Boofer, smaller bore and less shot then a 20 or 12ga. Hence the smaller pattern. That and it also depends on what choke your useing. But then small tight patterns are GOOD.
And don't be deceived. 410s shoot HARD and WILL shoot just as far as a 12 or 20ga.
For wacking squirrels n rabbits with headshots i LOVE a good full choke 410 with #4 shot.
Kick it up to #8s and you got a good dove gun. Especialy if you got a Modified choke.
For home defense #4 or #2 bird shot is good. Best is a buckshot load with 3 #00 pellets. Modified or improved chokes the best.
I know some guys that have even taken up turkey hunting with them as a challange to their hunting and calling skill.
I DON'T reccomend that for anyone but a real HARDCORE experianced turkey hunter.
The Rossi lever shotgun is smooth bore. Made strictly for 410 shells. You'll only see dual purpose shotguns with rifleing. Rifleing in a shotgun(except for slug guns) will really screw your pattern and accuracy up. Spins your pellets to the outside and leaves big holes in the pattern. Paticularly the center.
As for reloading, especially 410s, unless your shooting a LOT your better off buying boxed in the store. 10s, 12s, 16s 20,s and 28s are'nt bad if you shoot a lot. Even then 410s are a pain to reload.
He!! id rather form and reload wildcat pistol rounds like my 7TCU, .30 or .357 Herrriets then 410s.