5744 and oatmeal, organic or otherwise? I predict no change to the brass and a very dirty barrel and, when you pull the brass out, a chamber full of powder kernels. Of course, when the oatmeal finally makes a plug in the barrel you could be looking at a ring. I wouldn't do it. Don't try to reinvent the wheel. 10 grains or so of a fast pistol or shotgun powder and COW - Cream of Wheat (or, but hard to find in New Jersey, grits - but they stink!).

Guarantee to work perfect
This is what I do, 38/50 rem 303 brass and numerous others. 
1 Anneal brass 
Pistol primers
Sm charge 10-15 hrs start low, Fast or fastest pistol powder, cover with cream o wheat, corn meal,  etc, Some say corn wears bore... I’ve not seen, but won’t say it can’t. Tuft of paper cotton to cap, not needed if you keep it upright. 
Shoot it,
Trim,
Ready for paper patch loads, resize for others 
Done

Annealed all 200 cases, so that's out of the way. Trimmed 50 to length (based on a chamber cast). Loaded a couple with 18gr of 5744 and oatmeal before deciding that was about as much trouble as loading with a bullet, so loaded the balance with a normal load and a bullet and will 'fire for effect'. 

BTW - I use a case-forming expander die that Chris gave me several years ago to make 30-40 Gov't cases into 38-50 cases. As Chris mentions, anneal and then a bit of case lube inside & out on the case mouth (about every 5th case) and it is a one-step process.