So got to the range with some 225gr LFP over 6.1gr of Herco. The stuff I shot is approximately 33 years old. However it's been stored in its original container in a room that averages between 45 and 65 degrees year round, and looked/smelled completely normal. One gun was a gen 1 M&P .45, 4.5" bbl. The other was a Ruger 1911CMD 4.25" bbl.
One anomaly I experienced was velocity of the first shot from a clean bore was very low compared to the remainder of the 7 shot string. I can only guess a clean bore provides less resistance and less opportunity for gas pressure to build behind the bullet (if not that, I'm not sure). After that fouling shot, velocities settled into a nice, stable pattern.
Herco is rated as a somewhat slow-ish powder, a little slower than Unique per research. Alliant uses a max load of 6.4gr under a 230gr LRN, but no starting load, so I settled for 6.1gr under the 225gr LFP I was using.
My Ruger 1911CMD averaged 813 fps, SD 27. High - 857, Low - 779 (first shot).
S&W M&P 1.0 averaged 829 fps, SD 23. High - 869, Low - 788 (first shot).
Recoil and ejection pattern felt like any other standard pressure service load, believe I'll leave it that for the remainder of this can. Hope everyone that wants to has a chance to get some lead downrange this fine day.