Ring and a 10 MOA chevron - sounds crazy right? Well it's crazy awesome! It helps new red dot shooter and experts alike, and allows for the most precision out of all optics mentioned here.
You can learn more about the ACSS reticle here but to summarize, the 250 MOA Ring helps you find the center dot quickly if you are off center and the 10 MOA chevron acts like a BDC reticle and also has a very precise point for precision work.
It's available in Red or Green reticles and if you wanted to turn the outside ring off you can by holding down the "-" button for 3 seconds.
It has shake awake, a side removable battery, solar failsafe with auto brightness or manual brightness modes, 10 daylight and 2 nightvision settings, and is IP67 waterproof.
Read our full 507C ACSS review here.
4. Holosun 508T Green & Red Dot - Most Durable Open Emitter
Buy the 508T At The Best Price
Next on the list is the Holosun 508T. It's very similar to the 507C except it has a stronger housing made out of titanium and a square window that's a little bigger.
The 508T's square titanium housing is made to give it extra durability, both from the shape and the material.
It's available in Red or Green reticles and they come with Holosun's Multi Reticle System, which is a 32 MOA ring + 2 MOA dot, and can be toggled to show only the 32 MOA Ring or just the 2 MOA dot by holding down the "-" button for 3 seconds.
It has shake awake, a side removable battery, solar failsafe with auto brightness or manual brightness modes, 10 daylight and 2 nightvision settings, and is IP67 waterproof.
Read our full 508T review here.
5. Holosun 509T Green & Red Dot - Most Durable Closed Emitter
Buy the 509T At The Best Price
The 509T is going to be the most heavy duty pistol optic you can buy from Holosun. It's an enclosed emitter and made with a titanium housing. The titanium is not to make it lightweight, it's to make it more durable.
The 509T comes with and RMR adapter plate
The enclosed emitter ensures that nothing can obstruct the view of the emitter and the lens, meaning water, dirt, lint or any other molecule will not get inside the optic. It will also make the optic easier to wipe off if it were to drop in mud or something like that.
The 509T is not going to be the lightest optic, but it will be the toughest.
It also has a nice big FOV and is filled with nitrogen which will help with fog-mitigation, just like a scope.
It's available in Red or Green reticles and they come with Holosun's Multi Reticle System, which is a 32 MOA ring + 2 MOA dot, and can be toggled to show only the 32 MOA Ring or just the 2 MOA dot by holding down the "-" button for 3 seconds.
It has shake awake, a side removable battery, solar failsafe with auto brightness or manual brightness modes, 10 daylight and 2 nightvision settings, and is IP67 waterproof.
Read our full 509T review here.
6. Holosun 509 ACSS Vulcan Red - Best Specialty Closed Emitter
Buy the 509 ACSS Vulcan At The Best Price
Similar to the 509T is the 509 ACSS Vulcan. It is an enclosed emitter optic, but it has two major differences. It’s made out of aluminum and it has the ACSS Reticle (10MOA Chevron + 250 MOA Outer Ring)
- Enclosed Emitter
- Aluminum Housing
- Red ACSS Vulcan Reticle (learn more here)
- 10 MOA Chevron + 250 MOA Outer Ring
- Up to 50,000 Hours Battery Life (Setting 6 Dot Only)
- 12 Brightness Setting: 10 DL & 2 NV Compatible
- Side Battery Compartment
- Auto Brightness Mode or Manual Mode
- Solar Failsafe™
- Shake Awake™
- IP67 Waterproof
7. Holosun 507 Comp Green & Red Dot - Largest Window Competition Reticle
Buy the 507 Comp At The Best Price
Next on the list is the Holosun 507 Comp. This is one of the newest and most sought after optics from Holosun. Comp stands for "Competition" because this optic features a VERY large window, meant for competition shooting. It's the largest window in the industry.
The 507 Comp has some key differences vs the other optics listed here. First it has the C.R.S. which is the Complete Reticle System. This gives it many reticle configurations like a 2 MOA Dot only or a 2 MOA dot + 8 or 20 or 32 MOA Circle or just a 8 or 20 or 32 MOA Circle.
The 507 Comp also does not have a solar panel on it which means there is also no auto brightness setting.
It has a 7075 aluminum housing, shake awake, a side removable battery, manual brightness modes, 10 daylight and 2 nightvision settings, and is IP67 waterproof.
This is a large optic.
Read our full 507 Comp review here.
Best Arex Delta Gen 2 Holosun Optics (Type 5 Plate Modified RMSc Footprint) - Smaller Optics
Below are the best modified RMSc footprint Holosun red and green dot sights you can mount on your Arex Delta Gen 2. These all have a modified RSMc footprint so use the “Type 5” mounting plate that comes with the Arex Delta Gen 2.
1. Holosun EPS Red or Green 6MOA, 2MOA, MRS - Largest window with lowest deck height.
This is Holosun’s latest closed emitter optic and is made out of aluminum. It has a lower deck height than the 509T and 509. It comes with an RMR adapter plate but you won't need it since you can mount it directly to the Arex Delta Gen 2 Plate Type 5. This will give you the lowest deck height with largest window for this platform.
These EPS models come in red or green and either a 2MOA, 6MOA, or MRS Reticle. The MRS Reticle has a solar failsafe and auto brightness mode, the others do not.
