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View Full Version : 5.56 vs .223 accuracy


hkwinger
04-17-2012, 2:20 PM
Hey guys,

Just got back from the range and I had a few observations/questions. I am using a colt 6720 upper (H bar 1/9 16 inch). It is about 5 years old with a round count about 2000. I almost always shoot 55 grain fmj (winchester white box/federal mostly) I had it sighted in on my ACOG and I was shooting at 50 yards to sight in my new RMR. I was getting about an inch to 2 inch groups (I am not great) but consistent. I was able to pick up lake city 5.56 (62 Grain steel core) but have never really shot a lot of it because ranges usually don't allow it. I noticed my hits were 2 inches low and 2 inches to the right. Same tight groups but consistently off target. I switched back to the 55 grain and bam, right on target. I even ran some tull and that was about 1 inch low and 1 inch to the right (55 grain as well).

Is this normal? Has anyone experienced the same results. I know ammo is different and weights are different, but 2 inches off at 50 could be a big problem at 100 yards. I didn't try it today, but I would guess maybe even 6-8+ inch variances, and that could be an issue. What ammo do you guys use to sight in with? I decided to just try a bunch of different ammo because I am probably watching too much of the prepper stuff on TV and wanted to test different stuff through the rifle. I am wondering if its .223 vs 5.56.

Thanks in advance for the advice!

Chaos47
04-17-2012, 2:26 PM
You know that you are shooting 2 different brands and different weights but you automatically disregard that and start another 5.56 vs .223 thread that will just turn into a war?

You can not test 5.56 vs .223 without using the same grain at least.
Your scope is zero'd for the lighter ammo. Of course the heavier will impact lower.

Paper Boy
04-17-2012, 2:33 PM
I sight in with the ammo I will be shooting.... Why would you sight in with 55 Grain only to switch to 62 Grain?

You said they all grouped the same and there is your answer. A point of impact shift using different weight ammo, or even just a different kind of ammo, does not mean its less accurate....

My bolt action .223 with 55G hand loads hits higher then off the shelf 55G ammo because it is much hotter. Still is a tack driver just has a different point of impact because of the ballistics.

glock 357
04-17-2012, 2:35 PM
The only diffrence is thicker/thinner brass, possibly steel penetrating / possibly for varmit hunting / possibly plinking, more/less powder etc. One being military the other commercial should be simple to google or wiki the two to understand.

One inch to the right can be either your trigger pull, your sight is out of alignment, your cheek is not rested the same as the last run, etc. Wind can be a factor as well.

With both cartridges I shoot 1.5" from a carbine -1" with a 20" AR without sight adjustment for any ammo> If its lighter or higher grain it's eith up or down from where I'm aiming at. The barrel doesn't move but your position does.

Chaos47
04-17-2012, 2:37 PM
http://www.butlercc.edu/engineering/en115/Parts/accuracy_precision.GIF

killshot44
04-17-2012, 2:37 PM
Is this normal?Yes
What ammo do you guys use to sight in with?
The same ammo I'll be using
I decided to just try a bunch of different ammo because I am probably watching too much of the prepper stuff on TV
Stop doing that
I am wondering if its .223 vs 5.56.
No, it is not.

As Chaos says, you're comparing apples to tangerines. Every type you used has a different weight and velocity.
If you don't expect a 16" HBAR to shoot MOA you'll have a happier life at the range.

mif_slim
04-17-2012, 2:38 PM
You know that you are shooting 2 different brands and different weights but you automatically disregard that and start another 5.56 vs .223 thread that will just turn into a war?

You can not test 5.56 vs .223 without using the same grain at least.
Your scope is zero'd for the lighter ammo. Of course the heavier will impact lower.

I sight in with the ammo I will be shooting.... Why would you sight in with 55 Grain only to switch to 62 Grain?

You said they all grouped the same and there is your answer. A point of impact shift using different weight ammo, or even just a diffrent kind of ammo, does not mean its less accurate....

Now now guys, calm down, he's asking a simply question...no need to get all :mad: about it.

Hey guys,

Just got back from the range and I had a few observations/questions. I am using a colt 6720 upper (H bar 1/9 16 inch). It is about 5 years old with a round count about 2000. I almost always shoot 55 grain fmj (winchester white box/federal mostly) I had it sighted in on my ACOG and I was shooting at 50 yards to sight in my new RMR. I was getting about an inch to 2 inch groups (I am not great) but consistent. I was able to pick up lake city 5.56 (62 Grain steel core) but have never really shot a lot of it because ranges usually don't allow it. I noticed my hits were 2 inches low and 2 inches to the right. Same tight groups but consistently off target. I switched back to the 55 grain and bam, right on target. I even ran some tull and that was about 1 inch low and 1 inch to the right (55 grain as well).

