Implications of a shorter front sight

[barrysuperhawk]

Hey guys, I have a 20" DPMS Classic .308 and I decided I wanted to replace the monstrously thick front sight with a skinnier one to allow for more precision. I noticed it looked rather tall, so when I had the option of what front sight post to order, I ordered the longer of the 2 choices. When the sight post arrived and I installed it, I noticed that even the longer of the 2 options was shorter than I was removing. I went ahead and installed it but I didn't like how far up it was sticking [the original was above the ears on the FSB] and I also did not like seeing daylight under the base of the front sight post or the tenuous detent positioning, so I went ahead and screwed it in to a more proper mounting depth, and now I have to work out where to aim, etc.

Logically, I should be able to aim low [6 oclock hold] on close targets and be able to dead hold on farther targets without having to adjust my rear sight, but I don't know how close this is going to be in reality, and events have conspired to keep me from going to the range to positively verify any of my assumptions, so I figured I can't have been the first to have ever had this problem, so here I am. I remember hearing service rifle shooters talk about filing their front sight down to allow a 6oclock hold when it was already bottomed out, but I confess I didn't pay much attention at the time.

Right now my load is a 155gr Amax at 2800fps. My targets are 90% going to be the MGM flashers out to 5-600 and those skinny little mini-poppers out to maybe half that. I would like some guidance and guestimation on my holds, sight picture and trajectory so when I do make it to the range I am at least on paper and don't look like a total douche.