PDQ Ambi Bolt Release Verdict?

[BillB]

Yeah, this has me on the whole full ambi kick again. Operations Parts has a pre-order for another run of Radian ADAC lowers.
Does the LMT MARS have the same functionality as the ADAC? ie the bolt lock back with the right side mag release?
Honestly both look great and I'm sure both are top quality but honestly, I much prefer forged lowers. Some billet receivers loose the look for me. I guess I just prefer the mil look.

[justin_247]

Does the LMT MARS have the same functionality as the ADAC? ie the bolt lock back with the right side mag release?

The two are... different. With LMT, the bolt catch is almost literally a mirror of the catch on the left-hand side and you manipulate it exactly the same way to drop the bolt or lock the bolt back, just with your right-hand.

With the Radian, the function is split up between two buttons... it has a dedicated button on the right-hand side to release the bolt and the magazine release button doubles as a bolt catch.

[mig1nc]

The two are... different. With LMT, the bolt catch is almost literally a mirror of the catch on the left-hand side and you manipulate it exactly the same way to drop the bolt or lock the bolt back, just with your right-hand.

With the Radian, the function is split up between two buttons... it has a dedicated button on the right-hand side to release the bolt and the magazine release button doubles as a bolt catch.

So, with the Radian you have to drop a mag to lock the bolt back with your right hand?

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[Duffy]

A-DAC works by using an actuator rod, the mag button pushes it diagonally and moves the bolt catch. Both the mag release button and bolt catch have to be modified to work, the receiver needs the channel for the actuator rod as well, so all proprietary components.

Redi-Catch replicates this by using an S shaped spring, and a modified bolt catch which holds the spring. The spring reaches up to the back of the bolt catch, when the mag release button is pressed, the spring pivots the bolt catch down, locking the bolt carrier back.

The problem with Redi-Catch is it precludes the use of any ambi mag release, Norgon, KAC, Troy, our EMR-A, because the mag catch plate is proprietary.



The interesting tidbit (to some, maybe) is Redi-Catch's use of another spring adds to the pressure required to press the mag release button. In addition to the mag catch's own spring, the mag catch now has another spring that adds resistance, it feels about twice as hard with a Redi-Catch installed. I first noticed it, and realized this isn't a bad thing, but something I wanted. The factory spec mag catch spring is rather weak, it's not hard to accidentally drop a mag, especially if you have the rifle slung, with the ejection port facing your armor with pouches and gear attached.

With our EMR-A, we use an extra power (calibrated to 30% stiffer) spring, which we also make available separately. Much to my surprise, these extra spring rate springs are quite popular on our site.

[Dennis]

I really like both the ADAC lowers and Redi-Catch. Dropping the mag prior to locking the bolt back makes sense for both immediate action and administrative functions. I was pretty quick locking the bolt back the old way but these make it quick and easy with no shifting grip/aspect of the weapon.

I like the drop in simplicity of the Redi-Catch but the ADAC is cleaner. I was also able to modify larger/nicer bolt catches to work with the ADAC lower so you don't have to stick to the boring standard paddle OEM one.

I wish I was able to procure a full ambi lower before our state rights diminished in 2016 but they were rare back then...

Dennis.



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[justin_247]

So, with the Radian you have to drop a mag to lock the bolt back with your right hand?

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Not exactly... with the Radian you have to drop a mag to lock the bolt back with your right hand if you don't want to remove your right hand away from the fire controls. You can always lock the bolt back with the left-hand bolt catch if you don't want to drop the mag.

If you think about situations where you may need to lock the bolt back with your right-hand, particularly certain kinds of functions to correct a malfunction, the ADAC makes a lot of sense. I really can't think of any situations where I need to both quickly and manually lock the bolt back WITH the magazine in the weapon.

[BillB]

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These show my minimal modification to this particular lower. It seems to do what he said it would do. Like some others I don't care too much for the shape and it's slightly concluded by the FA but I have plenty to engage and work the device. Overall I guess I'm happy with it. Plus I got a small discount due to receiving the nickel one instead of the black finish.
When I run one of my slick side uppers on this lower it becomes even more easily manipulated and is quite fast with practice.
I had it for quite the while after buying it because I chickened out and couldn't bring myself to chop a new BCM lower for it but when I got this lower and saw how it was machined there, I knew I had found the perfect candidate for a PDQ.