I've used it in 45acp.
The problem I had was it was prone to squibs in cold weather. I was using standard primers, magnum might have worked better. Ran fine in warm weather. I wouldn't recommend it for 45acp unless it was all you had.
I never used it in shotgun.
"Pressure spikes" is a bullshit term tossed around by mental midgets who don't understand what "max load" means in their reloading data.
