20 practical. Faster, flatter version of the 223. Simple to make, but never really took off. 204ruger could be lumped in there as well although it was a bit hotter and requires a bigger bolt face, the smaller bores just never got off the ground. Shame. The 20 practical is listed as a contender barrel by the big guys in the barrel business so I will scratch that itch eventually with EAB or MGM barrels.
On another chambering, I've got an AR-15 chambered in 22x6.8. A wildcat round that never took off.
I’m just hoping 350 sticks around. I just did a caliber swap to it for doe hunting this year.
20 practical. Faster, flatter version of the 223. Simple to make, but never really took off. 204ruger could be lumped in there as well although it was a bit hotter and requires a bigger bolt face,