My opinion,

For steel either 3/4 or 7/8 oz. are better payloads for the 20 gauge. 1 oz. 3" 20 gauge reloads will not have a lot of velocity, IF you can find the loading data.

As far as a duplex load of steel and bismuth. Bad idea, pick one pellet type and one pellet size.

If this were my project, I would be looking into TSS and Bismuth and forget the steel in the 20 ga.

YMMV

If you haven't ever reloaded before, there is a learning curve especially with steel and TSS, as the wads are less forgiving.

It wouldn't be a bad idea to get a Lyman 5th Shotshell Reloading manual, not for the data but for information on reloading shotshells in general.

DO NOT buy any components until you know what you need.

 

Well I already bought some Cheddite 20ga 3 16mm brass, primed and skived. They were the only hulls I could find. I also bought some wads. Do you have a reloading book you recommend for data? Like I said any advise is greatly appreciated!

 

If you go to Precision Reloading website, they have reloading data for 20 ga steel, it is listed at the bottom of their web page. Ballistics Products probably has some also, not everyone is a big fan of their stuff. Maybe someone here has steel loading data for 3" 20 ga. Bismuth data can be found on the Hodgdon Reloading site and in the Lyman 5th manual. Precision probably has TSS and Bismuth data, but you will have to ask and probably have to buy it.

 

Bismuth data can be found on the Hodgdon Reloading site and in the Lyman 5th manual.

Bismuth @ 1300 fps +/-, 3's for geese and 5's for ducks. Suggest patterning for your typical distance if you have interchangeable chokes. Some folks suggest tight chokes for bismuth and certainly that might be the case but I didn't know what my loads were doing with various chokes until I patterned them and found a good combination.

Lots of good information if you search "bismuth" here and other forums.

also check out:
Bismuth shot/payload size analysis | Dave In AZ (wordpress.com)

 

The Lyman 5th Shotshell Reloading manual shows 20 gauge loads for Bismuth shot (pages 250-254). For steel shot loads see pages 314 &315. This may give you a starting point but you may have to make adjustments for the components that you have or can get based upon the loads listed in the manual.

 

There have been several postings on the sub j ext in the past month and a half. Go back a few pages until you find them and read.through them. A lot of info in there that won't have to be repeated. As Dogchaser stated, 3/4 or 7/8 are better 20 ga loads. There is great data for these loads. What wads did you buy and what powder.so you have? Impacts advise to get and read Lymans steel section is right on. I shoot 3/4 oz in 2 3 /4" hulls.

 

CSD203 20ga 3" for 1 oz. steel are the wads. I haven’t bought any powder yet. I haven’t found any yet in stock unfortunately. I looked at Precision Reloading website about their reloading data for 20 ga steel. I just planned on getting 10lbs of either steel or bismuth whenever I found powder

 

You can load bismuth easier, more powder choices, than steel. For steel you need Alluant Steel powder. There is some data out there for Lilgun but it uses large quantities, more than I want to put in one hull. Ballistic Products has some data posted for the wads you have listed in their Load of the Week archives. I think they are just 3/4 oz loads but check out those listings. The Precision site has load data for the 2 3 /4" wads. BPI is out of # 3 steel and #5 bismuth at present I know. Have not checked Precision for steel. Rotometals might have bismuth. I don't use much of it so others will chime in on it. Longshot, Blue Dot, 800X are listed in Lymans for bismuth. Long shot and Blue Dot have been available locally for me so it is out there. It

 

Not sure what you are trying to kill or how far but IMO #6s smash everything within 25-30yds. Further if you make a dome shot.
I run a old cut off cylinder barrel.
works great

 

Roger's Sporting Goods has 3" 20 ga steel availble.

 

Lilgun works really well in 20ga it’ll have the highest velocity. The BP tps wad is probably the best wad, it’s the 20ga version of the 12ga lbc43 which is outstanding. The PT series of wad is complete junk and gets holes in the powder cup plus ruptured powder seals. I’m going to start back developing a holy grail 20ga steel load as I have a perfect HG 12ga 2.75” loads and have loaded all next seasons shells already. If anyone has a good tps load to start with I’m all ears.

 

Texcl2, PM sent

 

The cheddite hulls are great. No problem there. Your best investment now is a Lymans 5th manual. It will explain the ballistic differences between the types of shot. IMO around 1400 FPS is where you need to be. Steel shot is a cruel handicap as it loses velocity quickly. It also takes up a lot of space in your shell compared to bismuth lead or TSS. I just put a nice 12 ga load together last fall with the help of the guys here. Good luck

 

My Walmart has 3” 20ga Winchester express shells (bottom of the bucket steel shells) for $22 a box! No thanks, I’ll load ‘em.

 

BPI Advantages Manual has only 5 loads of 1Oz. 3" 20 Gauge. Mostly with Lil' Gun. It does have about a page of steel shot loads from 400-426 gns. One such load reaches 1500 fps with a PT2092. It's load number 130729-4922. That looks pretty good for over decoys in my book. Any long range shooting and I'd be going to a 12 with a 1&1/4 Oz load.

 

That load blows holes in the wads, and blows out the seals. The only way it patterns well is by loading a gas seal to protect the wad. I had awful results with that wad. I made it work with homemade cardboard gas seals and shot ducks with it but you shouldn’t have to go to all that effort, the wads shouldn’t blow out. I also suspect it’s over-pressure, I don’t care what the manual quotes, it cycles my auto loaders violently.

 

I’m shooting a 12 ha 1 1/4oz steel load currently

 

The PT wads have a poor reputation. Over powder cup ruptures and allows gases to vent up through shot with significant loss of velocity. Rio used these in their 3" 20 ga steel loads. Every one I recovered was ruptured. Had the same with the PT 2090's. First batch was great. Wonderful patterns. Second batch shells wouldn't cycle my gun half the time. Finally recovered wads split in two. Much better wads out there. TPS20 the best at present from my experience. CSD is alright but my recent batch is thinner one one side and powder seal is blowing out on the thin side. Maybe choke is tearing it because the loads still seem to perform decent. TPS stays together perfectly.

 

So do y’all think I should go back to the drawing board and just do 7/8ths oz loads? Seems to be a lot more data out there for them. Like I said my biggest issue is finding powder currently, but something tells me I’m not the only one finding these issues.

 

I did, I also tried the wads with bluedot powder with the same results. Just bad wads, some others have had the same results. I started a thread about it last year if you can find it. There is a good sized group that works up these loads for duck hunting, some guys are on this forum but most aren’t. Look around some of the duck hunters forums, there’s a good amount of info accruing for the 20ga. Dave in az (from this forum and others)knows more about this topic than I ever will. Good luck and let us know about your experiences, even if they fail, that’s how we learn!

 

As I stated above, the TPS wad is the best available at this time. Problem is there is very limited data for it. BPI has a little listed in their Load of the Week archeives. The guys on Duckhuntingchat were excited about the 3" CSD wad when it came out, but BPI only provided 3/4 oz data. There were some testing heavier loads but nothing ever worked real well. DaveinAZ had a blog on 20 ga nontox loading that has a lot of info if you can find it. A lot of those guys switched to TSS as it came available. I have made steel work and stick with the lighter payloads and just limit how far I shoot. 3/4 oz of #5,3, or 2 steel does all I need it to do to 35 yards. At the end of this past season I was shooting 130 and 150 gr of #5 steel through my 410 and took two full limits of divers with it.