- Aluminum Housing
- Enclosed Emitter
- Red or Green Reticles
- 2 MOA, 6 MOA, or MRS Versions Available
- RMR Adapter Plate Included
- Modified RMSc Footprint
- Auto Brightness Mode or Manual Mode (MRS Versions Only)
- Solar Failsafe™ (MRS Versions Only)
- 10 Brightness Setting: 8 DL & 4 NV Compatible
- Side Mounted Battery
- Shake Awake
- IPX8 Waterproof
Read our full EPS Full Size review here.
2. Holosun 407K Green & Red Dot - Best Budget Option
Buy the 407K At The Best Price
This is the most affordable micro optic Holosun makes and is available in a 6 MOA green or red dot.
If you are looking for a single dot optic that is very affordable and great for plinking then this might be the one for you.
The 6 MOA dot is a really nice size. It's big enough to pick up rather easily, but still small enough to be precise with.
It has an aluminum housing, side removable battery, manual brightness controls, shake awake, is IP67 waterproof, and 50,000hrs of battery life.
Read our full 407K review here.
3. Holosun 507K Green & Red Dot - Best All Around Option
Buy the 507K At The Best Price
The next step up from the 407K is the 507K. This has all the same features like an aluminum housing, side removable battery, manual brightness controls, shake awake, IP67 waterproof, and long battery life but it also has Holosun's Multi Reticle System (MRS).
The MRS Reticle is a 32 MOA Ring with a 2 MOA dot. It's really cool when you look at it - it's similar to an EOtech's reticle if you've ever seen them.
The other cool thing is you can toggle the reticle holding down the "-" for 3 seconds. So if you wanted to, you could use just the 32 MOA Ring, the 2 MOA Dot only, or both the 32 MOA Ring + the 2 MOA Dot.
Read our full 507K review here.
4. Holosun 507K ACSS Vulcan Green & Red Dot - Best Speciality Option
Buy the 507K ACSS Vulcan At The Best Price
Next on the list is the 507K ACSS Vulcan. This is exactly like the 507K except is has the ACSS Vulcan reticle. This reticle has a 230 MOA dotted outer ring and a 3 MOA center dot.
The purpose of this reticle is to help you find the center dot quickly if you are off center. To learn more about the ACSS Vulcan reticle check out our article here.
The dotted outer ring can be turned off by holding down the "-" button for 3 seconds.
The main advantage of the ACSS Vulcan reticle is to be able to find the center dot quickly when drawing the pistol.
All the features are the same as the 507K except for the reticle, and this is available in both red & green.
Read our full 507K ACSS review here.
5. Holosun EPS Carry - Closed Emitter Option - Best Enclosed Emitter Option
 Buy the EPS Carry At The Best Price
Available in 2 MOA Dot, 6 MOA Dot, and MRS, Red Dot or Green Dot. |
Features:
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The EPS Carry is very similar to the 407K and 507K except it has one major difference, it is an enclosed emitter optic. This means the laser emitter is protected by a hood. So dirt, mud, or debris will never get in the way of the emitter to distort the reticle.
There are 3 versions of the EPS Carry. The 2MOA, 6MOA, and MRS Versions
The MRS version has a solar panel on it which acts as a solar fail safe to power the reticle of the battery dies. It also gives you an extra auto brightness feature which can be toggled on or off.
Read our full EPS Carry review here.
Choosing between Red or Green Reticles
You may be wondering if you should get a red or green dot reticle. We get this question a lot so I am going to list a few bullet points for you to consider.
- Green reticles are less straining for the eye to see.
- Green reticles can help with astigmatism. If you have astigmatism you will see a blurry dot, we have been told by a few customers that Green dots help with their astigmatism, making the dot look more crisp than the red version.
- Green will not washout on backdrops like green grass, foliage, or green colors.
- In theory Green dots can have a longer battery life because Green is brighter, so for example a green dot on brightness setting 6 may be the same brightness as a red dot on setting 7 - which would save battery life.
If you want to learn more check out our full article about Red vs Green Dot Pros & Cons here.
Choosing between Open vs Closed Emitters
The simplest way we can break down open vs closed emitters is to look at how you plan on carrying the pistol. If you plan on being outdoors in the elements with rain, snow, sleet, then a closed emitter will be beneficial.
If you plan on carrying OWB most of the time and plan on being outside then closed emitter would be beneficial.
If you plan on carrying IWB or don't plan on being outside using your red dot in the pouring rain or heavy snow then an open reflex is fine.
Open reflexes will still work in the rain or snow but the closed emitter will give you extra peace of mind.
An open reflex can collect dust and debris on the inside of the reticle over time, so you'll want to clean it out from time to time. An enclosed emitter is easier to clean in this aspect.
To learn more about Open vs Closed emitters you can check out our Open vs Closed Emitter Guide here.
How to decide which reticle style is best for you
In this guide we covered a few different reticle options. If you need some help deciding which is best for you here are some of our thoughts on each.
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Conclusion
We really like the pistols Arex puts out and the Delta Gen 2 is no exception.
The engineers did a great job with this platform's optic mounting system. This allows you to put any Holosun Pistol optic you want on it.
There are many to choose from, all are great.
If you have any questions reach out to us on chat.
Thanks for reading!
