Re: Longer barrel
Yep. 22 ammo is designed to burn completely in around 16" of barrel (at least that's the length I've heard). After that the bullet is not accelerating anymore, and the friction of the extra barrel actually slows it down.
Meddle not in the affairs of dragons, for thou art crunchy, and taste good with catsup - George of Lod, Year of Our Lord 297
I always take precautions.
Beware the Evil Bullet Fairies.