chokes and effective range

[homers]

Question about chokes and effective range when it comes to shooting clay pigeons. What's the effective range of each choke type, 20 and 12 gauge, with 7.5 or 8 shot? By effective range I mean will bust the pigeon.

 

[oneounceload]

http://www.briley.com/index.asp?PageAction=Custom&ID=51

12 through 28, all chokes...scroll down for different targets as well...this is from Briley