20 inch 556 zero?

[Veshuma]

I'm familiar with a few for 16 inch. I like the 36 yard zero since I'm no badass. But would that 20 inch barrel really change it much? Make it shoot flatter? Input much appreciated.

 

[Catt57]

In theory the 20" will give slightly more velocity. This "might" equate to a slightly flatter trajectory.

Here, I found some charts.
https://www.everydaymarksman.co/equipment/barrel-length-trajectory/

No appreciable difference until you get to 150+ yards.

 

[conditionzero]

You will have a higher muzzle velocity and more energy down range than a 16". But if you are zeroing under 50 then it would not make a difference. At 100, you should have less drop than something flying slower.

 

[CAR-AR-M16]

Lots of good info here too:

RIBZ - - Revised Improved Battlesight Zero - AR15.COM

 

[KurtM]

Wow, that made my head hurt! Couple thing here, first off the 0-200 big aperture IS NOT any set MOA, grab a bunch of them and measure and you will find any where from same plane as the small aperture, to over 3 MOA difference, both up and down between the two. Next, if you re index the elevation drum the range lines will be off the amount you re index the drum, not suddenly be back on when you click it back up. And more to the point......

Zero your rifle for the range you expect to use it at. All these 36 yard/50 yard zeros are at best just a rough way to be on paper. Any mismeasurement up close will be WAY off out there! I couldn't even begin to tell you the amount of rifles I've seen that were zeroed with "fill in the blank" latest coolest 33 1/3 yard guaranteed be right on all the way out to 500 yards that couldn't hit a 10" plate at 200 yards. If you want a 200 yard zero, find a 200 yard range! For iron sight rifles I like a 300 yard zero, and I make sure of that zero on a 300 yard range.

 

[cowadle]

i agree. zero your rifle at what ever range you expect to use it. then also confirm how high the poi is at intermediate ranges like 50/100/150 etc to get your dope. it is also a good time to get windage dope also. for my use i use a 200 yard zero but i get the dope out to 600 if i can so i can adjust for hold over if i want to.

 

[JEVapa]

Hmm

 

[wolfkpr]

Im a fan of “ zero at 50= +2”@100..” as it put me on point at close “ in the woods” ranges, about + 2” at 100.. and basically within 2” either way out to 230 ish

 

[conditionzero]

i agree. zero your rifle at what ever range you expect to use it. then also confirm how high the poi is at intermediate ranges like 50/100/150 etc to get your dope. it is also a good time to get windage dope also. for my use i use a 200 yard zero but i get the dope out to 600 if i can so i can adjust for hold over if i want to.

I think this is key. There may be some "one size for all" zero's and they work OK. But if you have a use case, you should set up your tools for it. As in, if you are shooting long range at 50 yard zero makes little sense. Conversely if you are only shooting out to 100 with the majority inside that, a 50 might be perfect.

 

[madokie]

i always have my 5 shot group centered about 2 inches above the point of aim at 100yards,, that way u aim 8 inches above the belt buckle and the bullet will hit anywhere from just above belt buckle to just below the neck,0-300yards..this type of zero works on most any centerfire bottleneck cartridge.