View Full Version : Whats the difference? 55 gr 223 vs 62 gr 5.56

09-25-2010, 1:55 PM
Has any of you guys shot a variety of ammos and noted the difference in performance?
I have a scope that is BDC calibrated using M855 62 grain ammos.
As per the instruction, it can be zeroed at 25 yards using the 300 yard dot. Once zeroed, you can move the target at 100 yard and just fine tune your zero. When this is achieve, you can have accurate head shots up to 300 yards and body shot up to 600 yards without making any adjustments on the scope dials.

I only have 223 caliber 55 grain ammos, and used it to zero the scope. After getting it zeroed at 25 yards, moving to 100 yard and firing 10 shots, all shots were like 3 - 5" high. If I make any elevation adjustments to get it zeroed at 100, I'm afraid that I'll be off mark on the 25/300 yard distance.

So, that being said, does the 55 grain 223 ammo really has that big of a difference with a 62 grain in 5.56?

While I'm at it, is there also a big difference between a 77 grain Sierra Matchking HP in 223 compared with a 77 grain OTM in 5.56?
I read that 77 grains is the optimum round for the 1/7 twist barrels, but between the two types, the 223 round is cheaper.

09-25-2010, 4:15 PM
About 7 grains.

Seriously, yes different ammo weights will have different point of impact. If you primarily shoot 55gr, then zero it for that ammo and check your hold-overs at the various distances-like you need to do anyway to confirm them. Do not rely on the users manual to magically get you hits out to 600 yds without testing the setup with you pulling the trigger.

09-25-2010, 4:21 PM
^^^ With him. Its pretty self explanatory. What is the difference between a $1.00 and $0.50..Just messin with ya

09-25-2010, 4:25 PM
Must be the Nikon offering.........