Ok, top row, with that 1 nickel Winchester brass, s 24.0 grains of Accurate 2230. This is 55 grain FMJ 2.250 max charge for basically 56k PSI would be around 25.5 grains, bceause of the super long OAL. With 2.200 it would be 24.9. The following are general estimates, using various methods, such as one popular pressure calculator.
24.0 AA2230 ~51k PSI Super flat primer. Cratered.
23.5 AA2230 ~48k PSI Super flat primer. Cratered.
23.0 AA2230 ~44k PSI Super flat primer. Cratered.
22.5 AA2230 ~41k PSI Less flat primer. No crater
22.0 AA2230 ~38k PSI Slightly flat primer. No crater
21.5 AA2230 ~35k PSI Rounded primer, normal looking firing pin strikes
All loads, easily cycled a "non adjustable, normally gassed" direct gas impingement 20" AR15.
And the 21.5 shot soft, low recoil.
If Pistol primers were all I had? I would use them in my rifles, without even hesitating, and load them to estimated 35k pressure, like above 21.5 Grain AA2230 load.
That doesn't mean we are telling YOU to do it. Do not do what we do. Consult your powder choice manufacturer first, to understand their recommended minimum. I would recommend Shooters World Tactical rifle powder, which is designed for this, as it can go as low as ~18 grains and still cycle most AR's.