Heavy Bullets in .223

[RecoilRob]

The original M16 used 1/14 which was the same as the .222, but proved to be marginally stable at longer ranges w/55 M193...so they switched to 1/12 and that was what we used in the M16a1's. These worked well most of the time, but if you got the morning relay on a cold and damp day the 500 yd results were likely to be worse than the afternoon guys as the rounds really did seem to be marginally stable out that far in the thick atmosphere.

The 1/7 twist they use today is mostly needed by the M856 tracer rounds which are considerably longer than the M855 ball and so need the extra twist to keep stabilized. 1/9 will normally stabilize the heavy bullets just fine though I guess it depends on manufacturer and barrel length along with the particular bullet being used as to whether you'll have good accuracy or not with the slower twist. That's why 1/8's were invented to be sure of enough spin for the heavy projectiles...and I'm of the opinion that 1/7 is probably not needed for most heavy bullet use....though some rifles using that twist shoot most excellently. Too much spin isn't a problem unless the projectiles rip themselves apart from excessive rotation but that's normally not seen in the shorter barrels. Now...long barrels with fast twist and very light bullets...that's a different story and they can rupture on the way to the target.

 

[salt&battery]

The original M16 used 1/14 which was the same as the .222, but proved to be marginally stable at longer ranges w/55 M193...so they switched to 1/12 and that was what we used in the M16a1's. These worked well most of the time, but if you got the morning relay on a cold and damp day the 500 yd results were likely to be worse than the afternoon guys as the rounds really did seem to be marginally stable out that far in the thick atmosphere.

The 1/7 twist they use today is mostly needed by the M856 tracer rounds which are considerably longer than the M855 ball and so need the extra twist to keep stabilized. 1/9 will normally stabilize the heavy bullets just fine though I guess it depends on manufacturer and barrel length along with the particular bullet being used as to whether you'll have good accuracy or not with the slower twist. That's why 1/8's were invented to be sure of enough spin for the heavy projectiles...and I'm of the opinion that 1/7 is probably not needed for most heavy bullet use....though some rifles using that twist shoot most excellently. Too much spin isn't a problem unless the projectiles rip themselves apart from excessive rotation but that's normally not seen in the shorter barrels. Now...long barrels with fast twist and very light bullets...that's a different story and they can rupture on the way to the target.

I had a Colt HBAR 1x7 twist chrome barrel it was as accurate as a bolt gun and it shot 52 grain bullets at 100 yds into tiny groups. I figure you cannot over stabilize a bullet but you can under stabilize one. at that time there were no heavier bullets beyond 55 grain. like you said if you used explosive varmint bullets with thin jackets the fast twist would spin the bullet apart. I sold it being I figured I could not go long range with it then the came out with the 69 grain bullet. wish I still had it with the bullets they got now

 

[C-grunt]

The heavier bullets make a big difference out past around 400 yards. The longest Ive shot a 5.56 rifle was right around 1000 meters with M262. Was accurate enough at that range that you wouldn't want to stand around in the open to long. Longest range I shot that I could have a pretty reasonable chance at a first round hit was 800 meters, and my biggest limitation at that range was the 4x ACOG.

On top of being better at long range the heavier bullets also have an advantage in terminal ballistics too. The 77 grain SMK bullet used in the M262 load is known to yaw and fragment down around 2000 FPS impact velocity. Below that it still yaws but wont always fragment. Im a big fan of the M262 load. A friend of mine has a confirmed kill at over 400 meters with it using his Mk18 (10.3 inch barrel).

 

[cdb1]

I load 64 grain PowerPoints for my AR and 65 grain Sierra GameKings for my sons AR, both 1:9 twist.

I sold firearms for two years and people were enamored with 1:7 twist AR's. I'm talking people who were only going to plink, and by their own admission were going to shoot the cheapest 55 grain ammo they could buy. When I told them a 1:9 twist was all they needed they flat out did not believe me.

 

[Varminterror]

I sold firearms for two years and people were enamored with 1:7 twist AR's. I'm talking people who were only going to plink, and by their own admission were going to shoot the cheapest 55 grain ammo they could buy. When I told them a 1:9 twist was all they needed they flat out did not believe me.

There are two players in that game:

1) .mil
2) Internet forums

"If .mil says AR's should be 1:7" twist, then why would I pick an inferior non-mil-spec twist? Especially since everyone online says I'll need a 1:7" twist to stabilize heavy bullets for long range shooting - which I've never done and will never likely do, but why would I limit myself?"

Every forum around the web has a "what twist in AR?" thread, or hundreds of them, so any time a would-be buyer goes looking, they find recommendations for 1:7".

