Ambi mag release and other parts.

[CoryCop25]

Roger, have you experienced any unintentional mag releases from the EMR laying on armor/kit?

[Duffy]

EMR (through hole, TDP height) is no more likely to cause unintended mag drops than a factory button, I haven't heard of EMRs do it, but have heard it happened with factory buttons, so I imagine it can with the EMR (which is our reason for making the 10.9lb mag catch spring). When it has only 6 or 5 turns, it'll stick out of the mag release fence, at which point, constitutes an accidental / intended mag drop risk. It takes 8 turns of the mag catch till the tip of the shaft is even with the top of the top of button. I've seen a void in the mag button's hole, and I'm not sure why the shop or user installed the mag catch or button like that, a void in the top surface isn't as comfortable. When it's flush with the mag release button, the finger can't notice there's a hole there. Maybe they don't know, or think a button that sticks out further is easier to use (it can be to some), but it has consequences.

A properly installed EMR:

[26 Inf]

I received the two EMR-A's I ordered a couple days ago. I had Grand-kid duty Friday and didn't get around to installing them until late in the evening, so no shooting with them as of yet.

I like them, a lot. I installed one on my SBR replacing the Norgon clone that I had installed on the rifle. At first I was not going to use the extra spring rate mag spring. I compared the springs by compressing them in my hand, the enhanced spring felt a lot stiffer, about 60% stiffer I'd guess. I figured the mag release would be too stiff for my liking with the enhanced spring installed. Then I figured WTF, I can take it out if it don't like it.

Surprisingly, when installed there wasn't appreciably more effort required than with the normal spring. Seated and tugged a loaded mag a couple times in the garage and pronounced it good to go until I could get to the range and shoot.

At this point I have had the Troy, Norgon (clone), and KAC ambi releases installed on rifles with the KAC being my favorite. The KAC lever is longer than the FCD EMR-A lever. However, for me this is not an issue, I easily and naturally reach both of them. The EMR-A is far less likely to be rendered inoperable by something snagging on it than the KAC.

This moves it up on chart for me in terms of like. Subjectively, to me both the KAC and EMR-A require about the same amount of effort.

The only downside: I have also experimented with a couple different style bolt catch/releases. I was looking for one that moved the release pad further to the rear of the rifle for lefty use. At this point the ones I have used are the Seekins Enhanced Bolt Catch and the Geissele Maritime Bolt Catch. On my rifles, the EMR-A will not work with the Geissele Maritime Bolt Catch.

[Duffy]

I'm glad you like it The 60% extra power spring doesn't feel 60% stiffer when installed.

As ou noted, the EMR-A is incompatible with Bill's Maritime bolt catch. We have our own (ABC/R, and we're on version 2 now). The ABC/R was designed specifically for use with ambi mag releases that obscure/mask the bolt catch's lower paddle. It was suggested that its lower paddle be more biased towards the rear, but we didn't (and still don't) see much need for it, so ANC/R's lower paddle has 3 times the surface area as a standard bolt catch, and all of it optimized for use with ambi mag catches such as Norgon's Ambi-Catch.

Material would need to be removed from the top edge of the EMR-A, or lower edge of the Maritime bolt catch. But even after that, the close proximity of these two control surfaces isn't an ideal arrangement.

EMR-A was designed so one wouldn't need to buy a next generation bolt catch like the ABC/R to use both effectively. The lever's portion immediately below the bolt cache's lower paddle is very low profile, and free of serrations. The lower profile makes it easy to access the bolt catch's lower paddle, even if it's a factory bolt catch.

Below picture illustrates the low profile area of the EMR-A. ABC/R v2 in 17-4 is also shown here, you can see its lower paddle is longer and larger, and angled.



EMR-A with factory bolt catch, Photo Courtesy of Kyle Chanko.

[opngrnd]

Most of what I do is with .mil issued-style musketry, but I've always wanted to see what could be done with a mil-spec level of quality that enhances a rifle's usability as a sum of its parts rather than some kind of gamer style build. After trying the 6315 from FCD, I think I'll try this as well. If small things like this continue to improve the usability of the platform, I'd like to see a comparison between a fully upgraded carbine vs a stock M4 or equivalent.

[26 Inf]

Roger - I get what you are saying about the Mari-time catch. But, got to admit that I tried the Geissele and the Seekins instead of the ABC/R specifically because they had more pad goin to the rear.

Also, despite the swag, I got the 'those little things cost...' from the wife. That's okay though, I was under 'those little things' budget for the month.

[Duffy]

Thank you!

With the 6315, we were squeeze out 20 to 25% (compared to the A2, on which it's mostly based) muzzle rise compensation out of 6315's asymmetrical ports design, all without the flash, noise and concussion penalty that invariably accompanies a comp or brake.

With the EMR-A, it's a matter of refinement and balance.

We set out to make an ambi mag release that wouldn't infringe on Norgon's patent (the design dates back to a time when the patent was enforceable). EMR-A's externally pivoting design is itself a balance act. Its drawback is it pivots on the receiver, but an external lever allows us a great deal of freedom on its size, thickness, and quite importantly, its length. Too long a lever, force amplification means it'll be easy to press, a boon to some, a liability in our opinion. Too short a lever, it can be excessively difficult to press and harder to reach. Too large a lever would also make the lever easier to press (more surface area in contact with the finger).

KAC's long lever is balanced by a small spring under its lever to balance the mechanical advantage, without it, the lever would be very easy to press. As usual, KAC has proven and demonstrated its engineering prowess, this is something most people don't think about.

The eventual standard EMR-A lever, combined with the 10.9lb (60% stiffer) spring, produces a balance of length and pressure required to drop a mag that has thus far been well received. The 10.9lb spring rate spring is optional, it is nevertheless included with the kit.

In terms of usability, balance, and refinement, the original EMR-A design's spoon shaped lever seems like a kid's doodling compared to that on the production EMR-A

[opngrnd]

What is the drawback of it pivoting on the receiver?

[titsonritz]

What is the drawback of it pivoting on the receiver?

Cosmetics, so nothing.

[Duffy]

For those with receivers that cost a few hundred dollars to $1K, they might not want them marred by anything. The EMR-A was designed to go on semi auto and automatic rifles and carbines, not as an accessory for a lifestyle. For those that use their ARs as tools that they are, most of them won't care.