The extended turkey chokes I believe go down to .660 ( 12 ga ) not sure if some one makes one tighter than that. By comparison , standard full choke is .690
Hastings used to make one down to .640 for Remington, but they didn't pattern so great, and put a strain on the threads ( Barrel )
The tighest choke tubes are the long range turkey chokes. Many manufacturers make them, so the brand is between you and your wallet. All of them should have a decimal diameter of the constriction, that you can compare among brands. That's the way to find the tightest.
But I understand that if a choke is too tight, it may cause the pattern to open back up again. It seems to compress the shot bolus which then springs open after it's past the choke. No way to tell until you pattern your loads in your gun with your choke tube.
Go get a Tru Glo .665 and don't look back. Mine shoots great with a .670 and .665. 670 is Mossberg and 665 is Tru Glo. Long Bears, Federal 3" 2 oz Turkey and Estate! turkey loads all shoot well. And the tru Glo is only about $25!
Check out Trulock chokes. Absolutely the greatest company to deal with. George Trulock will answer emails too. And if everything isn't just exactly right he will make it right. If I buy chokes I buy from him, period. And the patterns are great too.
Thanks for the ideas folks. I was looking at brilys chokes but I wasn't sure how their sizes compared to the factory sizes. They didn't give numbers like .670 or such. They have numbers like .035. I'm assuming that's the thickness of the metal they used to make them but I've been wrong before.
Is full always the same constriction from every company?
The number ( such as .035 ) is the amount of constriction. For example , a 12 ga bore is around .729 Dia. , and nominal full choke is .690, that would be a constriction of about .040"
Extra Full turkey chokes are even tighter than that with many around .660 or so.
Now the total constriction is .070 or more.
That's why the " tighter than full " chokes are often extended, to help the shot be more " fluid like " and to help with bridging ( shot getting jumbled together as it goes through this funnel )
Choke companys are always trying to come up with better ways to get patterns to suit us.
Choke and patterns are also affected by shot size. Generally speaking larger shot needs less amount of choke.
The only way to know how it will pattern for you is to try different load/ choke combinations. " tighter" choke constriction is not always the answer
True! Too tight can blow your patterns. The extended choke tubes in all constrictions usually, not always, but usually improve patterns too. The reason is that most extended tubes are conical/parallel in construction. There's a constriction section and a parallel section to help better align the shot.
The "Super Full" chokes are designed for turkey loads which are in themselves often a specialty load. Usually lots of shot and low velocity with smaller pellets like 5's. The current "standard of .030 for a full choke is fairly recent due to plastic sleeves. They could also be a detriment to other types of hunting and are definitely not for steel or Hevi Shot. There are also different Mossberg models. The standard for the 500 pump gun, a different one designed for steel for the 835 and their SA equivalent and some foreign Turkish tubes for the Silver Reserve. I have the 835 and a Silver Reserve. Tru Lock is a very good supplier of chokes and has charts for reference.
Here is your problem. Chokes are described in engineering terms but perform in artistic terms. For example, the effect on the pattern varies considerably based on things other than the constriction. I can make a full choke perform like a cylinder bore and a skeet choke pattern like a full choke. Hard shot, sho tsize, the wad used, velocity of the load and probably several other variables effect the delivered pattern more than the actual choke measurements. The extended chokes are a marketing ploy (sucker appeal). chokes have a constricting cone shaped entry followed by a short parallel section. Make the parallel very long and the shot column will assume the new bore dimension and come back to cylinder bore performance. For an example, I use Dead Coyote T shot for predator hunting. Full choke is not the best with this and a modified choke throws the tightest pattern. The only way you are going to know which choke gives you the tightest pattern is to experiment with several constrictions using the specific brand and shot size and shot hardness you have selected for the hunting condition. Most choke producing companies setup their patterns with shot sizes used for trap, skeet and sporting clays. Probably too small for your purposes. If you have some tubes already, pattern them with the range you want and the loads you choose. You may very well already have as good as you need. Most guys are over choked anyway for their shooting skills. If you want a really tight pattern shoot a rifle.
Update: after looking around at the options and listening to advice on here. Plus just generally looking around on the internets. I decided to give trulock chokes a try. I bought an extended ported turkey choke. Way tighter than the factory full. I played around with it with the factory target loads that I had laying around. Way better pattern than the factory chokes. I think this will end up being a great turkey hunting choke. Thanks for the advice folks.