I agree with hurricane, .665 constriction is a good starting point. You'll have to experiment and see whether a tighter or more open choke throws better patterns with different shells. Take a look at the Primos Jellyhead, thats a good choke and pretty reasonably priced. You can pick one up for around 45-50 bucks. Another popular inexpensive choke that does well with lead loads is the Undertaker, you can get one of those for about 20 bucks I believe. My Indian Creek choke just came in, I can't wait to pattern it. Good luck!