Sighting in an AR with .223 or 5.56, difference?

[jd4320t]

I bet when they switch production over from m193 federal to .223 American eagle at the factory its a matter of switching the packaging.
I am also willing to bet the cases are the same dimensional sans headstamp.

This 5.56 vs .223 argument is silly. Someone please post a link or proof of 5.56mm damaging a .223 rifle.

The 556 has more recoil than the 223. I guarantee that. I'd only shot 223 for a while and then got some 556 and noticed it right away.

 

[sporter]

The 556 has more recoil than the 223. I guarantee that. I'd only shot 223 for a while and then got some 556 and noticed it right away.

Did you ever consider that many civilian branded ammo is underpowered no matter what the caliber. Basically the mfgs get to save a bit since they don't have to meet a mil contract spec.

Kind of like le rated ammo vs wally world loadings.

 

[Charlie2]

WOW...?????

 

[Solidgun]

There are differences and if you don't know or don't want to read more about it, stick to the caliber noted on your firearm (or uppers).

 

[Twisterx44]

Time to look up some SAAMI specs, eh?

 

[Mordred]

Kart29's got the right answer.

 

[Wild Deuce]

I don't know about all the technical specs and I don't own a chronograph. What I do know is that a couple years ago when I was shooting 55 grain 5.56 NATO and 55 grain .223 REM (from the same manufacturer ... I think it was Winchester) out of the same rifle/day/conditions/etc., there was a measurable shift (not huge but still measurable) in the groups (both in size and point of impact). That was at 100 yards if I recall correctly.

 

[sloughfoot]

I own a chrongraph and a 20 in AR with a military chrome lined barrel 1X7 twist with a 5.56 chamber. I own plenty of mil-spec M193 55 grain FMJ ball ammo and Remington commercial 55 grain FMJ ball ammo.

I also have lots of NATO M855 62 grain ammo and lots of 75 grain reloads that are supposed to be runnig about 2750 fps. Problem is, I don't have a rifle with a true .223 chamber. My other 20 inch AR has a RRA Wilson barrel which has a Wylde chamber.

To answer the previous question about pressure, even though I don't know the precise pressure a given load generates, the higher the pressure, the faster the speed. As long as the bullet is traveling at the proper speed, the pressure is within limits. Of course, we already know that the proper powder is being used

There are no matches at FWRR this Saturday. Anybody want to meet me there to chronograph bunches of loads? Of course, somebody with a 223 chambered rifle would be really welcomed.....

 

[U.S. Patriot]

At 100 yards, I have seen no difference between .223 and 5.56 55 grain rounds in terms of POI. It's probably you, sounds like you need to work on the basics of marksmanship.

 

[Charlie2]

If you have two different kinds / types of ammo, I would think you would have two different POI..!!??? Yes / No ..???

 

[RichardR]

It doesn't just happen when switching from one brand or type to another, variations can occur in one batch/lot to another as well.

So even if your shooting the exact same ammunition as you've always shot, a different lot # could = POA/POI variation, simply due to variances in manufacturing.

Also changes in temperature, humidity, barometric pressure etc can all effect POA/POI.

 

[Charlie2]

Exactly ..!!!!! What he said..^^^^^^^^

 

[Wild Deuce]

... It's probably you, sounds like you need to work on the basics of marksmanship.

* Changed my mind. Not worth a response.

 

[U.S. Patriot]

Coming from a Coastie to a Jarhead ... that's what I call internet bravado. That's funny.

Just calling it from my experience. I have shot with friends that have had the same problem. Some rounds would impact center of target, and they would throw some. Regardless of ammo used, or caliber. That's why I would make sure it was the shooter, before I assumed it was the ammo. Take away any human error. Me being a Coastie and him being a Marine has nothing to do with it. You do not have to be a Marine to be a good shot. That's just assumed stupidity!

 

[Wild Deuce]

Just calling it from my experience. I have shot with friends that have had the same problem. Some rounds would impact center of target, and they would throw some. Regardless of ammo used, or caliber. That's why I would make sure it was the shooter, before I assumed it was the ammo. Take away any human error. Me being a Coastie and him being a Marine has nothing to do with it. You do not have to be a Marine to be a good shot. That's just assumed stupidity!

I'm the idiot. I ASSUMED you were talking to me in reference to my previous post ... not the OP. I would like to think that I have a pretty good grasp of basic marksmanship after 8 years in the Marine Corps so I was too quick to take it personally.

Either way, I stand by my observed POI shifts and group spread increases since they occured from a bench rest as well as prone. Who knows ... maybe I don't know what I'm doing.

 

[U.S. Patriot]

I'm the idiot. I ASSUMED you were talking to me in reference to my previous post ... not the OP. I would like to think that I have a pretty good grasp of basic marksmanship after 8 years in the Marine Corps so I was too quick to take it personally.

Either way, I stand by my observed POI shifts and group spread increases since they occured from a bench rest as well as prone. Who knows ... maybe I don't know what I'm doing.

I have seen people throw rounds even shooting from a rest. If you change your cheek weld, change the postition of your trigger finger, or even jerk the trigger. Rest or not, you are going to pull shots. I just helped a friend that was having that issue. At 50 yards shooting off a rest, he was still pulling rounds. I tried his M4, and I was hitting dead center. I'm not saying I'm the best shot. I had him work on trigger control, and by the end of the day, he was starting to produce some decent groups. I see bad mechanics all the time at the range.

 

[9mmfan]

 

[thompal]

It doesn't just happen when switching from one brand or type to another, variations can occur in one batch/lot to another as well.

So even if your shooting the exact same ammunition as you've always shot, a different lot # could = POA/POI variation, simply due to variances in manufacturing.

Also changes in temperature, humidity, barometric pressure etc can all effect POA/POI.

I can see how variations in the ammo can cause POI changes up or down, as bullet weight, BC, and velocity changes affect the amount of drop. I can also understand a group opening up as a result of changes in ammo, but I don't understand how changing ammo can move the POI right or left.

 

[Kart29]

I can see how variations in the ammo can cause POI changes up or down, as bullet weight, BC, and velocity changes affect the amount of drop. I can also understand a group opening up as a result of changes in ammo, but I don't understand how changing ammo can move the POI right or left.

I don't understand it all either. But, I've witnessed it many times.

I am constantly experimenting with different powders, bullets, amounts of powder, COAL, bullet runout, primers... you name it. It is not at all unusual to find that one bullet will hit left or right of where a different bullet hits - even bullets of the same weight and general construction. For example a 40 grain SP made by Hornady might hit several inches left or right from where a 40 gr. SP from Sierra hits. I don't usually see much difference in windage when merely adjusting powder charges but will definitely see an immediate elevation difference.

When talking about 55000 psi pressure, changing temps, and minutes of angle variation, a steel gun barrel is about as stiff as a soggy noodle. Any little change in the ammuntion could easily have caused the shift in impact shown on that target. There are internal stresses in the steel of the barrel, the way the barrel is held in the stock or to the receiver. It's all a mix of offsetting forces that cause a barrel to react a certain way when the powder burns. Just changing the shape of a bullet may change the bearing surface length between bullet and barrel thereby altering the exact position of the bullet at the point of peak pressure from the powder charge. Changing this point of peak pressure might make the barrel flex just a little bit differently than it does with the other bullet. I don't know exactly what all the causes are. But I know a barrel bends and whips around all over the place while the bullet is traveling down the bore.

 

[Goober135]

Getting a little better after day 2 (only shot .223 though)

10rds @ 100yds