I have an ar pistol in 5.56 with sig brace, it's a 7.5" plus a kak flash can. While it's not bad, as far as blast and concussion to shooter, it's still noticeably louder then a 14.5-16" ar. Are bullpups with a 16" similar to the blast and concussion of a sbr/pistol ar15? Is the more blast/concussion due to the short distance of shooter to barrel end, or is it due more to the fact that powder is being burned outside of the short 7.5-10" barrel. Only been around one msar and it was 20" and several years ago. Thanks for any help.