Is this normal? Has anyone experienced the same results. I know ammo is different and weights are different, but 2 inches off at 50 could be a big problem at 100 yards. I didn't try it today, but I would guess maybe even 6-8+ inch variances, and that could be an issue. What ammo do you guys use to sight in with? I decided to just try a bunch of different ammo because I am probably watching too much of the prepper stuff on TV and wanted to test different stuff through the rifle. I am wondering if its .223 vs 5.56.

Thanks in advance for the advice!

The problem you have is, like mention above, different ammo. Different ammo can change a lot and some will shoot just the same. You never know, that is why you choose what you want and think is accurate and buy them in bulk. Even batches of the same brand but made one day after another can very.

This is what most precision shooters load their own ammo to get the same consistency over and over.

Paper Boy
04-17-2012, 2:41 PM
Now now guys, calm down, he's asking a simply question...no need to get all :mad: about it.

Did not mean for it to come across as :mad:. Was asking a real question - why would you sight in with one if your planning to shoot another? Is there a reason? One round for the range where you have to shoot non steel core, and one for BLM fun? Some other reason?

mif_slim
04-17-2012, 2:47 PM
Did not mean for it to come across as :mad:. Was asking a real question - why would you sight in with one if your planning to shoot another? Is there a reason? One round for the range where you have to shoot non steel core, and one for BLM fun? Some other reason?

Maybe he's just learning. Its a learning experience for him. :D

hkwinger
04-17-2012, 2:48 PM
Did not mean for it to come across as :mad:. Was asking a real question - why would you sight in with one if your planning to shoot another? Is there a reason? One round for the range where you have to shoot non steel core, and one for BLM fun? Some other reason?

Guys,

No worries. I guess I should have explained it better. This is my "oh crap" rifle. I am not a marksman. I wanted to make sure it fed all different kinds of ammo just incase the one in a million chance I would actually need it (hunting/protection or anything like that). I was just wondering if there was some sort of middle ground. The thought that crossed my mind "man if I switched ammo's, I would have not even been able to hit a deer sized target at 100 yards, is this normal". Thats why I asked.

Thanks again.

Bhobbs
04-17-2012, 2:52 PM
Ammo in different weights, different brands and even different lots of the same brand will shoot slightly differently. It's all about variations that are going to be present no matter how expensive the ammo.

Chaos47
04-17-2012, 3:00 PM
Now now guys, calm down, he's asking a simply question...no need to get all :mad: about it.

Sorry that I sound " all :mad: " about it but it is silly to have facts and disregard them for an assumption.

Fact two different brands of ammo where used
Fact two different bullet weights where used
Fact the ACOG is sighted for the lighter ammo
Fact the heavier ammo was still precise just not accurate to his zero
Assumption that 5.56 vs 2.23 has anything to do with it
Fact no 5.56 vs 2.23 thread has ever ended well

EvolutionGSR
04-17-2012, 3:03 PM
At 50 yards, I dont think the 7 grains of bullet weight should create 2 inches of bullet drop. Also OP at a 50 yard 0, the bullet is still going up at 100 yards relative to its elevation at 50 yards.

That being said, I dont know whats causing the issue. A guess would be that your 1/9 barrel is stabalizing the longer 62 grain steelr core bullet differently.

jonjonkills101
04-17-2012, 3:11 PM
my experience with this was with my 700 using .308.

im on point sub moa with FGMM at 100 yards, when i start using the lighter american eagle loads with the same zero as the FGMM i hit close to MOA about an inch up and inch to the right. so i would say normal, but it is a little weird that its off by that much though. maybe try adjusting your zero for the heavier rounds and switch back to the lighter and see if you get a consistent reversal? thats what i would try

SPECR
04-17-2012, 3:17 PM
Guys,

"man if I switched ammo's, I would have not even been able to hit a deer sized target at 100 yards, is this normal". Thats why I asked.

Thanks again.

Yep, that's why you zero your rifle/ scope with your hunting ammo at a distance you estimate your target to be.

MrPlink
04-17-2012, 3:18 PM
Different zero for different ammo, pretty normal. My .308 is zero'd with 168fgmm. I tried some 125gr hornaday for fun and they were almost 6inches high.