I jumped into shotshell reloading last year on a whim and quickly realized it isn't as simple as brass rounds. I got some good info here, but started building a house before I got myself tuned in. I loaded up about 10 test rounds with Red Dot and never even shot them. With the house, moving in, setting up, winter, etc. I am just sitting back down to it.
Components were, and are a bit of an issue, but with a bunch of reading I think I have cross referenced diligently and have a safe starting point.
I have 2 3/4 Cheddite hulls, which by my understanding are compatible with Fiocchi, Rio, Nobel, Gold Medal, and Top Gun load data.
I have multiple primer options, but I have 1500 Cheddite 209 which I understand are almost directly interchangeable (verified by Alliant) with Win 209, CCI 209, and Rio 209. Green Dot -1/2 gr, Red dot minus a full grain according to thread comments..
I bought what wads were available before I realized they were load specific and then bought 12S0 for the Cheddite hulls. I have WAA12SL, WAA12, Figure 8, WAA12L, 12S0 and TGT12
I have Green Dot, Red Dot, Titegroup, and Unique. GD and RD are easy. It's the Unique load that is harder to find data for, and I want a load for unique because I have 4 lbs.
I found this load data on Castboolits..
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7/8 oz lee key drive slug filled with bore butter
fed top gun hull
cheddite 209 primer
CB fed 12s0 wad
23 grains unique
tested at 950 -980 fps
24.7 grains of unique
tested at 1213 fps
the same load with 20 grns of promo/red dot
tested 1141 fps
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I am mainly posting to make sure that my thinking is sound, but also being familiar with starting grains and max loads I am wondering how to work up a shotshell load. There is very little comparable data to extrapolate safe working loads with different components. I would like to start in a 'safe' range but I'm not sure if dropping powder charge too much has negative consequences.
Comparing with this load with reported light recoil also from castboolits..
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Federal Hull
22.9 grains Unique
Federal 12S3 wad (pink)
Hard wad (custom made)
1.3 cc COW I've searched, but I still don't know what this is!
Lee 7/8 oz Key Drive Slug (~370 grains)
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There is room for a spacer in the 12S0. I am thinking I'll use a Cheddite hull and Cheddite 209 primer, 12S0 wad, cardboard spacer, 7/8 slug and 22.5? starting grains of Unique.
Lyman's 5th has 25 gr of Unique in Gold Medal hulls with CCI209 primers and 12S4 wads at 1300 fps and 1080 psi. I have a chrono and will test velocities to gauge similarities before increasing powder charge.
What do you say, have I done enough homework to do this safely?
Any Load recommendations based on my components. I have 12S3 wads available and think I might order some. I saw some titewad but that is about all that's available for powder. I can't find Red or Green Dot anywhere.
Edit- I'll be shooting it out of a 590 Mossberg 3" chamber.