I don't know how many Db the change would be but all the bull-pups I have fired have sounded louder as the chamber is closer to the ear. As far as a two stage trigger, the trigger bar will have to be magic as the biggest problem with bull pups is the long reach from trigger to sear. usually gets junk in them and flexes as it gets more and more grime in the mechanism.
Know it is not a sniper rifle but even the battle rifles that I have played with have suffered some as a bull pup ergonomically. As far as accurate out to a couple of hundred yards, daaaammmmmm, most guys can do that with an M4 offhand.
Oh well, I look at it as another toy to play with.
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Hold Hard guys
Rick B.
Knowledge is knowing a tomato is a fruit.
Wisdom is knowing it is great on a hamburger but not so great sticking one up your ass.
Author - Richard.
Experience is what you get right after you need it.
Author unknown.