Lemme grab my notes....
20 ga low recoil :
12.5gr / .095 bushing Unique
CCI Primer
WAA20 Wad
RP Hull
Used 1/2 oz of shot, or 5 count of #1 buck. Notes say that it wouldn't cycle my buddies semi auto, "but made him grin in the side-by side was like shooting a .22"
Thats for my buddy who only has one good hand to grip the gun with, so actual recoil is particularly important for him. Ya, I'm wiling to go "outside of the box" to get a handicapped friend out shooting more- feel free to stick that right in your "exact recipe" pipe and light it right on up. He joins me every time he can now, and has worked up to bigger rounds. We've gone through about 3 or 400 hundred of those 5 ball #1 loads. He's gotten to the point where he can take short clays with them
We eventually got the gas gun running using HS-6, but you wanted lowest recoil.
There ya go.
IF you use the Lee powder charge table, the loads tend to be on the milder side.
I'll provide it for you here :
http://www.leeprecision.com/cgi-data/instruct/LA1071.pdf
That load data really sucks for slugs. Its really good for shot columns.
So if I wanted to make some low recoil 20 gauge 2-3/4" 3/4 oz #4 buckshot what kind of powder should I use and how much?
I don't use #4 , so I couldn't testify first hand. I would use a 7/8th oz load recipe in a trap wad, and load without overloading which will cause the case to buckle, or crappy crimps, or both. Weigh out #4 buck ( think its 27 pellets to the ounce ? ) - so you are looking at around 23 pellets, and find something that stacks right in the wad. a 3x3 pattern will net you 24 pellets, so thats gonna be a tricky stack, I can tell already. I wouldn't be afraid to use 24 if it stacked well, and crimped well. COnversely, I would be ok if I needed to use 21 and some buffer to get the crimp right.
When doing load workup, even using TP to help get the crimp right until you know what it needs to be can be really helpful- it was to me. Do yourself a favor- take a 20 ga hull, and glue a wad in it over the powder charge ( no new primer- this is just for stacking practice ) to make a "dummy" . You can try different loads stackin' in without the wad jumping around when you take the balls in and out.
After I made 5 or 6 of these to practice different kinds of shot/wads in 12 ga- I made one for 20ga, and .410, too.
You wont get a lot of help in "experimental" shotgun loads here at THR.
Apparently you WILL put your eye out. And thats sound advice- you should load carefully. You are trying to do something outside the box, so keep that in mind. When you go outside of published data into substitutions, it can get a little dicey- I know, firsthand. You've only got about a 6k psi window of operation, so please, load carefully.
I recommend the Lyman shotshell reloading book- it has a lot of info for 20 ga.
You can buy it here :
http://www.midwayusa.com/product/88...loading-handbook-5th-edition-reloading-manual