In my experience, using mixed 45 ACP brass, one headstamp will often weigh more or less than another headstamp. Sometimes weights with the same headstamp will vary as much as 8-10 grains.
I use Titegroup and PowerPistol in 45 ACP. Both (based upon published data) utilize a smaller powder weight than common/probable case weight variation.
Pull the bullets and start over, or, shoot slowly being very careful of a squib..
Just my .02 cents