What is the Ideal yards to zero my M4

[daveholl]

Now that I have completed my M4 build its time to zero the shotguns sights ( ghost ring and Aimpoint ).

The effective range of a slug is much further then the lets say 00 buck shot or #4 buck 

The M4 being what it is , at what distance should I zero in my Ghost rings and red dot 

Also my assumption is I should zero the gun using slugs ?

 

[Pack Rat]

Zero for whatever range you’re likely to need it most.

[StrangerDanger]

Realize nearly every different brand and type of shell will pattern differently.
 

What I do is sight the shotgun in at 70 yards with slugs. I then pattern the shotgun at much closer ranges with various buck/bird shot to see how the pattern is and how it correlates with the sights/optic. Usually the parallax is so minimal and the fact that you have multiple spreading projectiles, you can’t tell the difference. Buck and bird are going to be a single rathole 5 yards and in. As you get farther, your pattern will change based on your barrel, choke choice, ammunition and so on. So you’ll need to pattern the specific round to have a good idea of how it’ll perform at various ranges. Using FlightControl rounds will almost always perform better than shells without. At that 70 yard mark, your B27 will likely have multiple hits in the body of the target. Several will likely be off paper. If three pellets out of nine-twelve hits an assailant at 70 yards, they’re going to have a bad day. Especially with your fast firing auto loader that you’ll likely be sending multiple rounds down range at them until they hit the dirt and stop doing the curly shuffle. 

 

Be aware of the parallax when firing at extremely close ranges. Your optics/irons sit above the bore. So, if you’re at point blank muzzle contact range, your Point of Impact is going to be roughly an inch below your point of aim. 

[Unobtanium]

I zero at 50 yards using slug. I do not believe that a 50, 25, or 100 yard zero would impact the kind of thing a shotgun is likely to be used for when it comes to violence, unless you are hunting, and then your hunting AO will dictate distance so you wouldn't be asking. (Yes, I have work to do)

 

 

[radar x50]

On page 65 of the USMC TM 10698A-10/1 it states "it is recommended that the iron sights of the combat shotgun be zeroed at a range of 100 meters with a single projectile (slug) ammunition and 25 meters using multiple projectile (00 or 000 buckshot, etc.).  It is also recommended that three-round groups be fired prior to making adjustments when zeroing with slugs.”

[M2_shootr]

I sight in at 25