Hello everyone and Happy Easter...

I am new to the AR platform, so please ignore my ignorance. This newbee needs some solid advice and input. Pre 2000 I had purchased a few Armalite M15A2's that have been sitting in my safe for 20 years and never been fired. I want to leave one alone and modify the other. I am looking for high quality, bolt on parts. My thought was to replace the upper with a flat rail complete upper and barrel. I want to keep it CA Legal so 16" is the shortest I can go. I plan to use this rife for range time and home defender.

I have done a fair amount of research and am leaning to a Bravo Company complete upper, they appear to have an excellent reputation and a nice price point. Now to my dumb questions.

Will any of the BFH 16" Mid Length upper Receiver Groups simply swap out and be ready to fire? Or are there any other mods that have to be done? What is the primary differences in the rail systems KMR and MCMR? I was looking at the light weight barrels as I don't see the need for a heavier barrel.

In regards to the butt stocks will any of the Magpul butt stocks simply bolt on and swap out or are there any other mods needed?

Thank you in advance... I plan to handle iron sight and optics as separate threads and after I have finish my research.

Happy Easter to you,

Any upper will fit your armalite lower without mods and will be ready to fire.

As for the stock.. what do you currently have? What would you want to install? Fixed or collapsible?
These are the 2 main systems and they use their own buffer, spring and buffer tube. Don’t mix them.

Thanks for the help. The rifle currently has a fixed butt stock, I want to replace with a collapsible. So I will need to replace the buffer tube, spring and buffer?

Yes,
You’ll need also a castle nut & end plate (parts #9 and 7).
When buying the parts make sure the receiver extension is milspec and not commercial this way you’ll be able to mount all sort of stocks.

Are there any suggested kits that have all the parts needed for the but stock?