Long shot is an excellent powder in that it will allow high velocity with lower pressure.
My finding are it does not like the low end of the scale if a clean burn and no soot on the cases is what you want.
That said your loads were to light, plain and simple, not unsafe, just not the best and that is evident from what you have seen. Hodgons list 6 grains as a start load and 6.8 as a max with 16,800 as a CUP.
and 875 for the speed, 875 is somewhat over standard military ball ammo.
I use 6.5 of long shot and it's a clean burn but a little snappy for extended shooting at close range for just paper targets. Tight group and bulls eye are much better if you just want a target load, I understand that powders are a little difficult to come by now.
As for crimp ? my finding are it depends a lot on neck tension, with crimp being about 10% of bullet hold.
Then again Alloy must be look at, a soft allow will suffer as to the bullet being reduced when seated with to small an expander, and a hard allow will not have enough hold with a big expander.
Enter the delicate balance. The crimp on a 45 ACP should not be much more that what is needed to remove the case flare, yes sometimes a little more is needed for rounds to function in certain pistols allowing for barrel and feed ramp tolerances.
Short answer: bump up your load, don't go over max and don't over do the crimp.