Yes, it should fit.
I do not think this will work with your PSA AR9, the magazine well looks too long to work as intended.
Thank you for your interest in Troy Industires' products. And yes, this bolt release will work with your S&W M&P 10. If you have any further questions about this, or any other Troy product, please shoot us an email to "sales@troyinnd.com".
The Troy Ambidextrous Bolt Release will not work on a PSA PA10 Gen 3. The extended bolt release at the link below might work.
https://www.opticsplanet.com/phase-5-tactical-extended-bolt-release-v2-ar-10-ebrv2-308.html
The Troy Ambidextrous Bolt Release should work with a BRN-180 Upper.
The Troy Ambidextrous Bolt Release might work with a Savage MSR 15 Recon but I doubt it if another brand ambidextrous bolt release didn't fit. I recommend contacting Savage to see if they may have a suggestion for a compatible bolt release.
The manufacturer doesn't state if the Troy Ambidextrous Bolt Release will work with the Sig MCX Virtus. I recommend contacting the manufacturer to confirm compatibility.
The Troy Ambidextrous Bolt Release should be able to fit and function fine. It is compatible with Mil-spec AR15 style rifles, but to confirm, I would recommend reaching out to the manufacturer of your rifle just for compatibility confirmation.
The Troy Ambidextrous Bolt Release will fit on a SIG M400. Unfortunately, I have not had the chance in install this on an M400 and cannot guarantee that it will not scrape in any way.
Yes, this should work in that firearm.