I was wondering if anyone seen, heard or have the stern defense 9mm adaptor "MAG-AD9" that converts your AR 15 into a AR 9/40 and shoot 9mm or 40 S&W. the adaptor uses glock magazines and is a plug and play with a 9mm or 40 S&W upper where there is no modifications to your lower receiver and has the last round bolt open hold "LRBHO". the only downside is the price tag of $179.99 for the adaptor where some dedicated 9mm lower receivers cost the same or less. https://getstern.com/
I’ve never heard of this one but it’s not a new idea. I have several thoughts about pistol caliber carbines. They need to be light and short. IMO a 16” 9mm ar-15 is just too over weight too be useful. If I am getting something that’s rifle sized, I want it to use a rifle round. A SBR would be a be my choice for an AR-15 in a pistol cartridge. I own a Beretta cx4 and a Marlin 1894c. The Beretta is short yet not NFA and it’s very light. The marlin is short, a little heavier but balanced perfectly. It also shoots a more powerful cartridge. I don’t want to discourage you but there are trade offs. Stuff to think about.
no I'm good I'm looking into a pistol build and just deciding on a 5.5 or 8.3in barrel because anything over 10in in a pistol caliber would be overkill and defeat the purpose of a pistol caliber rifle.
The question of cost becomes less of a concern when quality comes into play. For example, the cost may seem high compared to some of the bottom end company 9mm lowers, but if it works well and I can use it with my existing SBR lowers, it is fantastic.