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I decided to shoot my 12.5” barrel AR-15. I wanted to see if I can zero in at 200 yards. The wind was around 15mph coming directly uprange. But I was thinking a 5.56 at 200 yards shouldn’t matter unless it’s crosswinds over 15mph. I’m kind of a new shooter. Just picked up my first rifle 11 months ago. With that said I can shoot 1/4 MOA at 300 yards with no wind with a 300 Win Mag. So I know how to fire a rifle. With cheap factory federal ammo, I couldn’t get under 1 MOA USING a Caldwell 7-Rest. In fact I barely shot 1MOA. Each of my groupings has its own adventure.

So what gives? If Marines shoot them at 500 yards using iron sights, I should be able to shoot tight groups at 200 yards with a scope.


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I decided to shoot my 12.5” barrel AR-15. I wanted to see if I can zero in at 200 yards. The wind was around 15mph coming directly uprange. But I was thinking a 5.56 at 200 yards shouldn’t matter unless it’s crosswinds over 15mph. I’m kind of a new shooter. Just picked up my first rifle 11 months ago. With that said I can shoot 1/4 MOA at 300 yards with no wind with a 300 Win Mag. So I know how to fire a rifle. With cheap factory federal ammo, I couldn’t get under 1 MOA USING a Caldwell 7-Rest. In fact I barely shot 1MOA. Each of my groupings has its own adventure.

So what gives? If Marines shoot them at 500 yards using iron sights, I should be able to shoot tight groups at 200 yards with a scope.


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Well in the USMC we use the M4 with a 14.5 inch barrel and a 1:7 twist. We use the 62gr 5.56 NATO cartridge.

I would suggest maybe try different 5.56 weights or inspect your barrel maybe it's seated incorrectly.


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I decided to shoot my 12.5” barrel AR-15. I wanted to see if I can zero in at 200 yards. The wind was around 15mph coming directly uprange. But I was thinking a 5.56 at 200 yards shouldn’t matter unless it’s crosswinds over 15mph. I’m kind of a new shooter. Just picked up my first rifle 11 months ago. With that said I can shoot 1/4 MOA at 300 yards with no wind with a 300 Win Mag. So I know how to fire a rifle. With cheap factory federal ammo, I couldn’t get under 1 MOA USING a Caldwell 7-Rest. In fact I barely shot 1MOA. Each of my groupings has its own adventure.

So what gives? If Marines shoot them at 500 yards using iron sights, I should be able to shoot tight groups at 200 yards with a scope.


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My first question would be whats your twist ratio and bullet weight?

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You are comparing a bolt gun with a gas gun. 12.5" barrel is designed for battle accuracy not for sniper accuracy. 12.5" AR is CQB oriented. Of course it will hit the man size target out 300 - 400 yards no problem, but it's not gonna give the clover leaf.

I have a MK12 clone shooting 77gr. I even handload the ammo to mimic MK262 and still only able to produce around 1 moa.

One more thing, it takes little practice to shoot the gas gun for accuracy even it's coming out of small frame AR.
 

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You are comparing a bolt gun with a gas gun. 12.5" barrel is designed for battle accuracy not for sniper accuracy. 12.5" AR is CQB oriented. Of course it will hit the man size target out 300 - 400 yards no problem, but it's not gonna give the clover leaf.

I have a MK12 clone shooting 77gr. I even handload the ammo to mimic MK262 and still only able to produce around 1 moa.

One more thing, it takes little practice to shoot the gas gun for accuracy even it's coming out of small frame AR.
While that in general is true, I wouldn't just assume that all of that is the case. If he is using wrong ammo and weight, that can play a very big part. Good barrels even when short can achieve good accuracy just less velocity. I have a few ARs 15 and 10 from 16" to 24" that I will put against any bolt gun ive seen. The days of ARs only being "minute of man " are past, you can build them as accurate as you desire

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While that in general is true, I wouldn't just assume that all of that is the case. If he is using wrong ammo and weight, that can play a very big part. Good barrels even when short can achieve good accuracy just less velocity. I have a few ARs 15 and 10 from 16" to 24" that I will put against any bolt gun ive seen. The days of ARs only being "minute of man " are past, you can build them as accurate as you desire

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I've seen some great shooters with high end parts and with some custom touch, but those were all 18" or 20". But, 12.5" or any SBR type? I don't know. I never seen one nor heard of one.
 

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I've seen some great shooters with high end parts and with some custom touch, but those were all 18" or 20". But, 12.5" or any SBR type? I don't know. I never seen one nor heard of one.
I've shot a SBR and some have been crap, some have been lasers, all I was getting at is I would make sure hes matching his ammo type and weight before i started looking for something to be wrong but you are in general correct about SBR, they typically are meant for close quarters urban combat, close self defense.

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I very much agree with what Ted said I would also like to add maybe try a 72 grain as well

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Really 1/7 should be able to handle up to 80gr but 55 will fly all over the place.. if its NATO chamber also make sure your not using 223 rem, stick with 5.56 NATO loads

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Really 1/7 should be able to handle up to 80gr but 55 will fly all over the place.. if its NATO chamber also make sure your not using 223 rem, stick with 5.56 NATO loads

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With my M4 1/7 I threw 20 rounds of 72gr 5.56 and it blew my mind. Absolutely incredible change in accuracy. She isn't a bolt gun obviously but I would definitely just throw it out there. Think about Barrel harmonics as well. The longer the barrel with the tighter twist the heavier you should go. I may be wrong but that's what I've always been taught and it has always worked great for me.

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With my M4 1/7 I threw 20 rounds of 72gr 5.56 and it blew my mind. Absolutely incredible change in accuracy. She isn't a bolt gun obviously but I would definitely just throw it out there. Think about Barrel harmonics as well. The longer the barrel with the tighter twist the heavier you should go. I may be wrong but that's what I've always been taught and it has always worked great for me.

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That is true:) I would guess he will find his best at either 68 and or 72gr, hopefully it will do 62gr just fine so he can have m855.. ive never seen light ap in heavier.. maybe its there and I've just never noticed:)

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That is true:) I would guess he will find his best at either 68 and or 72gr, hopefully it will do 62gr just fine so he can have m855.. ive never seen light ap in heavier.. maybe its there and I've just never noticed:)

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Hey man we're all here to learn I learn new s*** every day from people whom I never expect to teach me something. As long as we all remember to be respectful to one another and hear each other out I think we will be much better off as a community.

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The term barrel harmonics was used. I’ve been reloading and had some success dialing in loads for different rifles. I suspect barrel harmonics and selecting the right bullet weight for the barrel twist had something to do with getting bug holes in paper. I’m wondering if tuners can modify the Barrel harmonics to a factory load instead of modifying the load to the harmonics to get to those magic holes at 100.. Just a thought.
 

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Discussion Starter #20
I just looked up “barrel harmonics”. That’s another piece of knowledge I now have. But the bummer is, it seems like it can only be solved with a more expensive barrel. But that makes sense. I think that one applies more to my 24” barrel Savage than the 12.5 barrel. So a smaller barrel seems like there are slight advantages in terms of harmonics since they don’t whip around as much.


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