P320 XFULL - What Holosun to buy?

You will need a spacer or adapter depending on what mounting holes your have. I use the C&H spacers which come with the appropriate screws for your application.

507K is a smaller slimline optic. It will not fit without an adapter, it is not a RMR pattern.

507C is the RMR footprint. Fit will depend on if your slide is threaded for the RMR. You have to take your cover off to what your slide has. If you do have the RMR holes, you dont “need” a plate, since the RMR footprint is smaller than the DPP/Romeo 1 Pro (assuming thats what your slide is cut for). But you will have a gap since its smaller. It’ll probably be tough to find the 6-40 screws locally thats Sig taps the RMR holes for, because everything uses the 6-32 thread pitch.

Out of those 2 definitely get the C. I ended up just going with a romeo 1 pro so I didn't have to use a plate. No regrets its a good optic. I bought an FDE one first but decided to go back to all black so now I have to choose to sell the optic or buy another gun...

Thanks to everyone for the replies.

Would I be better off just buying a Romeo 1 Pro?

In the same position looking for an optic for my new x-full. This will be my first RDS pistol. Pretty sure I am going with the 507c but still trying to decide between red and green. Anyone try the 508?

C.I.Sig said:

In the same position looking for an optic for my new x-full. This will be my first RDS pistol. Pretty sure I am going with the 507c but still trying to decide between red and green. Anyone try the 508?

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Ive got a 508t. Its not mounted on anything yet but its going on one of my CZs after it gets milled. its nice but the window definitely seems smaller than the R1 pro. I have both and can take some photos of you want.

Dr. Zombie said:

Thanks to everyone for the replies.

Would I be better off just buying a Romeo 1 Pro?

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I have 2 romeo 1 pros. 1 holosun 407k, one holosun 508t, 1 SRO, and one Romeo 3 max. they all have pros and cons but for your purpose id just snatch up a used Romeo 1 pro and not have to worry about plates. Thats exactly what I did on my sig. I think its a good optic especially considering you can get one used between 250-280 and not have to spend more on plates.

Thechef1 said:

I have 2 romeo 1 pros. 1 holosun 407k, one holosun 508t, 1 SRO, and one Romeo 3 max. they all have pros and cons but for your purpose id just snatch up a used Romeo 1 pro and not have to worry about plates. Thats exactly what I did on my sig. I think its a good optic especially considering you can get one used between 250-280 and not have to spend more on plates.

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That's kind of what I was thinking. I can't see spending $70 on a plate if I'd be OK with the Romeo 1 Pro.

507C is a good size for a fullsize gun. I run a C on my vtac.

Dr. Zombie said:

That's kind of what I was thinking. I can't see spending $70 on a plate if I'd be OK with the Romeo 1 Pro.

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Yeah that was my thought exactly R1 pro is a good dot. Sig has some questionable ones but the R1pro and R3 max are nice.

I personally like the holosun’s. The C&H spacer plates used for the holosuns are pretty good, one thing to point out is the mechanical interface between the optic, plate and the slide. They diff lock and screw together to make it a much stronger set up. I have been looking at the new holosun eps and eps carry. They use the K footprint which is the same screw holes as Romeo pro / delta point pro. Put the eps together with the C&H spacer plate for the K footprint and I think that’s going to be a excellent set up.

Hammer said:

The R1P and the 407/507K are both solid - just depends on what features you want. While I have a R1P on my P229 and have been happy with it, I went with the 407K on my X-Full:

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That’s a 407C.

The 407/507K’s have a flat hood without those 2 grooved lines.

ZEEOH6 said:

That’s a 407C.

The 407/507K’s have a flat hood without those 2 grooved lines.

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Yes, thank you. I mis-typed above - it's the 407C, not the 407K. I still get them mixed up for some reason.

* Corrected above to avoid any further confusion.

507C is a great option. The ACSS Vulcan versions are great if you are new to Optics as it is one of the easiest to acquire when presenting IMO.
Red Dot Version
Green Dot Version
Good Video Explaining how it works from Aaron at Sage Dynamics

Good luck!

Thanks for the tip on the ACSS reticle. I had not seen that before. This is my RDS pistol and this may be the route for me to go. Will do more research.

Thechef1 said:

Ive got a 508t. Its not mounted on anything yet but its going on one of my CZs after it gets milled. its nice but the window definitely seems smaller than the R1 pro. I have both and can take some photos of you want.

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Would love to see some pictures and hear your thoughts on build quality. Worth the extra cost over the 507?

If it’s a carry piece then it’s a 508T all the way. I’m running a 508t on my carry build. A 507c x2 ACSS on my comp build and planning on the new holosun eps carry for my next build.

The NEW soon to be release HOLOSUN EPS, EPS Carry 6moa/G/R or Multi-Reticle Green or RED. Is pretty NICE!