.223 Twist Rates revisited


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Red Tornado
September 28, 2005, 11:53 AM
Okay, the .223 is calling and I need to add one to my stable. I've narrowed down my choices and studied twist rates, but there's one thing that keeps bothering me. Which is optimal for the proper bullet.

The 1 in 12 works for 55 grain down, while apparently I need a 1 in 9 for 62 grain or higher, but it will still work for the 55 grain as well.

But which is more accurate? A 62 grain in a 1/9 or a 55 grain in a 1/12 twist, or a 55 grain in a 1/9 twist?

This is on a range gun, so I can commit to using one weight or the other, and I'm just looking for the smallest groups. Any input is appreciated.
TIA
RT

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wanderinwalker
September 28, 2005, 12:10 PM
Theoretically, the 1:12" twist coupled with the lighter-weight bullets should give you the best accuracy at 100 and even 200 yards. The 1:9" will give you the option of shooting up to 75gr bullets, improving your wind-drift performance out to 300 yards or so, while still allowing you to spin those little pills up close.

I shoot an AR-15 with a 1:8" twist for 80gr bullets out to 600 yards, and will be replacing the barrel shortly with a 1:7" twist barrel, as spitting heavy bullets at heavy charges seems to eat these faster-twist barrels. (Mine is OK, but the 200-yard groups have opened up. Still hammers with 80s at the 6 though, as I fired a 94-5X in the P-100 at Perry, putting my first round into the 7-ring!)

Pick the rifle you like, and take the barrel that is on it. I suspect, to a point, barrel quality is more important for accuracy with the shorter bullets, whereas the longer rounds need more spin.

GunGoBoom
September 28, 2005, 12:26 PM
I consider that I have 2 of the 3 bases covered in .223.

1. 1 in 12", or 1 in 14. 1 in 12s are good for 35-55 grain, though some say up to 62 gr if your rifle happens to like them. 1 in 14s are good for 35-50/52, and perhaps up to 55. My Handi has 1 in 12 twist.

2. 1 in 9, or 1 in 10. Versatile; do-it-all. Won't spin apart 45s or 50s, but probably would disintegrat 35s or 40s. Work very good with 55s. Work great with 62s. Will handle up to 69/70s. Perhaps up to 77s even if your rifle likes them. My AR has this rate.

3. 1 in 7, or 1 in 6.5. I don't yet have a rifle in this category. But 1 in 7 will handle up 90 grain, and 1 in 6.5 supposedly up to 100 gr (if anyone even makes those anymore). Dunno the bottom limits for these 2, but I suspect that 1 in 7s would work fine with 62s, but notsomuch with 55s.

But some of this depends upon not only bullet weight, but also bullet shape, and therefore how much bearing surface there is between the bullet and rifling.

Red Tornado
September 28, 2005, 01:36 PM
Great, thanks guys.

GGB, the Handi is one I'm considering, what is it's favorite load. Does it like the 55gr okay, and have you even tried the 62gr in it?

The other I'm considering is the Savage (the 1 in 9 may have given that away) since I'll be shooting mostly WWB, surplus, or (insert color) bear if the rifle likes it. This seems to be most versatile, correct?
Thanks,
RT

DMK
September 28, 2005, 02:22 PM
since I'll be shooting mostly WWB, surplus Surplus ammo might be a problem for you. Do those rifles have .223 or 5.56 chambers?

You can shoot .223 in a 5.56 chamber (or both in a Wylde chamber), but you can't shoot 5.56 in a .223 chamber.

Grump
September 28, 2005, 02:38 PM
Unless you're shooting projectiles BETTER than surplus and/or 55-gr FMJBTs, especially with a channelure, you are unlikely to see much of an accuracy difference between 1:12 and 1:9 twist barrels. Regardless of barrel quality, getting less than 2 MOA with that ammo is a gift/bonus/gravy/luck.

Me, I'd just go with the 1:9. I'm unlikely to need "accurate" tracers in arctic conditions, and I'm not planning to shoot 80-grain cheater-longloaded rounds.

If it don't fit in the magazine, you ain't competing as a SERVICE rifle any more. :cuss:

Red Tornado
September 28, 2005, 03:20 PM
DMK,
That's what I've been reading, but I've also read several things from people who have shot milsurp with no problems in commercial rifles. In a single shot or bolt action it seems (from stuff I've read) to be less of a problem than in autoloaders. Am I offbase here?

