Welcome to the Asylum. You seem to be learning from your mistakes... very good. It's the hard way, but you never forget it.
Before I start prepping for my 2nd run I had a few questions.
1) Is it necessary to crimp these rounds? - the two die Hornady set I have, does not crimp
2) What length should the .223 cases be trimmed to?
3) In what instance would one use primer sealer, instead of just seating the primer in without it?
4) Is there a difference in a 223 casing and a 556 casing?
How is your barrel marked... .223 Rem or 5.56 NATO (Or, .223 Wylde)?
1. Yes, unless you are firing them singly, as one might with long seated bullets just off the lands, (not from the magazine) you want a taper crimp to hold the bullet firmly in the case.
2. 1.760" is the SAAMI max. case length. See here
3. Only for long term storage or extended extreme wet conditions.
4. Yes and no. The .223 Rem & 5.56 NATO are externally the same, occasionally give or take a few thousands in non-critical areas. The primary difference is brass thickness... the 5.56 NATO brass being thicker than .223 and for a given powder charge, you will have higher pressures. Refer to you're reloading manual.
5.56 NATO brass also has a crimped primer pocket and must be swagged or reamed to fit a new primer.
Also... When I knocked the stuck rounds out of my barrel, the few taps that I gave them, pressed the bullet head inside the casing. I just don't get the feeling that I am doing this right because I can't image the bullet should go inside the casing that easily.
See response #1.