1911 Armorer Adventures: Installing an ambi thumb safety

Ambidextrous safeties on 1911s are one of those parts that you see on a lot of guns today that I’d much rather not have. Unless you’re left handed, their usefulness is pretty slim, and they’re not exactly the most durable part. My carry 1911s all have single side thumb safeties, and that’s just how I prefer them.

STI ambi thumb safety
STI ambi thumb safety

Unfortunately, for gun games there are a few good reasons to have an ambi-safety on your 1911. In Bianchi Cup, there is a stage where you start by drawing the gun with your strong hand and transition it to your weak hand. The “best” way to do this is to grab the gun low on the grip so you can make the smoothest switch possible. Shooting a Glock this wasn’t an issue, but with a single action gun, I need to be able to knock the safety off easily with my weak hand.

In USPSA, there are sometimes stages with weak hand only starts, where you’re drawing and transitioning, picking the gun up off the table, etc – all stages that would be made somewhat complicated by having a single side thumb safety. So fresh with knowledge and loaded up on hammers and curse words, I decided to take a quite literal whack at installing an ambi-thumb safety in my Colt CCG. I made sure to have two safeties handy in case I munged one up. Turns out that was smart, but not for the reason I thought.

I started with an STI ambi-thumb safety, because I generally like the single side STI safeties a lot. After some fiddling, I successfully installed both sides of the safety in the Colt. Feeling pretty awesome about myself, I went and function tested the safety…where it failed miserably. Whoops. As it happened, it was slightly oversize and so it wouldn’t engage all the way. It would engage enough to prevent me from pulling the trigger to the rear, but would fail the safety test of “pull the trigger with safety on, then disengage safety.” Disengaging the safety after pulling the trigger would cause the hammer to fall.

Okay, so next I took the spare safety, an older Caspian model that I’d had sitting around from a 1911 I’d had it removed from a couple of years ago. My parts hoarding paid off in this instance, as the Caspian safety dropped right in, and passed all the safety tests. But the Caspian safety has a slight problem – the ambi side (right side of the gun) has a bit of a sharp edge on it, and contacts my hand in a sort of unpleasant way. Initially, I attempted to fix this by removing the Caspian right side safety and replacing it with the STI part, which resulted in a less than spectacular fit. In fact, it wouldn’t reliably disengage the safety when used in my left (support) hand. So off it goes, and the Caspian part goes back on.

At the end, I had a successful installation of a part that I’m not 100% happy with. I have several options now:

  • Use time and careful attention to detail to fit the STI part (not likely)
  • Use time and careful attention to detail to file down the edge on the Caspian part (not likely)
  • Buy a factory Colt ambi-safety and install that (somewhat likely)
  • Use the Caspian part as is and just harden the f*** up (quite likely)

Which option do you think I should pick?