I’m loving the ambi mag release on 2 of my billet lowers, the CMT TAC, and the San Tan Tactical. Both put the button in the right spot and both are easily manipulated. But I’ve got a few forged lowers with no accommodations for the left of hand. There are few good ambi catch out there:
I skipped the Norgon, because it looked like there is little mechanical advantage to the system, and would require more effort use with one finger. I also passed on the KAC, since it seemed to busy, and likely to catch on something.
I put the Troy ambi on my Aero lower. And it does just what you want it to do. It’s out of the way, but accessible. There isn’t a lot of extra effort needed to drop the magazine, and it doesn’t look too prone to accidental drops either. It’s lower profile than the HVA, and doesn’t get in the way of a standard bolt catch. The only thing problem I can see is that it may mark, or start digging into your lower for it’s leverage.
I put the HVA AMR on my Stag lower. It’s bulkier than the Troy, and it is quite close to the bolt catch. It has a very smooth action, and doesn’t require too much effort to drop the magazine. If you’re smart, and already replaced the bolt catch with Forward Controls ABC/R, then you’re also in luck. While it sits close to the bolt catch, it’s not in the way, and easily accessible.
It’s tough to pick between these 2 bolt catch’s, and I haven’t decided which one fits my hand best, but both work well enough to stay on both hosts.
I’m a lefty, and as a lefty, I have the need for ambidextrous controls. I don’t want them, I need them. With some Ambi Mag catches, the lower paddle is obscured from easy access. This is why I bought the Forward Controls Augmented Bolt Catch/Release, Forged or ABC/R-F for short. It’s a really nice piece of work. It’s a well made drop in replacement, but better. With the added material for the oversized control, they have removed some interior metal to bring it down close to the mil spec weight. It’s an easy drop in replacement. Nothing needed to be modified, it was pin out, pin in, and done.
Once in, the new tactile feel is great. It’s an easy hit, and when handled left handed, a simple index finger push to the improved lower paddle is all that you need. I’d even install it for other lowers that don’t have an ambi mag catch, or have one that doesn’t obscure the catch like a Troy. The additional angle to the over sized upper paddle is a nice touch too. Even with thick gloves, it’s a cinch.
This is the kind of improvement that should just be spec’d from now on. I didn’t know I needed this, and now I’ve put it on all my rifles.
I’ve been shooting a left handed Stag AR-15 for a few years now, and wanted to build a new true left-handed rifle from the lower up. The Stag is great, but it still rides on a standard right handed, non-ambidextrous lower. Thanks to the fine folks at CMT-TAC, the’ve come to the rescue with a great full ambi lower.
The UHP15A lower has everything you’d expect for a great billet lower:
- Full Ambi controls: Bolt catch and mag release:
- Threaded bolt catch pin (no roll pin installation needed)
- Integrated oversize trigger guard
- Compatible markings for 45° safety selector
- And generally great manufacturing
The Lower Controls
First we’ll start out with the ambi mag release. It’s gated to help prevent unwanted mag drops, and is easily accessed and manipulated with your left index finger when holding left handed. The back side is conjured to the trigger guard, and has a bit of a point, so It may snag, but that hasn’t happened to me yet, as I’ve only bench shot this rifle. It’s also set up so you can use a standard LPK mag release. No special parts are needed to build up this rifle.
The ambi bolt release on the side works just as well. While operating left handed, I like to close the bolt with my right thumb, it just feels natural that way. It’s also situated behind the dust cover if you have a standard wrong sided upper on the the rifle. If you’re holding the rifle right handed, and have an extraordinarily strong index finger, you could close the bolt. If not, two fingers will work.
These controls are the main reason to pick up this lower. The rest of the lower is a well made billet lower. The maxwell is flared, the integrated trigger guard will let you wear gloves, and it fits like a glove with my upper.
The only improvement I would add, is a threaded rear take down detent hole. My Aero Precision forged lower has this, and it’s great for the build. Even better when you decide to take off your buffer tube and forget the dentent and spring are still behind the end plate.
Now that you’ve got this lower in hand, you can only make it better better by putting a UPUR-1LH atop this.