One of my major frustrations with THR, in fact, is (what I consider to be) the absolutely ridiculous trend to adhere EXACTLY to .mil standards, or original M16 or M4 standards for AR-15's. Too many folks paint themselves into a corner with this idea that only ONE design works, and the rest are all inferior - whether it's complaining about Carbine buffer weights, commercial or light BCG's, carbine gas system lengths (which are naturally evil since the original design was a 12" gas system), non-mil-spec parts, you name it... If you follow the rifle section here for a while, you'll assuredly see these repeated threads where someone asks about building or tuning their AR, then a gaggle of luddites jump in and push these standards as if they came down on a tablet from Sinai. This neglects the fact many .mil models do NOT use these same standards, and the fact MILLIONS of AR's have been sold and operate just as well as any .mil M16 or M4 without meeting the exact same design criteria.

Of course, the only real downside to a would-be rifle buyer to irrationally select 1:7" ONLY is the fact they will miss out on buying opportunities for many fantastic models of AR which don't come with a 1:7". For a guy building their AR, it's largely irrelevant, as they can pick any barrel they want, and frankly, nobody can tangibly experience any significant downside of a 1:7" in a 16" carbine, at least not with any bullet I've ever fired. I've never been able to get a bullet to spin-fail out of a 1:7" 223/5.56. Out of a 26" barreled fast twist 22-250 and 22-243 - yup, I've made a few 45grn bullets into shotgun loads, but never in a 223/5.56 case, and certainly not in a 16" carbine.

 

[salt&battery]

There are two players in that game:

1) .mil
2) Internet forums

"If .mil says AR's should be 1:7" twist, then why would I pick an inferior non-mil-spec twist? Especially since everyone online says I'll need a 1:7" twist to stabilize heavy bullets for long range shooting - which I've never done and will never likely do, but why would I limit myself?"

Every forum around the web has a "what twist in AR?" thread, or hundreds of them, so any time a would-be buyer goes looking, they find recommendations for 1:7".

One of my major frustrations with THR, in fact, is (what I consider to be) the absolutely ridiculous trend to adhere EXACTLY to .mil standards, or original M16 or M4 standards for AR-15's. Too many folks paint themselves into a corner with this idea that only ONE design works, and the rest are all inferior - whether it's complaining about Carbine buffer weights, commercial or light BCG's, carbine gas system lengths (which are naturally evil since the original design was a 12" gas system), non-mil-spec parts, you name it... If you follow the rifle section here for a while, you'll assuredly see these repeated threads where someone asks about building or tuning their AR, then a gaggle of luddites jump in and push these standards as if they came down on a tablet from Sinai. This neglects the fact many .mil models do NOT use these same standards, and the fact MILLIONS of AR's have been sold and operate just as well as any .mil M16 or M4 without meeting the exact same design criteria.

Of course, the only real downside to a would-be rifle buyer to irrationally select 1:7" ONLY is the fact they will miss out on buying opportunities for many fantastic models of AR which don't come with a 1:7". For a guy building their AR, it's largely irrelevant, as they can pick any barrel they want, and frankly, nobody can tangibly experience any significant downside of a 1:7" in a 16" carbine, at least not with any bullet I've ever fired. I've never been able to get a bullet to spin-fail out of a 1:7" 223/5.56. Out of a 26" barreled fast twist 22-250 and 22-243 - yup, I've made a few 45grn bullets into shotgun loads, but never in a 223/5.56 case, and certainly not in a 16" carbine.

good post but the main reason AR's are so popular is because of the wars and soldiers using them. if the army ever switches to completely different rifle and round the AR's will end up in 55 gallon drums for $150 each. guys like to play GI Joe

 

[hdwhit]

Varmintterror wrote:
If you follow the rifle section here for a while, you'll assuredly see these repeated threads where someone asks about building or tuning their AR, then a gaggle of luddites jump in and push these standards as if they came down on a tablet from Sinai.

I've never been able to get a bullet to spin-fail out of a 1:7" 223/5.56. ... I've made a few 45grn bullets into shotgun loads, but never in a 223/5.56 case.

Back in the 1980's Hornady made some .224 bullets with a very thin jacket. I think they were called "SX" (for Super eXplosive). An insert in the box warned not to shoot them over about 2,800 fps since they might fail in flight. I loaded some of these back in the 1980's right at 2,800 fps and they would shoot fine out of my 1:12 Ruger but when I recently dusted some off and tried shooting them out of a 1:9 M&P-15, I got trails of grey vapor with no holes in the target. Other than that, I have never had a failure of a "normal" bullet attributable to a high twist rate, but I did choose a 1:9 AR for my sons since I wanted them to be able to reliably shoot 40 and 45 grain rounds which I do reload as well as bullets heavier than 60 grains.

 

[M1key]

That background music was a nice touch Armored...

M

 

[rskent]

good post but the main reason AR's are so popular is because of the wars and soldiers using them. if the army ever switches to completely different rifle and round the AR's will end up in 55 gallon drums for $150 each. guys like to play GI Joe

Or maybe they are popular because they are so versatile. Modify it into what you want. Build it from scratch.
Whatever you can dream up you can do to an AR. Pick your caliber and have at it.

AR’s are great.

 

[salt&battery]

Or maybe they are popular because they are so versatile. Modify it into what you want. Build it from scratch.
Whatever you can dream up you can do to an AR. Pick your caliber and have at it.

