I have had an orphan AR-15 top end residing in a closet since before the election. I noticed Denny at Global Tactical Supply, North Kansas City, MO, had some more lower receivers in stock, so I ordered one earlier this week.
It seems as if every place I check is out of lower parts kits. I have some parts, but nowhere near an entire set. I plan to use an Ergo grip, Magpul curved trigger guard, KNS Precision push-button pivot and take down pins and JP Enterprises anti-walk hammer and trigger pins. That will eliminate the need for several parts in the kit, but it never hurts to have some extras for the other AR-15.
For now, I'm going to use a Bushmaster A2 butt stock that's also buried in the closet. The top end has a bull barrel and the A2 will balance it out better than Magpul CTR or M4 collapsible stocks. Maybe I'll try a Magpul UBR stock sometime. It is convenient to have a stock with adjustable length of pull in this part of the country. Yesterday morning it didn't get above 10 degrees before noon. Today it's in the 60s. The thick Carhartt coat is hanging on a brass hook.
I've been eyeing the 6x45mm round, which is simply the .223 necked up to 6mm. It is legal to use for hunting whitetail deer here, where the .223 is not. Mainly, it is something I'd like to experiment with--even more fun than what we had with Lincoln Logs or Tinker Toys back in the Stoned Age of the 60s