.223 VS 5.56 Sight In

[Will]

Wondering how much  point of impact changes at say 75 yards with the same 55 gr bullet.  AR 16: BBL   Anyone ever compared the two?

[TGO David]

How much precision do you need?  The variance is not going to be all that great for most purposes, but POA and POI will always shift any time you change between ammo make, variety, grain weight, etc.

It's probably more important to determine what grain projectile performs best for your rifle's barrel twist rate.  Then take the practical approach and shoot both .223 and 5.56 with that grain (or as close to it as possible) at varying distances and see how the POA/POI shifts.  If the variance tracks fairly linearly, divide the difference in half and set your optic there right in the middle between them.

 

 

[Omega]

While I understand there is a difference, I haven't noticed any practical difference between the two, I sometimes suspect there is none, just packaging. 

[Raoul]

2 hours ago, Will said:

Wondering how much  point of impact changes at say 75 yards with the same 55 gr bullet.  AR 16: BBL   Anyone ever compared the two?

I'm not quite sure what you're asking.

[Will]

Not critical.Sighted in .223 55gr 16" BBL 1/7    and next is 5.56/55gr and wondering how close group should be Something to gauge group by..

[Omega]

3 minutes ago, Raoul said:

I'm not quite sure what you're asking.

Commercial .223 vs surplus 5.56 ammo in the same weight.  Any POI or POA changes vs the two.  

[Raoul]

Well my take on it is that I don't notice that much difference. But...there are so many variables involved that I truly believe that some guns do have a favorite ammo. The only way to be definitve is to spend the time reloading and come up with a load for each gun you shoot. But who has the time for that?

 

[TGO David]

7 hours ago, Raoul said:

Well my take on it is that I don't notice that much difference. But...there are so many variables involved that I truly believe that some guns do have a favorite ammo. The only way to be definitve is to spend the time reloading and come up with a load for each gun you shoot. But who has the time for that?

 

Yeah. It’s still important to understand what the intended use is and at what distance. 

Bullseye shooting? Defensive use?  Precision marksmanship in an LE or MIL setting? Hunting?

There won’t be enough difference to care with some of those applications. For others I’d want to know which round performs best with my particular rifle and then stick with it. 

[gregintenn]

Shoot em and see.

[TGO David]

8 hours ago, Raoul said:

 But who has the time for that?

 

Ain't nobody.

[Will]

One more question on this.  At 75 yds   72 Gr VS 55 Gr   Higher lower?   It will be for a NC Hog Hunt 100 yds max   Not bullseye match but still important.

[Will]

And I will be sighting in both weights in future.just wondering what to expect.

[Omega]

2 minutes ago, Will said:

One more question on this.  At 75 yds   72 Gr VS 55 Gr   Higher lower?   It will be for a NC Hog Hunt 100 yds max   Not bullseye match but still important.

You don't have another caliber?  If not, or you just want to use your AR, then I would probably go with the heavier bullet, but make sure you have a fast twist, like 1:7 or maybe 1:8, anything slower may not stabilize the bullet enough.

[Will]

Have no other caliber,but would still use this. Most of the group use AR .223 72 gr  and a few .308 Cal   It is all about shot placement and quick follow up if needed. A proper placed shot with a .223 will kill a hog as fast as a 300 Mag.

[chances R]

i've seen a boar as big as a volkswagon......that 308 would feel better to me.

[Garufa]

34 minutes ago, chances R said:

i've seen a boar as big as a volkswagon......that 308 would feel better to me.

A hog needs to be properly thumped.  .308 might be a good start.

[TN Song Dog]

Pick the one load you plan to hunt with and then go sight it in. I would pick the heavier weight bullet. Wouldn't advise ever changing ammo to hunt without re-verivying zero. Can't assume it will be high or low based on bullet weight. Doesnt exactly work like like that. May be either high or low... and may also be right or left. Could be dead on still at 100yd... just cant say. Every rifle behaves differently even with same ammo. Wish there was another way, but just gotta physically shoot each and sight in. Good luck

Edited October 24, 2020 by TN Song Dog

[ReeferMac]

Agree with the finicky rifle idea.

I couldn't find a good setting on my scope b/c I kept trying different ammo (5.56 and .223). Finally started noticing I had consistent groups with one particular brand/weight). Thats all I buy now, by the case, and my scope is perfect. For BEST results, find what your rifle likes, and persue that. For quick and dirty setup for multiple brands, I'd say you're on the right track, group by weight, split the difference.

[chances R]

true for all rifles IMO.  buy several different brands and wts.  Shoot 3 -5 shots not worrying about POI.  Once you find the best group, then zero the scope and for precision shooting stock up on that particular brand, wt, and lot number.