AR’s are great.

I like AR's and they are versatile and can be a very accurate semi auto. I have one in 223 and 308

 

[someguy2800]

good post but the main reason AR's are so popular is because of the wars and soldiers using them. if the army ever switches to completely different rifle and round the AR's will end up in 55 gallon drums for $150 each. guys like to play GI Joe

If thats the case then you better buy them up when it happens because I have been trying to find a nice M1 garand and they sure aren't giving those things away anymore!

 

[ford8nr]

If thats the case then you better buy them up when it happens because I have been trying to find a nice M1 garand and they sure aren't giving those things away anymore!

But I DO remember the days when Woolworths variety store had a gun department with Garands and M1 Carbines in fiber 55gal barrels. $95 for the Garand and $75 for the Carbines AND NO BODY WANTED THEM.
Arghhhhhhhhhhhhh

 

[ford8nr]

I shoot 55's in my 1/9 twist AR cause they are cheap and heavier bullets don't make much difference.
I shoot 69 or 75's in my 1/8 bolt cause they shoot much tighter and the added weight helps smack the steel rams at 200m

 

[Hardtarget]

I have a tendency to like heavier bullets. I like the 170 bullet for the .30-30. With my dad's 1903 Springfield it likes the 180 rn....don't know why. In my AR I like to shoot 62 gr bullets. Its a 1:9, 20" and shoots the 55 gr well but I have some Hndy 62 bthp that have grouped well. I don't have any competition experience and only 200 yd range at the club...I just like bullets in the mid/upper range. The heaviest I've used in .223 was the Sie. 69 bthp. It shot ok and I should try it again.

Fully understand looking for feed back. No reason to reinvent the wheel when you have access to the experience here on The High Road!

Mark

 

[salt&battery]

I have a tendency to like heavier bullets. I like the 170 bullet for the .30-30. With my dad's 1903 Springfield it likes the 180 rn....don't know why. In my AR I like to shoot 62 gr bullets. Its a 1:9, 20" and shoots the 55 gr well but I have some Hndy 62 bthp that have grouped well. I don't have any competition experience and only 200 yd range at the club...I just like bullets in the mid/upper range. The heaviest I've used in .223 was the Sie. 69 bthp. It shot ok and I should try it again.

Fully understand looking for feed back. No reason to reinvent the wheel when you have access to the experience here on The High Road!

Mark

what kind of powder have you used with the 69 grain bullets? AA 2520 and Rel 15 are excellent powders

 

[M1key]

Varget works great with the 69, 75, and 77 grainers out my ARs and Bolties. (1:9, 1:8, 1:7)

M

 

[Justin Thyme]

Building a 223 Wylde rig with 24 in BB just to I can work on expanding my comprehension of tailored heavy loads..as soon as I work out my gas block issues that is (posted thread on that this week).
I hope to work from 69 to 77 grains looking for that sweet spot.

 

[armoredman]

That background music was a nice touch Armored...

M

I am quite fond of the musical group Two Steps From Hell - they have tons of movie quality music.
Justin, what is the advantage a 223 Wylde over 5.56mm, if you don't mind me asking?

 

[salt&battery]

I am quite fond of the musical group Two Steps From Hell - they have tons of movie quality music.
Justin, what is the advantage a 223 Wylde over 5.56mm, if you don't mind me asking?

you are supposed to be able to fire 5.56 nato and commercial 223 ammo "safely" in the same rifle. looking to fix a problem that hardly exists

 

[C-grunt]

The Wylde chamber is a little tighter than the 5.56 but bigger than a .223 chamber. Supposedly improves accuracy but you can still shoot 5.56 out of it safely.

 

[Varminterror]

good post but the main reason AR's are so popular is because of the wars and soldiers using them. if the army ever switches to completely different rifle and round the AR's will end up in 55 gallon drums for $150 each. guys like to play GI Joe

I didn't say a word about why AR's are popular.

I spoke to my opinion as to why so many gun buyers insist on 1:7" barrel twist.

 

[salt&battery]

I didn't say a word about why AR's are popular.

I spoke to my opinion as to why so many gun buyers insist on 1:7" barrel twist.

please don't call the cops. but you did go on a long winded rant on why most guys want them in military configuration and I gave why I think the reason is. a 1x7 twist is what the military uses. I did not insult you but you saw fit to throw a dig at me. why is that?

 

[armoredman]

I got a 1-7 because that was what was available.

 

[redbullitt]

I have a nice bolt action 223 built to take the 80g bullets. It has a long 28 inch barrel and does a very good job with the heavier bullets. My SPR style AR shoots the 77smk very well too.

Probably the only caveat is that both rifles were set up with heavy bullets in mind, especially bolt action. On the flip side i have a 1/9 twist bolt action that shoots EXCEPTIONALLY well with 69 matchkings.

All three rifles have shot the light stuff too, but for the kind of shooting I do the heavier bullets tend to do better in the wind.

 

[cdb1]

I got a 1-7 because that was what was available.

And I would do the same.