.223 80 gr. Hor

[MGYSGT]

According to load tables, the 80 gr Hornady fired at 2800 f.p.s. will still be going 1600+ f.p.s. at 1000 yrds. Even though that is still supersonic, at what velocity can I expect the projectile to become unstable in a 1:8 twist barrel?

Tom

 

[wc872]

I think you should be alright down to 2500 fps or so.

 

[MrMajestic]

Tom, Are you referring to rotational speed or transonic velocity as the cause of the instability? Once the SG, of the preferred value of 1.3, is reached rotation is no longer an issue even as velocities fall as they do not decrease, at least not as quickly as the velocities. I guess there are the borderline stability SG numbers that could cause an issue but you don't seem to be even close to them. Now entering that transonic velocity of Mach 1.2-1.3 that's a different story. Some bullets handle it much better than others and I highly recommend reading Brian Litz's studies as he is far more knowledgeable than I when it comes to this stuff. I just struggle to know enough to attempt to stay out of trouble!

 

[MGYSGT]

So if I did my math correct, Trans Sonic can be at the 1440 F.P.S. on the high end, depending on the bullet design? I thank you for the answer.

Tom

 

[BoilerUP]

The 80gr A-Max is only considered marginally stable from a 1:8 barrel using traditional stability formulas. Of course, a 'marginally' stable bullet can still be accurate...

Example:
80gr A-Max @ 2735fps (fireform load for my 22" 223AI)
500' ASL
59°F
29.92" Hg
0% humdity
Stability factor: 1.17

Change temp to 85°F, stability goes to 1.23
Change temp to 20°F, stability goes to 1.08
Temp @ 59°F, change elevation to 2500 ASL, stability goes to 1.26
Temp @ 20°F, elevation 2500 ASL, 1.16"

 

[nfhjr62]

What barrel length are you using myself am using a 24 inch 1/8 barrel and have had good results at 100 yards so far.

 

[MGYSGT]

26" Criterion in 1:8. Shot a 400-25X a few weeks ago with it at our 300 yrd range. Would like to shoot at other places with longer ranges.

Tom

 

[clatarar]

Google "shooting .223 to a mile"... based on what mystic does there, i think you'll be fine out to 1000 yards....

 

[BoilerUP]

[quote author=gstaylorg] For 1000 yd, you'd really want to be pushing the 80 Amax at about 2950 fps to get better performance. However, if you're thinking more like 600-800 yd, you should be fine as it is. You'll still be giving up quite a bit to a good .308 load in terms of wind resistance, but knowing that you can just shoot it and have fun.
[/quote]

At 1000yd, an 80gr A-Max @ 2800fps (500' ASL, 59F, 0% humidity) drifts 109.0" in a 10mph wind using Litz G7.

To match that drift (109.4", to be exact) with a Hornady bullet, the 30cal 178 A-Max needs to be going 2700fps.

175gr SMK, 2675fps (109.1")...155gr SMK Palma 2156, 2820fps (109.2").

Of course, a 30cal Berger Hybrid/Juggernaut will whoop those drifts...at the cost of more powder, recoil, more expensive brass and GREATLY more expensive bullets.

 

[signut]

JBM stats say that an 80 Amax,( Litz's data)going 2850 goes transonic at 1100 yards ( 1071 fps .) ; at 1000 yards it is going 1178 fps. at standard atmospheres. There is no way that it is going 1600fps. at 1K. I think you may have entered an incorrect bullet data in the ballistic program. Just my .02
Also, several of our local shooters have had some issues with the 80 Amax out of 1 in 8 barrels, especially when it gets cool. They "seem" to prefer a 7 twist but that does not mean they won't run out of an 8 twist.

 

[jde650]

According to my hornady load manual 7th addition. The BC for and 80 grain A-max is 0.473 G1, 308 155 grain A-max is 0.435 G1. If you run those figures thru JBM.

223 80 gr @ 2800 fps, wind drift at 1000 is 97.8 in, velocity is 1262. ( 500' elev, 29.62 hg., 59°)
308 155 gr @ 2950 fps wind drift at 1000 is 102.3 in, velocity is 1248. ( same )

So how is the 223 way behind?

jde650

 

[jde650]

I forgot both 260 yard zero.

jde650

 

[MGYSGT]

My wife reminded me the other day that I am not 50 any more. Like many of us, my shoulder hurts enough, without pounding the heck out of it with a lot of recoil. So I will stick with the .223 and work on velocity and bullet selection. I don't really mind the challenge. I thank you all for your input.

Tom

 

[BoilerUP]

...or simply buy a Savage 12LRP or 10 Predator Max in 6.5 Creedmoor and shoot Hornady factory 140gr A-Max ammo, and smoke most any 308 regardless of barrel length or Gucci bullets used ;D

 

[Keith Glasscock]

...or simply buy a Savage 12LRP or 10 Predator Max in 6.5 Creedmoor and shoot Hornady factory 140gr A-Max ammo, and smoke most any 308 regardless of barrel length or Gucci bullets used ;D

Wind drift numbers are one thing. Winning rifles are another....

I'm in the process of specing out a rebarrel of my F-TR rifle so my kid can shoot it. I'm going to go 223 for recoil, but I'm still considering the pros and cons of various bullet choices.

Truth is, I've seen multiple Palma shooters give up on the 223 for long range because it was too fickle. Don't know what the exact problems were, so I'm researching it.

 

[Beau]

The only reason to shoot a .223 @1,000 or, for that matter, a .308 is to comply with Palma or F-TR rules. If you aren't doing either of those, dump those marginal cartridges and pick up a 6 Dasher if you hate recoil.

Throw a dart at a cartridge list and your likely to stick something better for 1,000 than a 223 or 308.

 

[jsthntn247]

If the 90 VLD is so hard to get to shoot consistently, why did Berger discontinue the 90gr long range boat tail match bullet???? Seems the same design as the juggernaut in a 223 would be selling faster than they could make them.