Does anyone make a solid stock for the MPX. Not a folding one, something like the HK MP5 stock. Going to form1 mine and want a good solid stock. About the only one I see that looks close is the Lage stock, though it's not solid. Does anyone know how the cheekweld is on these? Mine has a SB sliding stock, which is okay, just not the most comfortable. Any help appreciated.

You could use this:

https://www.thordsencustoms.co...r-tube-adapter/.html

This will allow you to mount a standard AR receiver extension, so then you can add whatever fixed stock you want. It doesn't fold.

The factory M4 stock does the same thing. But in any case the folding stock is pretty darn solid even though it folds and I don't have any issues with the cheekweld.

I have a Lage on mine and it is great. It may not be exactly what you’re looking for but it’ll do.