I won't use a poly lower on any AR I have seen them blow the side out right at the magwell next to your face if cheek wielding at the moment which I would hope you would be.
I have one laying around that was an SBR build until I saw the exploded ones that company stopped producing them as well as bushmaster used to build one a long time ago I believe.
Stick with a good forged lower for safety and long term durability,
BTW if you might know I was fiddling with this shit for 25 years as my daily tool kit.
PSA is cheap and will throw lead downrange get and extra CH and a high quality extra BCG and buy mags now before shitface bans em