The Docter footprint

The tables on this page own the full Docter optic list and the plate systems that present it. The sections below carry what a table cannot: how to identify the pocket when the usual screw count test fails, exactly what geometry this dataset does and does not publish, the several names the pattern is sold under, and where Docter sits relative to the patterns it competes with on the same slide. The side by side argument against the RMR lives in Docter footprint vs RMR, which this page links rather than repeats.

How to identify a Docter pocket when the socket count ties

Most footprint guides tell you to turn the optic over and count the screw holes and the recoil sockets. On this pattern that advice runs out, and it is worth knowing exactly where it runs out before you buy a plate.

Four of the nine footprints on this site publish the identical signature. Docter records a screw through mounting style, 2 screws and 4 recoil sockets. So do RMSc, DeltaPoint Pro and the full size Holosun EPS. Counting gets you to a four way tie, and the four are not interchangeable with one another in either direction. The cost of guessing wrong is the whole spread of the catalogue:

• RMSc, 30 optic pages, reached by 186 of the 196 pistols
• DeltaPoint Pro, 15 optic pages, reached by 112 pistols
• Docter, 6 optic pages, reached by 55 pistols
• Holosun EPS, 1 optic page, reached by no pistol here

What the socket count does settle is the comparison people actually make, which is against the RMR: RMR records 2 recoil lugs where this pattern records 4, and two is not four. That single test separates Docter from the 33 optic pattern next to it and from Holosun K, which also records 2. It separates it from nothing else.

So identify by label and by model, in that order. Three checks that do work:

1. Read the plate listing, not the kit box. Because no slide here is milled for this pattern, your pistol never tells you whether Docter is available. The plate does, and plates arrive marked. OuterImpact’s modular adapter listings name the pattern directly and list the optics it accepts (outerimpact.com).
2. Match a part number, where one exists. Four of the 6 optic pages here carry a real manufacturer part number: the Burris FastFire 3 at 300234, the FastFire 4 at 300259, the Primary Arms SLx RS-10 at 810024 and the Crimson Trace CTS-1250 at 01-00560. The two Vortex rows carry only the model name, so there is no number to match for a Venom or a Viper.
3. Use the optic to identify the pocket, not the pocket to identify the optic. The pattern has six members and they are all named on their own product pages. Working backwards from a known optic is reliable in a way that measuring a pocket with a ruler is not.

Pattern and dimensions, and the numbers this page does not publish

Here is the complete set of geometry this dataset holds for the pattern, and the source for it. Docter mounts screw through, with 2 screws passing down through the optic body, and 4 recoil sockets in the underside of that body which drop onto pins standing up from the plate. OpticsPlanet’s footprint guide is the source recorded for the socket arrangement, describing a pattern that utilizes 2 screw holes and 4 sockets to accept recoil pins (opticsplanet.com), and Optics Trade’s survey covers the same family under both the Docter and Noblex names (optics-trade.eu).

Everything else is not published here, and the gap is deliberate rather than an oversight. No screw spacing, no socket diameter, no thread pitch and no body length appears on this page, because neither recorded source carries a drawing and no first party Docter or Noblex document is recorded against the pattern. The same shortfall runs through the optic rows: of the 100 optic pages on this site, 0 publish a window width, a window height, a weight or a battery type, and that is true of all 6 Docter pages too. What the Docter rows do carry is 4 reticle specifications and 4 UPCs out of 6.

Stating a screw spacing we cannot cite would make this page more useful looking and less true, so the dimension that would settle a borderline case is the one dimension nobody here can give you. Until a manufacturer drawing is recorded, the part number is the measurement.

The names this pattern is sold under

This is the pattern’s real difficulty, and it is a labelling problem rather than an engineering one. The interface is sold under at least three of its own names and several borrowed ones, and the plate you need may carry any of them.

Its own names. Docter is the name this site uses. Noblex is the same pattern under its other current name, which is why this dataset records the family as Docter / Noblex. Doctersight is the historical name, recorded in this pattern’s own description.

Borrowed names, which is where the money gets lost. Plate makers routinely label the pocket with the name of an optic that fits it. Taurus’s own TORO plate kit page sells one plate as fitting “Vortex Venom/ Doctor Noblex / Burris Fast Fire/ Sightmark Mini” (shoptaurus.com), four labels for one interface, with the pattern’s name misspelled in the middle of them. EGW sells its mount as fitting “Burris FastFire and Docter” (egwguns.com). Shadow Systems’ own mounting instructions for the MR920 go further and drop the pattern name entirely, listing the Vortex Viper as a standard of its own beside the Trijicon RMR and the Leupold DeltaPoint Pro (shadowsystemscorp.com).

The practical rule: treat any of Docter, Noblex, Doctersight, Vortex Venom, Vortex Viper or Burris FastFire on a plate listing as naming this pattern, and confirm against the specific optic you own. One caution on that list. The Vortex Venom name is ambiguous by itself, because the enclosed Venom is a different pattern, and the Sightmark Mini named on the Taurus listing has no page in this dataset at all, so it is a label we can report but not corroborate.

Look-alikes that will not interchange

Beyond the four way signature tie above, three more comparisons come up often enough to be worth settling.

• RMR, the one the pattern is usually confused with. Two recoil lugs against four sockets, and 33 optic pages against 6. Every Docter capable pistol here is also RMR capable, which is the subject of the linked article.
• C-More STS, the pattern below this one. It records 2 screws and 0 recoil lugs, so it is the one member of the screw through group a socket count genuinely separates. It holds 1 optic page and is reached by 28 pistols, every one of which also reaches Docter.
• ACRO, which is not a comparison at all. ACRO clamps sideways onto a dovetail rather than screwing down, records 1 screw and 1 recoil stopper, and holds 5 optic pages reached by 80 pistols. If the optic in your hand has no holes through its base, you are not looking at this pattern.