I'd love a .223 Wylde, but those are only custom, aren't they? Does anybody chamber Wylde in an off-the-rack rifle? I'm just getting my first .223, and I'm not going to spend a whole lot, probably $400 or less if possible.
Thanks,
RT

vanfunk
September 28, 2005, 04:57 PM
I can at least comment on my experience with AR-15 rifles and twist rates:

Although technically it is not the weight, but the length of the bullet that determines the most effective twist, most find weight to be the easiest predictor of performance.

1/12" twist: will stabilize 55 grains and under. 62 grain surplus begins to yaw and keyhole after about 80 yards.

1/9" twist: will stabilize bullets ranging in weight from 40 grains to 75 grains. Certain individual barrels that run "fast" may be able to handle the 77's.

1/7" twist: my favorite. Will stabilize bullets from 40 grains to 77 and beyond. 40 grain varming bullets with very, very fragile, thin jackets may spin themselves apart as soon as they leave the confines of the barrel. I shoot 55 grain bullets into tiny little groups with my 1/7" AR's, so accuracy is not affected to any discernible degree. I recommend 1/7" as the best "all around" twist, unless one plans on shooting alot of the really itty bitty varmint bullets.

HTH,
vanfunk

Jim Watson
September 28, 2005, 05:59 PM
I agree with Grump. For cheap ammo the main thing is to get enough twist to stabilize the longest/heaviest bullet you expect to shoot. That probably means a 1 in 9 for the 62 grain three-piece M855/SS109. Then if you get serious, you will be just right for the 69 grain match bullets which are very good to 300 yards and ok at 600; and can still expect excellent accuracy with the 52 grain benchrest bullets at 100-200. If you want more than that, you will likely be ready for a new rifle anyhow.

How much choice do you get in a factory rifle, anyhow? Not much. I don't know what H&R uses, though they will tell you if you call. Savage is 1 in 9 these days.

MechAg94
September 28, 2005, 05:59 PM
Does barrel length affect this analysis at all?

Bartholomew Roberts
September 28, 2005, 07:59 PM
Yes, on marginal twist rates a longer barrel can help you shoot a heavier load. To use one personal example, a 1/9 16" may or may not fire 75gr ammo well at 100yds (not well being 4-5 MOA); but a 1/9 24" barrel almost always does well with 75gr (sub-MOA) at the same distance.

1/7 will have no difficulties at all shooting 55gr ammo well. Personally, I think 1/7 gives you a lot more flexibility in your choice of ammo.

DMK
September 28, 2005, 09:22 PM
That's what I've been reading, but I've also read several things from people who have shot milsurp with no problems in commercial rifles. In a single shot or bolt action it seems (from stuff I've read) to be less of a problem than in autoloaders. Am I offbase here? That's a good question and I don't know the answer. I hope somebody here knows. It's probably similar to shooting 7.62x51 surplus in a commercial .308 gun. I'll bet if you asked the gun's manufacturer, they'd say "no way and don't even bother having your lawyer call us if it blows up on you".

I'd love a .223 Wylde, but those are only custom, aren't they? Does anybody chamber Wylde in an off-the-rack rifle? I wouldn't think it would be especially difficult for a good gunsmith to ream a .223 out to a Wylde (which of course would void your warrantee).

You're talking bolt action here though, it's probably not worth the cost or risk. You aren't going to be burning up cases of ammo with it like you would in a mini-14 or AR. Just buy some Black Hills Blue Box FMJ(very excellent ammo BTW even though it is reloads) or Winchester Whitebox 223 for plinking ammo. It's not terribly too much more than surplus. Surplus 5.56 is getting harder to come by now anyway so the point may almost be moot soon.

nipprdog
September 28, 2005, 09:39 PM
the Handi is one I'm considering, what is it's favorite load. Does it like the 55gr okay, and have you even tried the 62gr in it?

the hands down favorite load of the Handi rifle is the winchester 45gr jhp varmint. its the most used round by Handi owners that don't reload.
posts with good results using 62gr are rare on the NEF forum.

The other I'm considering is the Savage (the 1 in 9 may have given that away) since I'll be shooting mostly WWB, surplus, or (insert color) bear if the rifle likes it. This seems to be most versatile, correct?

having owned a handi and a savage, the savage will be more versatile. and more reliable with surplus ammo.

and I'm just looking for the smallest groups.

however, the smallest groups can't be had with the ammo you listed.

