I've got a case of hevi bismuth #2 3" 1.25 oz loads ive been trying to pattern for duck season and looking for some help. Looking to shoot them out of an sx3 (invector plus) and browning b80 (invector). Started with both guns in an extended range carlson .710 and .700 respectively. Patterns weren't even 50% on 3×5 patterning board at 40 yards. Didn't have anything tighter until turkey chokes in other guns. Went to an 870 and Charles daly to do some testing and shot an undertaker .675 and tight wad .660. Patterns were about 60% 30" circle but uneven with a fair amount of flyers.my hunch is im overchoked at this point and need something in the .680 range but looking for any suggestions I can get. Normally, I'd just buy chokes and test until I found what I liked but I've never been a fan of anything hevishot anyway and only have a case of these and it will be my last so im just hoping to find something usable to get these shot up.

Try using a more open choke....

I should've mentioned that. I started with improved cylinder up to light modified in the sx3 in the factory and carlson waterfowl chokes. All were as bad as the extended range carlson mentioned and saw the patterns improve from that to the turkey choke which was what gave me the inclination that somewhere between the full carlson and turkey choke I where I need to be. I do have a couple straight cylinder chokes I could try but with the testing I'd tried at that point made me think I was going the wrong direction.

I don't have much to suggest.

But, I shoot a lot of 1 ounce bismuth loads in a 16 gauge and it works great. Mostly an IC choke...or Mod on my 2nd shot. I'm shooting pheasant over pointing dogs. I don't take 40 yard shots, generally.

Interesting that you had similar results in that many guns.... Bismuth tends to fracture so maybe the open choke would actually help,
,,,or, sell off that case and forget about it, lol

I'm out of ideas...

Cut’em open, dump Bismuth, reload with #4 lead, crimp’em back down, kill ducks.

Well fellas your responses thus far are about what im coming up with too. I have never been a hevi shot brand fan and picked these up cheap, hoping to have something to get me by. Have been loading tss the last couple years and just have a hard time going back to steel on some of the late season diver hunts we get in to. But with the tarrifs its really priced me out of that game. I have done quite a bit of patterning and these shells have me perplexed. I was just looking for the cylinder choke I have and did find an old patternmaster long range I use to use for geese. It uses the stud rings instead of constriction so maybe coming at it from a different angle will do the trick but, I don't have high hopes, that choke loved the old federal 3.5" t shot and has been adequate at best with anything else I ever tried it with.

Just out of curiosity what’s the velocity on those shells?

1450 fps. I did a little more work yesterday and cut open a shell out of curiosity. I knew better than to buy anything heavy brand but did it anyway and found the payload to be short of advertised. I counted 120 pellets vs the 140ish that should be in there given the pellet size and payload. Thats not a deal breaker given the inconsistencies in bismuth pellet size in general but I do know now that all my patterns will be missing 20ish pellets from what I was expecting and to judge my patterns accordingly. I did shoot the patternmaster I had on hand yesterday and shockingly it gave me a usable pattern to 40 yards. Kind of defeats the purpose of what I bought it for but at least I have something good enough to be able to get it shot up as all patterns before that just weren't usable. May do a little more testing. I reached out to trulock as ive had really good luck with them in the past and they're good people to deal with. Im still thinking something in the .680 constriction range in the sx3 may be the sweet spot as the .700 was all over the place and the .665 was much tighter but lots of holes and flyers leading me to believe its overchoked and blowing patterns at that point.

i have noticed a modified choke usually works the best with any waterfowl load except back in the day when we could use lead

Here's a couple comparisons of where I'm at with it. The one is with the patternmaster that I consider usable. The other is by far the best pattern I had up to to the point of the patternmaster and I believe it was more of a fluke as I shot that same choke and gun 3 other times and had in the upper 40's in the 30" circle, anything under the .700 constriction was in the 30's-40's on the entire paper at 40. The good news with all this headache is by the time im done pattern, ill only have half a case left to get shot up.

? I'm shooting an X3, stock or pattern master ICL and getting excellent patterns out of that particular brand and losd Plus BOSS legacy ammo. Although I prefer the 1-3\8 oz load. I found a great deal on Fiochi bismuth as well, hated it at first , but figured it out eventually. By the time I was thru a box I was hammering ducks at 45 and cleaning up escaping crippled ducks at 60

Thats part of these shells that has really been frustrating. The only bismuth ive ever patterned before were kent #5 and the winchester I believe #4. The Kent's shot well with the stock modified and the winchester patterned great with anything from improved cylinder to modified. I only had a box of each of those and wasn't enough for a fair test and went to a .410 with tss the last couple years. So with tss prices out I bought these with what little bismuth I had shot in the past and the bigger pellets these would do well with a fairly open choke, but every pattern ive shot has shown they want tighter at least to a certain point. I will say, cutting open that shell and realizing im dealing with 20 fewer pellets than they advertise does make things look a little better. That puts the patternmaster long range with a 70% pattern which i can work with.