SVI Infinity - Dovetail Red Dot Mount, which Cut?

[IVC]

My main Limited gun is SVI in .40 I've had for some 5 or 6 years. Luckily, at the time I ordered it with an extra 9mm fitted barrel and conversion (breech face, extractor, springs). Now that we have "Limited Optics" division and it's minor only, I'm thinking about doing the conversion to 9mm (or even shooting .40 minor) and adding the red dot. I don't want to cut the slide (yet) because I want to keep the change "reversible." At least at this time.

 

What is the rear sight cut on an SVI and how can I tell or measure it to be sure? SVI website talks about "low base/Infinity" and "high base/Bomar" cuts when ordering replacement iron sights. Any recommendations for mounting plates that would work with the existing dovetail? 

[konkapot]

EGW makes the plates for the purpose; maybe ping them directly? I bet they'd know. 

 

Also look at the rear sight itself; it might/hopefully say "Bo Mar" on it. That would narrow it down. 

[ltdmstr]

Here are the dimensions for the BoMar cut if you want to check it.

[IVC]

Thanks guys, the verdict is in - I talked to EGW, they asked for photos and some measurements and it looks like it's a Bomar cut but it's too deep in the slide for their mount to fit. 

 

The problem is the "step" from the shelf where the sight sits and the top of the slide. For some reason it's not marked in the diagram above (thanks @ltdmstr). The "step" is in the second image just to the left of the number ".100". Mine measures .150, while EGW has it at .120 on their mounts. If I tried their Bomar cut mount, the front of the mount would be hitting the slide, lacking .030 of clearance. 

 

Thinking back, this is likely (probably/maybe/who knows) the difference in the SVI rear sights when they talk about "Bomar" vs. "Infinity/low base." My guess is that the "base" is the shelf on which the sight sits and it's (at least) .030 lower than standard. Although I can't tell what the standard depth is from the diagram above.  

[Arakisk]

I had been wondering about this exact same possibility. It's a shame that EGW mounts don't work, but I'm not surprised since Infinity does make their guns extremely purpose-built (especially looking at their slide ride guns).

[pjb45]

I have two EGW Bomar plates for my Infinity guns.

 

[IVC]

An update about the final result, for those who have the same issue.

 

I contacted everyone and their uncle trying to get someone, anyone, who would be able to do a plate. I couldn't even get a response. Then I threw in the possibility of cutting the slide and making the change permanent, with about the same level of futility in the exercise. Finally, one guy responded after many weeks (won't drop names), about how he missed my e-mail, but then I had hard time keeping the basic communication going, waiting weeks to get a response to the basic questions. To say it was frustrating is an understatement. I sort of gave up for the time being, but then decided I was going to find a way even if it killed me. 

 

Turns out that just airing my grievances with the local shooters was the ticket. At a low level local match I was shooting my Open SVI and the chat inevitably turned to the gun and the rest of the gear. As I complained (whined) about not being able to set up a Limited Open gun and having to waste "my precious" 38SC brass, one shooter on my squad highly recommended a local shop in San Diego that does all sorts of awesome mounts. I  contacted the guy and the rest is history - he responded quickly, I called him, sent him the slide one Friday, he received it on Monday and, to my utter surprise, he sent me the photos of the mounted optics the same day. I'm pretty sure he did it to impress me, and impress me he did. More than impressed me. A few days later, I had my slide and could finalize the (now permanent) conversion from .40 Limited to 9mm Limited Optics. With the slide cut, there's no going back to irons. 

 

Turns out it's a system with cutting the slide and a type of custom plate, it's all on the website at: https://twosee.us/. (I am not affiliated in any way and this is just giving the guy the credit he earned). I'll post a few photos of the slide, the gun and the results of sighting in. 

 

[IVC]

Here's what the slide looks like. These are the photos he sent me initially, it's still at his shop at this time.  

 

 

 

[IVC]

And here's what the gun looks like, together with the final target for sighting in. It's at 25 yards, off the sandbag (don't own a rest, unfortunately). The inability to center the dot with precision at that distance is causing part of the spread. The load was a basic 147 Blue  Bullets over 3.2 grains of N320 at 1.145, which was an older load I had lying around. 

 

 

The flier at the bottom was before the final adjustment, so it doesn't count. There are five hits in the group, showing around 5 MOA (1.2" at 25 yards). My *guess* is that the gun is about 3 MOA at this distance with this ammo, and that if I shot it from the rest and with precision bullets it would blow my mind away. Either way, it's ready for the prime time.

 

(Ignore the dirt and the scratches, it's a tool and a fine tool at that.) 

[NorthwestGuy]

Great to find craftsmen who can make it happen.

Thanks for the information.

[sandflea316]

Good stuff man.  Might go that route as well.  Thanks for all the leg work

[sandflea316]

Sent him my SV slide last week.

He just contacted me with the finish work and shipping out tomorrow 

Two week turnaround.

Interesting enough they have a rear sight that mounts on top of SRO or 507 for those that want BUIS

[IVC]

The extra rear sight requires tinkering with the front sight to get the elevation correctly. Wasn't worth it for me, I dedicated this gun to optics. Post photos of how it ended up and whether there are any issues. 

[sandflea316]

Here's my SV.  Originally was a 9mm iron sight gun for 3 gun.

Last year I sent it off to be converted to an open gun.  Had the slide milled for a racker.  So that's why there is a gap

[2MoreChains]

Following.  I was just on TwoSee’s website.  Anybody have any experience with their 2C 1911 Direct Mill cut for the SRO on a 1911/2011 slide that does not require a mounting plate?  Cuts the optic pocket low enough that they had to do a step cut on the top of the slide to clear the SRO’s hood.  

 

https://www.instagram.com/p/CodOaAOS6GG/