1. You saying you use FMJ for carry/home defense? Just curious as that is how your post sounds to me. If so I just caution against the use of cheaper ammo for that purpose. Both because of performance and because of quality issues that might arise that are somewhat mitigated with more expensive ammo.
2. How many times had that round been re-chambered? I tend to shoot off the chambered round every month just to be on the safe side (use one round for chambering that month, shoot it beginning of next at the range). The difference is sometimes noticeable, though nothing near that.
What you're seeing is called setback. It can and does happen. It's something that needs to be watched for. Some cartridges will have a strong cannelure in an effort to prevent this.
Know the status of your weapon
Keep your muzzle oriented so that no one will be hurt if the firearm discharges
Keep your finger off the trigger until you have an adequate sight picture
Maintain situational awareness
Last edited by TunnelRat; October 5, 2012 at 02:25 PM.