I am looking to build my first AR15, I currently own a store bought AR without a pistol grip or collapsible stock.  I want to build a Fixed Mag fun so I can add all the accessories I want.

I know Dark Storm makes a billet fixed mag stripped lower but they also charge a pretty penny for it.  I see other do it yourself kits to convert any lower into a fixed mag.

In order to stay in Compliance for NY and having a fixed 10 round magazine.  What are my options for lowers?

There were a few kits I saw online that log the magazine, but if you pull the pin to open the upper / lower you can then remove the mag.. are these legal?

example:

https://www.80-lower.com/products/armaglock-ar-15-magazine-lock

https://www.brownells.com/rifle-parts/receiver-parts/magazine-parts/magazine-releases/ar-15-freedom-fighter-fixed-magazine-conversion-kit-prod107892.aspx

I used a 10 round Pmag gen3 magazine as the base plate is removable. I used an AR Mag lock and JB weld over the allen head screw holes. ATF came out and looked at the lock and informed my judge that it was good to go and it is now on my pistol permit. I use MEAN loaders and one other to load it   http://ddsranch.com/ar-15-magazine-lock/

I would just move

Wow that's such helpful advice, I'm sure the OP is very grateful!!

How would NY feel if someone drilled a hole in the side of the mag well, the side of the 10 round mag, and tapped the mag well hole and put a socket head screw in it?  Then buy a standard mag release and grind off the part that holds the mag in? That would render the mag release useless, and would replicate exactly how most semi auto fixed mag guns are done (a screw holding on the magazine or tube).  Just saying that would seem like a way to make it complaint and not a total pain in the butt?