Highest speed possible with a .223cal bullet?

[Kenny474]

What is the maximum speed attainable with a .223 caliber bullet, and what type of bullet construction will be best for extreme velocity? Basically, at what point can you simply not go any faster without the bullet exploding?

I understand this question is subject to many variables, so I don't expect anything definite, just a round-about figure that has been attained but could not be exceeded.

I am curious as I have a project in the works with a 1-14" twist 27" .223 barrel that I plan to chamber in .22-6mmAI, and basically just want to see what kind of velocity is possible, and what happens when a varmint (PD, woodchuck, etc.) is hit at terminal velocity. I know longer would have been better for the barrel, but it was as long as I could get and it was dirt cheap.

I know Barnes has a 45gr Banded Solid, which I figure should hold up pretty well to extreme velocity, but will do little in terms of explosive effects on target. I figure other solid copper bullets will hold up decently as well, but I am not sure they will give the desired effect either.

Anybody have anything similar, maybe a .22-.284, .22-243, or some other super screamer?

 

[Preacher]

I was shooting a 22/6mm AI with 80 grain Bergers at over 3500 fps and they never made it to the target. With a slower twist they may have made it past the end of the barrel....The 75 A-max worked a little better, but not much..
Seems I slowed it down and ended up shooting the 80 gr Sierra's....
I would think with that big of a case you would want to use a solid copper bullet if your really going to lean on it hard....

 

[Kenny474]

What twist were you using? I guess it would need to be pretty fast for the 80gr Bergers.

I plan to push it as hard as I can just to see what velocity is attainable with the solids, but if I have to back it off to be usable and for expanding bullets to hold up, than I guess that's what will need to happen.

I doubt it will last very long, but as long as it makes it until I go to North Dakota for PD's next year and I can at least make a few hits with it on live game, then I really don't care.

 

[Preacher]

That rifle was a 8 twist, I recorded a few 75 A-max at a tiny bit over 4000fps.
Probably why the barrel didnt last very long..
I had that barrel rebored by Cliff LaBounty years ago to 6mm, and I left the chamber as it was, it still shoots 80 grain Fowlers really well...

 

[RonAKA]

I have been working with another fellow that shoots at our range. He has a 22/45T SMc. See this link:

http://www.superiorballistics.com/index.html

The designers of the cartridge claimed it should do 4980 with a 36 grain Barnes Varmint Grenade. He only got about 4300 out of it. He thinks the problem is the fast twist barrel he put it in. Having been trying to help him with the minimum twist he could get away with, so he can have a second try with a new barrel. The varmint grenade was the recommended bullet by the designers. In any case I came up with a minimum of 13 twist using the Don Miller formula, and the stability margin that Berger seems to use for flat base bullets 1.1. He has contacted Barnes and they say their varmint grenade is suitable for barrels from 7 to 14 twist, but caution that they will explode in the faster twists combined with the high velocity. It is the final spin rate that depends on both velocity and twist that makes them explode, not just velocity.

If you check out the Barnes reloading data site for the .224 bullets, you will see loads listed for the Weatherby, and Swift that are getting up in the 4400 fps range with the varmint grenade. They show a 25" barrel with a 14 twist. You would hope they would not show configurations that would not stabilize or would explode... I also see they show a 4500 fps load for the 22 WSSM, using a 10 twist.

It would also be interesting to see if the 30 grain varmint grenade intended for the Hornet would hold together at those high velocities and long twist rates.

http://www.barnesbullets.com/information/load-data/data-224/?PHPSESSID=2c410949a7b53b5d168842f06709299c

So I think 4500 fps likely possible especially in a 27" 14 twist barrel. 4980 I'm not so sure about...

 

[jonbearman]

Why not use 30 cal sabots out of the .308 and push a projectile at over 4230 fps with no bore wear. It is just a thought.

 

[Kenny474]

Why not use 30 cal sabots out of the .308 and push a projectile at over 4230 fps with no bore wear. It is just a thought.

Jon, I have tried that, and while velocity is good, accuracy has never been remotely good for me.

But I haven't played with them for a few years, so I may give them a shot again in my 1-10 .308, as I do have better equipment and also know a bit more as well.

I don't think it will quite give me the results I want though, but I still think I'll give them a go anyway.

I will have the .22/6mmAI reamer, brass and dies in a few weeks, and I have the barrel already, so I plan to chamber it up and let it rip and see what happens

 

[alf]

My 22-243 Middlested in a 26" 14 twist ran 40 gr Ballistic Tips at 4600.

 

[JRinCo]

On a somewhat related note that may interest you.
Several years ago on a whim I bought a box of Berger .224 30 grain varmint bullets. I've only tried them in my .223 Rem. standard chamber with a 26" 1 in 12 twist. Using H 335, accuracy is outstanding all the way out to 350 yards. And I'm getting 4000 fps with out any sign of pressure. Effects on PD's are impressive.

I do own a .22-250 that I haven't tried them in, I always figured that those bullets couldn't stand that much velocity.

 

[Ackman]

To see what it would do, a friend pushed the little 35gr Berger to 5100-5200 in a 22-284. He said it was very accurate at that speed.

 

[bozo699]

Kenny,
I am no longer a big advocate of ultra speed,but a few years ago I had a #70 coyote in 22-250 accuracy had fallen off a bit so I decided to rebarrel it. Before I did I wanted to see how fast I could get bullets to fly. It had a 1:12 on it and I had a lot of different 50 and 55 grain bullets on hand. most bullets were coming apart before I hit the target @ 100 yds when I got around 4000fps or so. My favorites @ the time were the 50 gr v-max bullets, they were coming apart @ about 3800 or so. The best varmint style bullets that I could make fly the fastest was 50 gr nosler b tips @ around 4800fps with decent accuracy for what the barrel was capable of. I would have pushed them faster but I couldn't stuff any more powder in them, not to mention pressures and if I remember right I got some 40 gr barns with there blue coated bullets right @ 5000 fps with great accuracy.When you hit a ground hog with them anywhere all you saw was a red mist in the scope When I tried to push tnt speer hp bullets over 3600 fps they came apart a few feet past the end of the barrel. Have fun w/that new build and by all means keep us informed.
Wayne.

 

[oldhoward]

I shoot the 36 grain Barnes varmint grenades out of a 220 swift at 4450 to 4500 fps. Accuracy is good and it is very explosive on pd's. You will become a member of the red mist society. heeheehee!

 

[RonAKA]

I shoot the 36 grain Barnes varmint grenades out of a 220 swift at 4450 to 4500 fps. Accuracy is good and it is very explosive on pd's. You will become a member of the red mist society. heeheehee!

What twist do you have in the barrel, and have you had any issues with the bullet blowing up before it gets to the target?

 

[Kenny474]

So I have one more question. Why is it that when I use the JBM stability calculator to try to get some predictions on what will actually stabilize from the 1-14" barrel, that even a 40gr Nosler Varmint BT @4500fps is predicted to be unstable? It should work, as I have seen 22-250's with 1-14" barrels that shoot this exact bullet without issue.

Is this just one of those instances where you can't go by the numbers and need to just rely on actual performance?

Thanks again for all the info and past experiences, it's all appreciated.

 

[Hamo]

My friends uncle uses a .223 projectile sabot'd in a .308 win. He claims with a light round he can get in excess of 5000fps. Dont know how accuracy is or how 'truthful' his stories are but its food for thought