Hey Freedom Gorillas, today we are going to explain the similarities and differences between the Holosun 509T X2 and the 508T X2. These are two of Holosun's toughest optics - made out of Grade 5 Titanium. We understand that it can be difficult to understand the differences when you don’t have them both in your hands.
So first thing to know is that the 508T X2 is an RMR footprint and the 509T X2 comes with an RMR footprint adapter plate. This means that in order to mount either of these optics your gun needs to have an RMR footprint or some kind of adapter plate to mount the 509T X2. You can check out our fitment guides here and they will explain which Holosun optics fit your pistol and any type of adapter plate you may need.
TLDR: The main difference between the 508T X2 and the 509T X2 is that the 509T X2 is an enclosed emitter and uses a clamping mechanism design, while the 508T X2 is an open emitter and has an RMR footprint. You can learn more about open vs closed emitters here.
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- Holosun 509T X2 vs 508T X2 Models & Pricing
- Holosun 509T X2 vs 508T X2 Footprint
- Holosun 509T X2 vs 508T X2 Size & Intended Use
- Holosun 509T X2 vs 508T X2 Deck Height
- Holosun 509T X2 vs 508T X2 Reticles
- Holosun 509T X2 vs 508T X2 Battery Life
- Holosun 509T X2 vs 508T X2 Similarities
- Holosun 509T X2 vs 508T X2 Differences
- Holosun 509T X2 vs 508T X2 Which is Better?
- Holosun 509T X2 vs 508T X2 Conclusion
Holosun 509T X2 vs 508T X2 Models & Pricing
The 509T X2 is about $60 more than the 508T X2. These are both on the higher priced side because they are made out of Grade 5 Titanium to make them ultra durable. They are some of the most durable pistol optics on the market.
The 508T X2 and the 509T X2 come in red and green reticles. The 509T X2 also comes in FDE color in both red or green.
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Starts at $429.99 
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Starts at $369.99 
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Holosun 509T X2 vs 508T X2 Footprint
The 508T X2 has an RMR footprint. The 509T X2 has a different style of mounting. It uses a clamp + plate system. The 509T X2 ships with an RMR adapter plate.
The 509T X2 also has many aftermarket adapter plates on the market. You can see some of them on our 509T X2 Adapter Plate section here.
A 509T X2 Adapter plate comes in handy for pistols that use a multiple plate system like the Glock MOS. If you wanted to put a 509T X2 on your Glock MOS, you could use the included RMR plate from Glock, and the RMR adapter plate with the 509T but then you will have two plates on top of each other, and extra deck height.
If you were to use an adapter plate like this Calculated Kinetics 509T X2 Glock MOS Adapter Plate then you would eliminate the original Glock MOS RMR plate, and use just one plate to mount the 509T X2. This would give you a lower deck height, and less plate stacking.
Holosun 509T X2 vs 508T X2 Size & Intended Use
The 509T X2 and the 508 X2 are somewhat similar in size. The 509T X2 has more weight to it due to the adapter plate and the enclosed emitter.
The window sizes on both are very similar but the 509T X2 has a little more viewability.
Both of these optics are meant for use on full size or compact pistols. They aren't intended for use on subcompact or micro compact or slim pistols, and most likely won't fit anyway due to their RMR footprints.
Holosun 509T X2 vs 508T X2 Deck Height
The deck height on the 509T X2 and the 508T X2 are different. The 508T X2 has a deck height of about 8.5MM while the 509T X2 has a deck height of around 10MM without the adapter plate. The 509T X2 Deck height with the adapter plate is likely around 12-13mm.
You have a greater chance of co-witnessing with the 508T X2 than you do with the 509T X2.
Holosun 509T X2 vs 508T X2 Reticles
Both the 509T X2 and the 508T X2 come in red or green reticles and have the MRS reticle system. Which is a 32 MOA outer ring and a 2 MOA center dot.
The outer ring can be turned off by holding down the "-" button for 3 seconds. You can use the 32 MOA outer ring only, the 2 MOA Dot only, or both together.
Holosun 509T X2 vs 508T X2 Battery Life
Both the 509T X2 and the 508T X2 have the same battery life. They are both rated at 20,000hrs of battery life on setting 6 using the MRS reticle, and 50,000 hours of battery life on setting 6 using the 2 MOA dot only.
Holosun 509T X2 vs 508T X2 Similarities
- They both come in red or green reticles
- They are both made out of Grade 5 Titanium.
- They both have solar failsafes, auto brightness, and manual brightness modes
- They both have side removable batteries
- They are both IP67 waterproof
- They both have shake awake
- They both have the Multi Reticle System (MRS)
- They both have 20K hours of battery life when using the MRS reticle and 50K hours of battery life when using the 2 MOA dot only
Holosun 509T X2 vs 508T X2 Differences
- The 509T X2 is an enclosed emitter optic and the 508T X2 is an open emitter optic.
- The 509T X2 uses a clamp + adapter plate style of mount and has many adapter plates you can purchase for different firearms. It comes by default with an RMR adapter plate.
- The 509T X2 has a higher deck height than the 508T X2, which means it will sit higher and block more of your iron sights than the 508T X2.
- The 509T X2 is more expensive than the 508T X2
Holosun 509T X2 vs 508T X2 Which is Better?
As you can see the 509T X2 has quite a few differences compared to the 508T X2. So how should you decide which one to get?
Well we think you should figure out first and foremost if you want an open or closed emitter optic. You can read more about that in our open vs closed emitter guide here, but that is going to be the biggest difference.
The second thing to ask yourself is if you need the titanium housing. To us, titanium is great if you need a duty optic. Most of the other Holosun Optics are 7075 T6 aluminum which is plenty strong, however if this is going to be used and abused then the titanium can withstand drops, bangs, and impact better than the aluminum.
The 509T X2 is about $60 more than the 508T X2. Also if you are looking for a closed emitter but don’t need it to be titanium then you can check out the Holosun EPS series, it’s very similar to the 509T X2 but is made out of aluminum.
The third thing to consider is the deck height. If you don’t mind having an open emitter, the deck height on the 508T X2 is lower than the 509T X2. This means you’ll have a better chance of seeing your iron sights through the optic when mounting. This is all dependent on your specific pistol and optic cut and sight height.
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Starts at $429.99 
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Starts at $369.99 
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Conclusion
The 508T X2 and the 509T X2 are both awesome optics. There’s no doubt having a titanium optic on your pistol will give extra peace of mind and confidence. If you are a police officer, security, military member, or someone who needs a duty optic then these are the two I would look at.
If you are really serious about co-witnessing, both can be adapted to co-witness if you put in enough time and effort and research. You would need to make sure you have the right iron sights, slide cuts, or adapter plates.
We hope you found this guide helpful and if you have any other questions please reach out to us.
Thanks for reading!