I'm predicting a future thread;

"My Handi/Savage rifle won't group worth a darn, please help"
;)

:D :D :D

Bartholomew Roberts
September 28, 2005, 11:33 PM
That's what I've been reading, but I've also read several things from people who have shot milsurp with no problems in commercial rifles. In a single shot or bolt action it seems (from stuff I've read) to be less of a problem than in autoloaders. Am I offbase here?

The short leade of .223 SAAMI will create higher pressures in any rifle firing 5.56mm NATO ammo. Signs of these higher pressures will be brass sticking to the chamber walls longer and popped primers. These symptoms of high pressure tend to make themselves immediately evident in semi-autos because the brass sticking to the chamber walls longer, affects cycling and popped primers end up wedged in gas keys, between bolt and chamber, or stuck in the fire control group.

In a bolt action or single shot you may be less likely to see these things because the primer may be less likely to fall into a sensitive area and the brass will have more time to shrink away from the chamber wall by the time you begin to extract. However, there will still be higher than normal chamber pressures. I don't know of any manufacturers who recommend firing 5.56mm from a .223 SAAMI chamber. Having said that, I've never read or heard of any safety issues from firing 5.56mm NATO from a .223 SAAMI chamber. All of the issues I am aware of are the functional ones mentioned above and apply mostly to semis.

Cueball
September 29, 2005, 02:30 AM
I have a Savage myself in .223 and use the 55gr bullets. It shoots them great with excellent accuracy. I've had good luck with others as well such as the 62 gr but I like and use the 55gr most often.

GunGoBoom
September 29, 2005, 10:54 AM
Tornado, sound like nipprdog has you covered there - I have not yet wrung out my new handi - but I'd suggest you get some info where I got most of mine - over at graybeard's handi forum:

http://www.graybeardoutdoors.com/phpbb2/viewforum.php?f=126

Those guys know some stuff. I was parroting what I've heard at graybeard's about the 1 in 12 handis, and just recently got mine. Good luck.

Coltdriver
September 29, 2005, 11:03 AM
I have always been curious about the ballistics of long range .223 shooting with the heavier 65+ grain bullets.

At the mid point along the way to a 300 yard target how high are you??

At 600 yards the arc has to be considerable! I am thinking maybe two or three feet at the mid point along the way to a 600 yard target?

I reload .223 for a 1 in 12 twist Ruger #3 but I have only reloaded in the 35 to 45 grain bullet range. I set mine to shoot very flat but point blank range is under 200 yards.

Jim Watson
September 29, 2005, 11:23 AM
Just been working up a Long Range AR for the Sierra 90 grain MK.
When zeroed at 600 yards, it is about 33 inches up at 325 yards. The more common 69 grain MK would be about 35 inches high at midrange.

Red Tornado
September 29, 2005, 01:49 PM
however, the smallest groups can't be had with the ammo you listed.
I'm predicting a future thread;
"My Handi/Savage rifle won't group worth a darn, please help"

Right Nipprdog, just most of my shooting will be cheap stuff. I'll get some better stuff to actually test maximum performance. Of course my ongoing complaint still stands.
"None of my rifles group worth a darn but they work for my friend, please help"

Actually grouping would be great, I usually "pattern" my rifles. ;)

Thanks for all the input guys, I've learned a bunch. Thanks for the link GGB, I'm sure that'll help.
RT

wanderinwalker
September 29, 2005, 05:13 PM
My experience with long-range .223 is throwing an 80gr Nosler J4 (similar to a Sierra MatchKing) at 2600fps or so. Out of my AR, my comeup from 300 to 600 is about 20 clicks, or 10 minutes, so 60 inches of drop between 300 and 600. But guess what? It isn't that much different from a .308 out of a 14. No matter how fast you drive a bullet, drop becomes an issue after about 400 yards or so.

And FWIW, I very, very rarely see folks shooting big magnums at 600. The hot-rods seem to be 6.5-284s, a few .284s, a smattering of 6.5-08s and an odd .30/.338. The hottest round I've seen a competitor use XTC is a 6.5-08.

Bartholomew Roberts
September 29, 2005, 09:12 PM
From a 50yd IBZ, I'm seeing around 52" of drop at 500yds using 55gr Q3131A. I usually use an ACOG for those ranges since I can barely make out the target using only my eyes. The ranging tree of the ACOG makes calculating the drop for different distances pretty easy.

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