Best way to sight in a Bushmaster M4A3??

[HawkTactical]

Hi, all.

I finally got to fire my M4A3 at the state game range this weekend. Like a fool, I forgot the front sight post adjusting tool. Now, it's been awhile since I had to qualify for Uncle Sam's Misguided Children, so, I was wondering if anyone had any good ideas as for the best way sight in my rifle. As it stands, once I adjusted the rear sight windage knob 3 clicks to the right, I was hitting center mass, but 6 inches high. Any idea as to how many clicks I should adjust the front sight post?

Thanks!!!

[DefensiveCarry.com]

[hogdaddy]

Can you lower the rear sites??

[A1C Lickey]

Six inches high at what distance? And if you don't have the official sight adjustment tool a bullet or nail works just fine.

[HawkTactical]

Six inches high at what distance? And if you don't have the official sight adjustment tool a bullet or nail works just fine.

6 in at 50 yds. Now I put the tool in my vertical foregrip, so I CAN'T forget it!

[matiki]

Over at ARFCOM:

RIBZ: Revised Improved Battlesight Zero

RIBZ - - Revised Improved Battlesight Zero (now with down-loadable 50 yard zeroing target) - AR15.COM

[Ram Rod]

You should follow the Bushmaster owner's manual for the initial sight in procedure. If I'm not mistaken, zeroing starts at the 25m range to hit point of aim at 300m and establish your battle zero. See pages 19-21 of the following pdf manual.
http://www.bushmaster.com/electronic...l/opmanual.pdf

[aus71383]

The 50 yard zero is also widely liked because it keeps you within 2-3 inches out to 250 yards. I believe the 36 yard zero is on target at 300 yard, but I think the elevation change is much greater using that zero.

On a 20" rifle the front sight post will move your point of impact 1.25" at 100 yards for each click (quarter turn). I don't recall what the elevation change is for a 14.5" barrel, but I'm sure you could Google that. Its probably 1.5" or so. I'd move it 8 clicks and see where that puts you. Remember where your front sight post has the arrow and says "UP" moving the post in that direction will move the impact of the bullet in the same direction - the FSP will actually be going down.

Austin

[matiki]

The 50 yard zero is also widely liked because it keeps you within 2-3 inches out to 250 yards. I believe the 36 yard zero is on target at 300 yard, but I think the elevation change is much greater using that zero.

On a 20" rifle the front sight post will move your point of impact 1.25" at 100 yards for each click (quarter turn). I don't recall what the elevation change is for a 14.5" barrel, but I'm sure you could Google that. Its probably 1.5" or so. I'd move it 8 clicks and see where that puts you. Remember where your front sight post has the arrow and says "UP" moving the post in that direction will move the impact of the bullet in the same direction - the FSP will actually be going down.

Austin

This is correct. With battlesight zero (50 yards) or improved battlesight zero (25 yards), and the appropriate adjustments to the rear sight drum, you have a very flat trajectory from 0-250 yards, and your adjustments on the rear elevation drum still work for longer shots. With military zero (300m) you have a much broader elevation spread at sub 300m distances.