Accurate 223 round for 1:8 twist

[peterk123]

I have a boatload of 55 grain. Great for general plinking but I just can't get great accuracy. Not even at a 100 yards. Is the round not getting stabilized and should I be going heavier, like 75 grains?

I'm trying to get the gun to be coyote ready. I always figured 55 grain was good in just about any AR.

 

[paul73]

 

[Marty McFly]

Lol

 

[paul73]

i did not know 1:14 barrels existed. interesting.

 

[Marty McFly]

i did not know 1:14 barrels existed. interesting.

What's up with the 80 grain 1/9 it's green red and yellow. f***ing schroedingers round

 

[LakeTrout]

That twist is fine for 55s. It’s the opposite of what you’re thinking. Takes a faster twist to stabilize heavier bullets.

 

[Woodsloafer]

i did not know 1:14 barrels existed. interesting.

My Ruger 77/22 22 Hornet has a 1:14

 

[peterk123]

i did not know 1:14 barrels existed. interesting.

I think the original AR came with that because the army was lobbing light bullets.

I'm shooting cheap bulk ammo, steel case. It really shouldn't matter at 100 yards, at least that's what I thought. I'm not sure I'm even getting 2 inch groups. I'm not the best shot. But I'm not that bad.

The gun is an M&P Volunteer DMR. It has a 20 inch barrel.

 

[Mountain]

I have a boatload of 55 grain. Great for general plinking but I just can't get great accuracy. Not even at a 100 yards. Is the round not getting stabilized and should I be going heavier, like 75 grains?

I'm trying to get the gun to be coyote ready. I always figured 55 grain was good in just about any AR.

69 or 77 grain will work great.

 

[PappyM3]

1:8 twist is a great twist rate. Note that the only time you need to worry about going to light is when using cheap ammo. Faster twists can accentuate imbalances in cheap light bullets and produce less precision than slower twists, but “overstabilization” isn’t a thing the way people think about it. If you’re shooting good quality light bullets, then they’ll shoot good even in a 1:7 twist.

69gr SMK seems to be one of the most easily precise bullets for ARs particularly 1:8 twist. It’s my baseline when testing a new barrel. And it’s great for a few hundred yards. Starts to suffer to wind more than the 75/77gr crew past that.

On the high end, you’ll be able to easily stabilize anything seated to mag-length. 1:8 will also shoot 80gr SMK just fine. But it may have issues with 80gr ELD-Ms; they are longer. But all 80gr loads need to be hand fed into the ejection port so it’s not a concern to most.

 

[Mountain]

View attachment 818236

"Assumes nominal velocity of 2800 fps"

No, you can't assume that for the lighter bullets.

The upper right two cells in that chart should be red for the 45 grain bullets, and probably the 3rd one for 1/8 as well. There are no minimum loads below 3,000 fps for 45 grain bullets and the average loads are going to be ~3,400 fps. At such velocity the rotational speed of the 45 grain bullets will be high enough to at least become unstable and keyhole- if they even hit the target. Probably the bullets will disintegrate with a loud pop before they get much farther than ~25 yards.

 

[Mountain]

1:8 twist is a great twist rate. Note that the only time you need to worry about going to light is when using cheap ammo. Faster twists can accentuate imbalances in cheap light bullets and produce less precision than slower twists, but “overstabilization” isn’t a thing the way people think about it. If you’re shooting good quality light bullets, then they’ll shoot good even in a 1:7 twist.

What's a good quality light bullet that will shoot well in a 1:7? I've already ruled out Sierra, Nosler, Berger, and Hornady. IMHO it's the rotational speed, not the bullet.

Maybe 50's are OK? 45's and 40's keyhole and/or go pop.

I do agree that 1:8 is a nice all around twist rate.

 

[BostonVI]

Having had the same questions myself, I recently decided to test each of my ARs with a variety of loads to see what they prefer.

This is shot from a BCM Mk2 Stainless 18in 1/8 twist zereod for 77gr Federal Gold Medal Matchking.


I try to keep a variety of loads in inventory for testing before I commit to stocking up on a particular load.

 

[pupchow]

I have a boatload of 55 grain. Great for general plinking but I just can't get great accuracy. Not even at a 100 yards. Is the round not getting stabilized and should I be going heavier, like 75 grains?

I'm trying to get the gun to be coyote ready. I always figured 55 grain was good in just about any AR.

