Love the defiance, I was a little concerned at how thin it was compared to the bipoly but it works great. You're gonna love bipoly, make sure to do the bushing version. It's plenty strong and much easier.
The Orca is a custom lower/upper pair, look into things like the Bi-poly, the UbarX, or the SL-15 for standalone lowers that can mate to standard uppers.
It might be a rough search. Gen 5 market adoption has been slim and isn't looking like it'll increase much. CA's new glonk ban might even hurt a lot of the gen3 aftermarket.
Respectfully, if you're into ARs, do a bipoly. It's by far my favorite AR lower, cost is about $100, I've had mine for over a year now, has ran about 2k rounds through it, I'd trust it with my life. It pairs with any upper you want, I use it with a bca 5.56 upper and a cmmg 9x19 rdb upper.
It helps a lot with threads, and under/over extrusion. If you need the files DM me, you're not supposed to share them cause OP has cancer and he sells them.
If I recall correctly, he oriented the barrel nut super weird, with the bore facing sideways. I did mine vertical and it threaded on fine but he had a good reason for that orientation.
Have you done dimensional calibration, like a calilantern?
I just looked through guncadindex, I don't see anything for a drop-in, but it looks like it physically should be possible. The cam just needs to push on the back end of the trigger shoe, and the leg could be tuned easily via the step files.
Look into the monstrum lvpos, they're super low budget. I fuck with vortex too but sometimes you just want to build something to magdump trash and monstrum is where it's at for that.
For an AR, I'd recommend an lvpo with an offset dot, or a prism with an offset dot. For the bolt action, the lvpo will be fine by itself. They're good out to the maximum range of 223/5.56 easily. I use a 1-6, but 1&2x are basically pointless. The 4-12 sounds perfect. I prefer FFP, SFP is kinda weird.
Quick question, why would you need a cut trigger? Mine function tests with an unmodified milspec trigger and the docs never mentioned any trigger mod. As far as I know that's just a hoffman thing. Same with the rounded off detent. I used a pointy one with the kak 3pos selector and the jig to file it.
Love the defiance, I was a little concerned at how thin it was compared to the bipoly but it works great. You're gonna love bipoly, make sure to do the bushing version. It's plenty strong and much easier.