Fightingfish
.40 S&W
Tapco, as much maligned as they have been over the years, sells a damn fine armorer's wrench. I have one, works great. You don't need it though. The punches used to install those roll pins will also work to install the castle nut if need be. Or any spanner wrench that fits works also.
Pro tip, install anything with a spring and detent in the shower with curtain closed and drain plug in. Easier to find that stuff when you inevitably try to beat space x into orbit. There are other methods, but this is quick and easy.
I also like the spikes tactical tool less trigger guard. Those ears on the lower are the most likely place to break something. Otherwise just don't pound on the thing like a gorilla and you'll be good.
Yeah, flying springs and pins are fun. The first time I took apart my Ruger (my first semi auto), I idiotically hit the trigger with the lower pulled off. Finding those pieces was a blast. Lesson learned, though...I’ll never make that mistake again.