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.