As noted, it is legal. As long as the barrel is less than 10" it is competition legal. Is it necessary to have a long barrel? No. If you are intending to shoot using iron sights, however, then the longer barrel will provide a longer sight radius which may help accuracy. Nowadays many, maybe most, Bullseye shooters are using red dot sights and the need for long sight radii is not a factor.Is The Ruger MK III 22/45 legal for bullseye competion with the 6 7/8" barrel? I