I'm trying to decide between getting a 4.25" like the 1076 or a 5' like the 1006. It would be for range/ home defense so I wouldn't need the shorter barrel for carry. I'm just wondering how the two shoot compared to each other: Does the longer sight radius help with accuracy? Are the ballistics that much different? How about the character of the recoil?

There's not much difference. The only way to sense any difference is to shoot them side by side, and even then there isn't much. As for velocity, there is likely as much variance between 2 guns of the same length as there will be between 2 with only 3/4" difference in length.

I would concentrate on finding a nice example of the action type you want (traditional sa/da, sa/da with frame decocker, DAO, etc.) rather than worry about barrel length.

+1. Have shot every example except for the ultra-rare 1046 and I shot the best with my 1066, the shorter barreled version. DA/SA. I sold off all the others and kept this one.

If you look at availability, in general your choice will be between the 1006 and 1076, since they were the most produced versions. 1026's come around every now and then, but the 1046, 1086, and 1066 (my personal favorite) are fairly hard to come by. As a result your choice, if you don't want to look around for a long time, is either the 5" TDA or the 4.25" Frame mounted decocker style. As mentioned by the others, the barrel length doesn't really make a practical difference. Go with the one with the action you like best. Which ever one you pick will be a good one. You just can't go wrong with a 10XX S&W 3rd gen.

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J.D. Roy