Hi everyone first time poster so go easy one me. My question for you all is, does excessive headspace cause a slower muzzle velocity? Yesterday I went out to do some shooing at 700 yards. Using the same amount of elevation I always use I shot about three rounds at some steel. I noticed that the rounds were hitting about 7-10 inches low. I didn't give it much thought just dialed up some more elevation and started shooting again. Used this new dope for the rest of the time and was on target. Later that night I was cleaning up my brass and noticed that almost all of them had signs of thin wall around the case head. Brass had only been reloaded twice before. Checked some of the rounds that I had not shot yet with a hornady headspace gauge and notice the shoulders had been pushed back to far and causing to much headspace. Unfired brass was a little over 0.010" shorter than the fire cases. I reset my sizing die to fixed this issue. Anyway I got to thinking and was wonder if the excessive headspace caused my rounds to go low. I was thinking that since the brass and to expand more to fill the chamber that it would cause a loss in pressure resulting in a slower muzzle velocity. Am I thinking straight or just making excuses? Thanks.