Rockdoc, the difference between Mod and Full in a .410 is .005-.007 at best according to Briley who make most of the choke tubes today. Winchester were known for boring their guns slightly more open and Browning more tightly. If you measure factory 42 chokes they are all over the map. Perhaps because owners opened them up over the years, perhaps they started more open then we expect, I just dont know. I have several 42, both mod and full with chokes which differ by as little as .003. I know you pattern you guns to see real performances and so do I. And if you want to see peoples eyes glass over talk about ten patterns of each load. I think most of these shooters think being able to hit a sign, along the side of the road, is still a good way to check both POI and pattern.
As to starting a new shooter out with a .410 I am in agreement with those who feel any .410 for a new shooter will frustrate them too quickly regardless of the choke. Better to use a 20 or 28 with 3/4 ounce shot, to have a working pattern, for high number of breaks. Plus 20 ammo is cheaper than .410. I started out with a 28 and so did all my kids.
I do see a few old farts who seem to preach that the .410 is capable in all hunting situations. It clearly is not in my mind. It handicaps a good shooter, makes him work harder to remain as good as others using bigger bores. With a 12 gauge, in early season I probably could shoot my limit with 15 shells. Birds are easy until they get educated. I shoot .410 to make it last and to challenge myself to shoot better. If fact you need to restrain yourself to taking better shots with a .410 because it is not the equal of its bigger brothers. If you can do that with a Mod or Full choke gun more power to you.
