AR-15 22lr build

[historian]

So I have a stripped lower sitting in my safe. I was going to go 300BLK, but I'm never going to be able to afford a 2 stamp gun, so I'm thinking about making it a .22 for plinking. I know I need a dedicated 22 upper, but I can't find any info on a lower build and I don't know outside of the BCG what would be different. Any help pointing me the right way would be appreciated!

 

[tcecil88]

I have one of these that has been absolutely awesome. I built it for Squirrel hunting. With CCI Mini-Mags it will do dime sized groups or less @ 35 yards.
https://www.bearcreekarsenal.com/calibers/ar-22/ar-22-complete-uppers.html
Currently out of stock, but I'm sure they'll get more built. They are heavy as the only thing they seem to put out are heavy profile barrels, presumably to keep the cost down. They had a QC issue where the early ones were being machined too thin on one side of the chamber and as a result they were getting case ruptures. Mine does not have this issue and you can check it visually to make sure it was machined properly, which was the first thing I did when I got the upper.

 

[jwamplerusa]

I to have a BCA side charger sitting on an INGO lower, with an ambi-safety and mag-catch, and MBT2s trigger.

It took a replacement BCA upper (first barrel had railroad tracks in it) but it shoots well enough.

The only difference between the BCA upper and any other sitting on a lower, is there is no need for a buffer weight and spring. You do need a full power hammer, as I found ignition to be nearly zero when I mated the upper with a KP15 lower with an SLT trigger.

I also reshaped the firing pin to concentrate the force more toward the rim of the cartridge which helped with ignition reliability with harder brass (Federal).

 

[historian]

Thanks for the tips. Do you have to do anything special with the lower build, or is it just a normal lower and all the magic is in the upper?