School me on locking ARCA rails

mj23polaris

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Dec 28, 2019
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So I'm wanting to put a ARCA rail on AR10. Is Area 419 and Seekins the only people who make a M-lok specific rail that has "notches" to lock the clamp from moving horizontally?

Are their clamps proprietary to their rails?

Will this work with all of them?

Anyone have any input on direction to go, I'm leaning Seekins for the rail length and how it lines up with my handguard but their clamp as far as I can tell requires you to put a pic rail on it to them attach a bipod bc the clamp is slotted mlok. Wich seems kinda dumb to have to get a ARCA rail, get their clamp, get a pic rail, get a 1913 to 17-s and the a bipod.
 
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You don't need any teeth or notches on your ARCA rail, in fact, I believe most (including me) prefer them without it. Any good clamps made by legit manufacturers like RRS, etc will hold tight to a normal ARCA rail.

IMO, don't worry about the rail, but if the clamps are available in a version that will attach to both ARCA and Picatinny, those are the most useful since then you can use the bipod (or whatever you're trying to attach) on anything.
 
So I'm wanting to put a ARCA rail on AR10. Is Area 419 and Seekins the only people who make a M-lok specific rail that has "notches" to lock the clamp from moving horizontally?

Are their clamps proprietary to their rails?

Will this work with all of them?

Anyone have any input on direction to go, I'm leaning Seekins for the rail length and how it lines up with my handguard but their clamp as far as I can tell requires you to put a pic rail on it to them attach a bipod bc the clamp is slotted mlok. Wich seems kinda dumb to have to get a ARCA rail, get their clamp, get a pic rail, get a 1913 to 17-s and the a bipod.
The RRS USR rails are made to go with that SC-ARC clamp. They have locking holes that will connect with that pin if there is movement when the clamp is tight. There are different sizes and options for M-Lok.

Cool thing with that clamp and those rails, if you tune the clamping pressure half way, you can change the positioning forward and batch just by utilizing that thumb switch.
 
Fgradepompousavage Something tells me you don't know as much as you think you do.

Was it invented by a camera type company? Yes. Was it copied widely? Yes. Was it copied well? No. Read the history of what you don't know.

"

THE REALLY RIGHT STUFF​

1.5" DOVETAIL STANDARD​

BACKGROUND​

Prior to RRS, camera plates with dovetail rails were by and large extruded from dies, cut to various lengths, then either slotted and/ or tapped. The process was inherently imprecise compared to CNC machining operations. More companies started making plates using the same process by getting their dovetail specs "close enough" to work with any screw-knob style clamp already on the market. This is probably why screw-knob clamps seemed to be the only option for years and why most companies still push them today.
RRS plates are CNC machined, and have been from the very beginning. In 1990, Bryan Geyer made a good faith effort for better compatibility by adopting the Arca-Swiss plate style and dimensions. At the time, Arca-Swiss was one of the most popular photography ball head and plate manufacturers, so the term "Arca" was widely used to describe the style of plate that had a dovetail running on each side. A basic way to describe the "Arca" style would be that "Arca" can mean any dovetail rail that appears similar; however, the critical dimensions can be significantly imprecise.
Over time, our customers were getting more and more frustrated that several non-RRS plates did no work well with our patented and popular lever-release (LR) clamps.
We analyzed a collection of plates from various manufacturers and found many inconsistencies, as there was no industry standard for a dovetail rail. We reached out to those companies and began to work with whomever was willing to cooperate to adopt a common dovetail standard. In conjunction, we standardized our dovetail drawings so that any manufacturer could understand them.

BENEFITS OF THE STANDARD​

A customer will know the products they are considering will be compatible with RRS gear if the manufacturer indicates their products adhere to the "RRS Dovetail Standard" on their website, product manuals, or on the product themselves. Conforming to this standard helps other manufacturers ensure compatibility across the industry, with an additional benefit being fewer customers returning products for incompatibility issues.
Recently, we had a precision gauge made for our RRS standard. This is available for compaines who what to use our standard and to machine their own rails confidently. We have it available to them at cost.
If a 3rd party dovetail is manufactured over spec and is used with a non-ARC SOAR clamp, most of the time it will not shut. The new ARC clamps allow for adjustable tension, increasing compatibility across these rails.
If excess force is used, it could break the clamp. If the customer is using original LR clamps, the springs can become deformed resulting in the clamp sliding over time. If the plate is under spec it will slide freely.
Our clamps are a friction locking system meant to help get in and out of position quickly, while efficiently changing positions, so there could be some movement depending on a variety of external forces. Knowing that, we incorporated small threaded sockets where you can install safety stops on all RRS plates.

Currently, we publish the RRS Dovetail Standard as an open and free standard.​

best

"

Guess what that means. Most rifle arca's work together better than most camera arca's out there. Lots of reputable rifle oriented companies are on the rrs arca standard.
Pretty sure all of the brands mentioned above all go off that drawing.
 
@mj23polaris So you have an mlok handguard or are thinking of getting one. You are thinking of getting an ARCA rail of some flavor. Likely locking.

All of the brands you mention are working from the same basic 1.5" dovetail arca blueprint. The 3 I know of add the lock differently. Area 419 has arcalock, rrs has their rrs-lock, and the seekins has their mras rail. Not really interchangeable for locking. The clamps on the other rails will still work but not lock. Most of the time you don't need the locking style especially if you buy quality. If you get the rail with the notches it will work with the non notch clamps as well. It is backwards compatible.

The clamp you chose is great and probably the best. It's benefit is that it will connect to 3 rails. The rrs-lock, standard rrs standard arca (quite widely adopted in gun world and the underlying dove tail across all 3), or picatinny all in one clamp. Lever has 3 positions. Open for attaching. Middle for sliding on arca. Open and middle will fall off pic rail. Closed locks it down for both arca and pic.

The seekins mrac clamp makes no sense to me. Area 419 has a knob clamp. To work on standard arca requires removal of their locking capability.

Mine is the older version (non locking) SC-arc clamp. One screw on top. The new version is 17s compatible and no modification to work with locking or non locking.
20230427_235227.jpg


On my mlok strike rail on a piece of pic rail. Don't have arca on it cause I wanted the mlok vertical grip. Will put a short piece on it later when I finally get around to getting a tripod.
20230427_235123.jpg


On my MDT t1x mlok bottom chassis with magpul made arca rail.
20230427_235155.jpg


Same bipod also moves to my krg whiskey 3 t3x on its krg arca rail.

None of my arca rails have the notches. Haven't used it enough to notice any sliding. More companies make standard arca rails. Magpul, krg, and a few others make mlok attachable rails. Only benefit I see to go seekins is if you need to attach an mlok accessory on top of the arca rail. Downsides to the seekins and 419 rail are sides are more saw tooth/ cheese gratery.

Don't really see any vertical grips that attach to arca. Closest is a hand stop. Or you could have a short piece of rail at the back, open mlok for a vertical fore grip, and a piece of pic or arca at the front for a bipod.

Good luck with trying to make a decision.