So I am building my first AR. This will be the first I have ever owned, except a MP 15-22 that I never did much with except shoot a little.

I built the lower myself. Ended up ordering a complete PSA Upper (Got a good price and didn't feel like taking the time to build one).

By question is about the adjustable stock.

It will only adjust to the three shortest positions. When putting it on, it slides right past the first three holes then locks in after the third.

I have this for the stock - Magpul MOE Carbine Stock - MIL-SPEC

https://magpul.com/firearm-accessori...obal_color=118

And
MOEŽ Carbine Stock * Mil-Spec
https://magpul.com/firearm-accessori...obal_color=118


Any idea what the issue is?