I don't see the appeal of a Howa Mini in 22 ARC. The reason being that a bunch of us are going to replace the bottom metal anyway. With that being the case, we eliminate the primary appeal of the 22 ARC over the 223, namely fitting longer bullets into a magazine, since the ARC and 223 length Jefferson Outdoor mags are both 2.450”. The velocity advantage of the ARC over the 223 isn’t great, and certainly isn’t enough in my mind to overcome the vast logistical advantage of the 223.
The only place I could see the 22 ARC being an advantage over a 223 in the Mini is for the guy who only shoots factory ammo.