My Windham VEX (20" 1:8) does better than dime-sized groups @ 100 yards, with off the shelf Hornady 55gr V-MAX. M193 out of the same gun has nowhere near the same precision.

 

[PappyM3]

What's a good quality light bullet that will shoot well in a 1:7? I've already ruled out Sierra, Nosler, Berger, and Hornady. IMHO it's the rotational speed, not the bullet.

Maybe 50's are OK? 45's and 40's keyhole and/or go pop.

I do agree that 1:8 is a nice all around twist rate.

Rotational speed is definitely part of what I’m talking about.

Never tried below 50gr. Too much of a chance of pulling the bullet apart and I don’t actually know of any solid copper bullets that light. Precision doesn’t matter if the bullet blows up right past the muzzle. It could be the ones that don’t blow up are still deformed by the rotation, but if the bullet could stay totally intact, “over-stabilizing” wouldn’t actually cause it to become unstable.

50gr+ definitely seems to be dependent on bullet quality for precision. Blitzkings can be shot well in 1:7 twists. But, I’ve found that bulk M193 generally shoots better out of 1:9 twist barrels than 1:7 twist. Obviously it’s still not a precision load in 1:9 twist barrels, but better performance than 1:7. Like 2 MOA vs 3-4 MOA.

 

[peterk123]

How much does length of barrel play a role when it comes to bullet weight? 16 vs 20 inch, for example?

 

[Qwikdraw45]

i did not know 1:14 barrels existed. interesting.

Only in the Armalite version of the M-16 for 5.56. The bullet was unstable, so it tumbled when it hit and did quite a bit of damage (from what I've read) against unarmored targets. The Air Force tested it in arctic conditions and found it to be too unstable in the extreme low temps, and got them to change the twist rate to 1:12. Not as effective after that against the original targets. Leave it to the AF to Frig up something.

 

[Qwikdraw45]

How much does length of barrel play a role when it comes to bullet weight? 16 vs 20 inch, for example?

Apparently a good bit. Reports were that in Iraq, 14.5in was OK. A former co-worker wanted the 16in civilian version since he said it was similar to what he used there. He felt it was good for clearing buildings with the shorter barrel. In Afghanistan, I've read that due to the longer distances, troops wanted the longer 20in barrels to help reach out and touch someone. Only what I've read. Never deployed there myself.

 

[PappyM3]

How much does length of barrel play a role when it comes to bullet weight? 16 vs 20 inch, for example?

Between 16” and 20”? Very little in terms of stability factor. Velocity is a weak factor when it comes to stability. It takes a lot of velocity to influence stability. But, if your twist rate is on the edge of stabilizing a particular bullet, then you could find it too unstable in an 11.5”, but stable in a 20”.

 

[peterk123]

Only in the Armalite version of the M-16 for 5.56. The bullet was unstable, so it tumbled when it hit and did quite a bit of damage (from what I've read) against unarmored targets. The Air Force tested it in arctic conditions and found it to be too unstable in the extreme low temps, and got them to change the twist rate to 1:12. Not as effective after that against the original targets. Leave it to the AF to Frig up something.

Didn't they want the bullet to tumble in combat situations, for max trauma? Tear up a leg and you effectively have taken four soldiers out of combat. Kill them with one shot, you have only taken out one. I could have sworn I read about that somewhere.

 

[Qwikdraw45]

Didn't they want the bullet to tumble in combat situations, for max trauma? Tear up a leg and you effectively have taken four soldiers out of combat. Kill them with one shot, you have only taken out one. I could have sworn I read about that somewhere.

Apparently the SF advisors love what the original bullet/twist did. It took the Air Force (like most of them are never actually going to use a hand-held weapon) to Eff it up.

 

[JDL]

Replace your barrel

 

[PappyM3]

Didn't they want the bullet to tumble in combat situations, for max trauma? Tear up a leg and you effectively have taken four soldiers out of combat. Kill them with one shot, you have only taken out one. I could have sworn I read about that somewhere.

Not sure if tumbling was previously an intent for military bullets, but M193 fragments in tissue, which is much more effective at turning temporary stretch into permanent wounding. The tears from the fragments reduce the elastic limit of the tissue. Ever since Fackler, we’ve known that. Now, tumbling is better than a bullet ice picking through because it simulates a bullet having a much larger meplat, but is not as good as fragmenting. M855 and M855A1 are both intended to fragment as well, but with the addition of penetrators for barriers/cover.

