I started with a +5 since it was flush with the end of the barrel on my 24" Stoeger and I didn't know any better. I soon realized that a +6 was a better option since it would allow me to load two at buzzer if need be. Now that I'm loading quads I wish I had a +8. I'll probably end up buying one soon. Moral of the story, take Jesse's advice and get a +8.