Nothing on this list is a plate system. Glock MOS, SIG P320 X-series and the rest are factory plate systems, not footprints: they present a footprint through a plate, and the plate you fit decides which optics mount.

Where Docter sits in the mounting ladder

The plate table on this page lists the 10 systems that present the pattern. What the table cannot show is how those paths relate to the other patterns on the same slides, and that relationship is unusually clean here. Computed across all 196 pistols, the reachable sets nest exactly:

C-More STS, 28 pistols, sits inside Docter, 55, which sits inside DeltaPoint Pro, 112, which sits inside RMR, 117. Not approximately: every pistol in each set is in the next one, with no exceptions in either direction. ACRO’s 80 pistols nest inside DeltaPoint Pro and RMR as well, off to the side of the middle rungs.

Three consequences follow, and they are the whole decision.

Docter is never the only way to get a dot on a gun. Whatever slide you are holding, if a Docter plate exists for it then an RMR plate and a DeltaPoint Pro plate exist for it too, with 33 and 15 optic pages behind them against this pattern’s 6.

No optic brand is locked behind this pattern. Four of the nine footprints here do lock one: Trijicon sells only on RMR, Shield Sights only on RMSc, Aimpoint only on ACRO, EOTech and Leupold only on DeltaPoint Pro. Docter locks none. All four of its brands, Burris, Vortex, Primary Arms and Crimson Trace, sell on at least one other pattern as well, so a Docter plate buys you six specific models and never a brand you could not otherwise reach.

The one place the arithmetic shifts is the Taurus TORO. Its kit is the only Docter carrying system here with no RMSc plate recorded, which is why its 4 pistols reach 55 optics where a Beretta 92XI reaches 89 and a Walther PDP Gen 2 reaches 90. On a list that short, six optics is a real branch rather than a rounding error. The linked article works that case through in detail.

What a Docter plate is actually worth

Because the optic lists of the patterns in a plate kit do not overlap, the value of adding this plate is exactly countable: 6 optic pages, no more and no less. There is no hidden overlap to discover and no second pattern that comes along with it.

That makes the buying rule short. Buy the plate when the optic came first: you own a FastFire 3, an older open emitter Venom or a Viper, the sight is a real object in a drawer, and one plate puts it on the gun. Check that your pistol is one of the 55 and that its kit sells this plate separately, and you are done.

Do not buy the pattern in the abstract. If you are choosing glass with the pistol already decided, the same slide reaches 33 RMR pages and 15 DeltaPoint Pro pages, both supersets of this one’s reach, so choosing Docter costs you options and buys you nothing structural. No price guidance appears on this page: offers shown next to the optic rows come from retailer feeds and move without notice, and a street price quoted in editorial copy would be wrong within the month.

The enclosed emitter rule

One property of this pattern decides a whole category of purchase, and it is absolute in this dataset. All 6 Docter optic pages are open emitter sights. Zero are enclosed. Docter is the only footprint here with more than one optic page and no enclosed member, against 27 enclosed pages across the 100.

The patterns at the other extreme are worth naming, because they are what people move to: ACRO is 5 of 5 enclosed, the Holosun EPS 1 of 1, the Holosun 509T 2 of 2. The mixed patterns carry the volume, with RMSc at 8 enclosed of 30 pages and DeltaPoint Pro at 5 of 15.

The useful part is that the nesting above makes this a plate decision rather than a pistol decision. Every one of the 55 Docter capable pistols reaches enclosed options through a different plate in the same kit. The leanest case is the TORO at 8 enclosed pages; a Beretta, a Walther PDP or a Springfield Echelon reaches 21. If sealing the emitter against lint and rain is the requirement, nothing on this page will do it, and the fix is one plate away.

How well sourced this pattern is

Worth stating plainly, because it runs against what a six optic list looks like from the outside. This is the best verified pattern on the site among those with more than two optic pages: 5 of its 6 optic pages carry the verified flag, against 48 of the 100 optic pages site wide. For comparison, RMSc verifies 19 of 30, RMR 14 of 33, DeltaPoint Pro 5 of 15, ACRO 2 of 5, and Holosun K none of its 5. A verified row means a manufacturer page naming the pattern for that exact model, or two independent sources doing so, recorded against the row.

Two caveats, both on the page because they bear on what you can trust here.

The one unverified row is the Burris FastFire 3: its sibling the FastFire 4 states the pattern on Burris’s own page (burrisoptics.com), while the FastFire 3 page does not name it the same way (burrisoptics.com), so the row rests on a third party compatibility article. It is very probably right and it is not proven here.

The pattern record itself is the weaker half. It rests on two third party footprint round ups and nothing from Docter or Noblex, which is why the dimensions section above has so little in it, and the two Walther plate paths rest on a single third party plate guide. The Primary Arms SLx RS-10 page states that an adapter plate for Glock MOS ships in the box, while this dataset records no Docter plate on the Glock MOS system; that contradiction is unresolved and is the reason the reach figure here may understate the truth by 16 pistols. This site will not claim a fit nobody published.

Where to go next

The full footprint index lists all 24 interfaces, 9 patterns and 15 plate systems, with their optic and pistol counts side by side. Docter footprint vs RMR argues the subset relationship in detail and works through every plate system’s share. If you have landed here holding an optic rather than a pistol, the Vortex Venom page lists all 55 pistols that one sight fits. If you are not yet sure your pistol needs a plate at all, do you need an adapter plate answers that first.