 

[PappyM3]

Apparently the SF advisors love what the original bullet/twist did. It took the Air Force (like most of them are never actually going to use a hand-held weapon) to Eff it up.

Having an unstable bullet is not a good thing. It severely reduces ballistic coefficient and precision during external ballistics and would also likely reduce penetration in terminal ballistics.

The Air Force was right on that one.

 

[peterk123]

Not sure if tumbling was previously an intent for military bullets, but M193 fragments in tissue, which is much more effective at turning temporary stretch into permanent wounding. The tears from the fragments reduce the elastic limit of the tissue. Ever since Fackler, we’ve known that. Now, tumbling is better than a bullet ice picking through because it simulates a bullet having a much larger meplat, but is not as good as fragmenting. M855 and M855A1 are both intended to fragment as well, but with the addition of penetrators for barriers/cover.

That's cool stuff. Sick, but cool., haha. I figured a Spitzer style bullet would eventually tumble because the back end is heavier than the front. So momentum at some point when it starts to slow would cause the tumble.

 

[PappyM3]

I have a boatload of 55 grain. Great for general plinking but I just can't get great accuracy. Not even at a 100 yards. Is the round not getting stabilized and should I be going heavier, like 75 grains?

I'm trying to get the gun to be coyote ready. I always figured 55 grain was good in just about any AR.

Sorry, back to the topic, I missed the coyote part. What 55gr have you tried so far? FMJs? If so, they’re not known for their precision. Try 55gr V-Max, Blitzking, or varmageddon if you haven’t already.

That's cool stuff. Sick, but cool., haha. I figured a Spitzer style bullet would eventually tumble because the back end is heavier than the front. So momentum at some point when it starts to slow would cause the tumble.

A lot do tumble eventually, even after fragmenting or expanding. But it’s usually after most energy is transferred from good bullets and I haven’t heard of it being the primary intended wounding mechanism for any modern bullets. Who knows, maybe the Russians do.

 

[peterk123]

Sorry, back to the topic, I missed the coyote part. What 55gr have you tried so far? FMJs? If so, they’re not known for their precision. Try 55gr V-Max, Blitzking, or varmageddon if you haven’t already.

Yes fmj. Thanks! I will take a look. I have not had a chance to shoot this gun much because any time I had time this year I worked on shooting my hunting rifle. Time for me to get this gun working. Maybe I pick up a box of one these and also try something in the 75 gr range.

I just found a review of my AR and the author was getting 1.5 groups with it using 55gr. He swapped to 77gr and the group closed up nice and tight. 1.5 at 100 is just not tight enough for me. That's just a hot mess at longer distances.

 

[Qwikdraw45]

Having an unstable bullet is not a good thing. It severely reduces ballistic coefficient and precision during external ballistics and would also likely reduce penetration in terminal ballistics.

The Air Force was right on that one.

But that was the part the the SF advisors reported favorably on. Long time since I've seen the article. They were reporting that the bullets were hitting and tumbling, and it was doing a lot of damage to the inteded targets (small-statured, unarmored individuals). They weren't thinking about penetration or stability at close range.

As for the Russians, they had that 76N round in 5.45x39. Enclosed hollowpoint; heavy ass end. Tumbled and supposedly did well.

 

[PappyM3]

Yes fmj. Thanks! I will take a look. I have not had a chance to shoot this gun much because any time I had time this year I worked on shooting my hunting rifle. Time for me to get this gun working. Maybe I pick up a box of one these and also try something in the 75 gr range.

I just found a review of my AR and the author was getting 1.5 groups with it using 55gr. He swapped to 77gr and the group closed up nice and tight. 1.5 at 100 is just not tight enough for me. That's just a hot mess at longer distances.

The heavier bullets will kill the coyotes well too. Just wasn’t sure what sorts of considerations you had for pelts.

 

[PappyM3]

But that was the part the the SF advisors reported favorably on. Long time since I've seen the article. They were reporting that the bullets were hitting and tumbling, and it was doing a lot of damage to the inteded targets (small-statured, unarmored individuals). They weren't thinking about penetration or stability at close range.

Yeah, and it would have been and incredibly bad decision to stay with an unstable system because it worked in that very narrow CONOPs. SF aren’t always right, and the Air Force was in this.

Also, M193 when properly stabilized and fragments creates better wounds than just tumbling.