[Lovesbeer99]

I bought a used 870 Express youth gun with 21" barrel. I'm short so the gun fits perfectly when I mount it. I considered getting an 18" barrel, but instead I kept it at 21 and bought a 3 shot mag extention. You can't get 3 extra with an 18" tube.

Any opinions on 21" vs 18" or 7 shots vs 8 shots?

[41magsnub]

Frankly... either would be fine.

Personally I use a Winchester Model 120 20 ga with a 21" barrel without an extension (I doubt there actually is such a thing for that gun) and a 5 round butt cuff. 5 rounds with 5 reloads seems like plenty to me.

[Rshooter]

I have both a 20 and an 18 inch gun (870 police). Truthfully I cannot tell the difference between the two. Some will tell you it makes all the difference in the world but really an inch or three is not that much. As far as the magazine extension learn to load as you shoot. An really if you cannot do the job with four and 911 you are most likely doing something you shouldn't be doing anyway.

[goon]

I'd say either too. My mossy only holds 5. I only load it to 4 because that way if I need to switch to a slug I can just stick one in the mag and rack the slide.
But I feel entirely confident with those 4 rounds of 12 gauge.
I think a 20 gauge would still give that warm, fuzzy feeling.