Decided to try a super tight choke with some light loads.

[3" 870 Shell Shucker]

OK, the outcome of all this was:

I tried a Kick's .650, Ventilator .655, Indian Creek .665 with ports and wad catchers, and an Indian Creek .675 without ports or wad catchers.

I used 1 ounce #6, #7.5, #8 loads, and 1 1/8 ounce #7.5, #8 loads.

Indian Creek .665 with ports and wad catchers gave the best "card target" patterns.

Indian Creek .675 without ports or wad catchers gave the next best "card target" patterns.  Dense core in the pattern, etc.

That left the Kick's .650 and the Ventilator .655, both of which gave nice hunting patterns.  The .650 seemed to do well with all of the 1 ounce loads, giving nice tight even patterns.  The .655 seemed to like #7.5 and #8 loads.

Still, even 305 in 5" x 5" at 60 Feet using a 1 1/8 ounce load of #8 Lead was met by criticism on the card shooting forums, insisting that you need to be blowing a large hole in the target at 60 Feet.  If that's so, then my idea of competing with a true stock gun using a screw-in choke seems doomed.

[gobblingghost]

Are you wanting to shoot a stock gun in the open or wildcat class of targets?? The shoots I have been to in the open class they don't messure the number of shoot, they see how big is the hole.

[3" 870 Shell Shucker]

Are you wanting to shoot a stock gun in the open or wildcat class of targets?

No.  I was hoping that such a thing as a stock shoot existed.  But evidently, everyone either tries to cheat at stock shoots, or else shoots in the open class with pro stock guns. 

[3" 870 Shell Shucker]

I'm not bitter about it.  It is what it is.

[SumToy]

3" 870  Stock is a funny word in my world.  I will tell you I only of 2 shoots that are stock.  Then most of the time we can find that gray area in the rule. 

Now the site you was on is the one I think some of them will feed you a line to sale you something. Some will feed you line to try to get in your head to.  Now like I said before at 60 ft with 9's we can blow a hole with alot of stock barrels with just a choke.   Now they shoot 60 ft from trigger line.  That was why I shot the targets at 63 ft.  You shot from end of barrel.   

The targets you had I would take to a shoot.  Now can you have better yes you can but if you only shoot a few times a year take what you have.  It will stand up fine.  Take this from a target shooter it is ALOT of luck when you shoot to the X after you get 60 ft and out.  I would take a target like yours with alot of shot then a target with a hole in it.  Hard to keep that hole in the center with rifle sights and leaning on a board. 

[3" 870 Shell Shucker]

The targets you had I would take to a shoot.

I couldn't find any #9's in the county I live in, but perhaps they would have been the key to blowing holes consistently at 60 Feet and out? 

Still, I know the 1 1/8 Ounce Top Gun #8's are used at some shoots, so I was working with a relevant shell.  I also tried some #7.5's and even #6's, because I might actually hunt with those. 

The Indian Creek .665 was blowing some small holes at 63 Feet, and it gave the most center dense patterns, of the chokes I had on hand.  One thing I saw was that a choke with wad catchers is an advantage.  I don't think my success with that particular choke was all due to the .665 exit diameter.  5 wad catchers, and possibly even 30 parallel ports probably had more to do with it.  Although, the Indian Creek .675 which didn't have catchers or ports was my second best performing choke.  (An Indian Creek choke between .660 and .650 with catchers and ports would probably smoke some 60 Foot targets.)

However, I also realize that SumToy Customs builds chokes, and I appreciate all of your input on this thread.  I'm sending you a pm about something else.

[SumToy]

3 inch it will not let me send you a message.  I will email it to you if you get me a link.