Hello everyone,

Please help me understand the .223 twist rate - bullet weight connection. I've asked 6 reloading people and received 6 different answers to my question. Here's what I've been told -

1) 1/7 twist is for only 70grain and above bullets.

2) Shooting less than a 70 grain bullet in a 1/7 will cause the bullet to fly apart in flight.

3) 1/9 twist will shoot everything from 50 to 69 grain well.

40 Don't shoot less than 50 grain bullets in 1/9 twist - they'll fly apart.

Please tell me - what is true and what is not. Also, as I have one of each (1/7 & 1/9) I am open to suggestions for ideal varmit bullet weight etc...

Thanks,
Vlad

Vladimir, welcome to the forums. Yes a bullet can be torn apart in flight by the rotational stresses acting upon it's construction. Tis appears sometimes as a bullet trace looking like a tracer (in smoke, color gray) or a puff of gray smoke at some distance from the muzzle. An example of this I have experience is the older Hornady SX (super explosive) .224 diameter bullets being driven over their threshold velocity of 3500 ft/secs through a 1 in 14 twist. Later I tried some of these bullets at about 3200 ft/secs in a 1 in 9 twist and the same result. Bottom line is there are many factors, but yes, catastrophic bullet failure is real.

Vlad,
I shoot a 1 in 8 Rock River 223 and find it likes anything under 69 grains.
When I try 80 gr VLD I start to see keyholing- it has to do with the lenght of the projectile more than the weight although they are obviously linked.
As to the "vaporization" of the lighter bullets, only have seen it occur with the SX type of thin skinned varmit rounds driven to excessive rpm's.
Can do it every time in my 22-250 with a 40 grain pill up around 3900 fps.

Interestingly, I shoot a Colt Accurized rifle with a 24" 1 in 9 twist and have been able to stablize the 75 Hornady A-MAX and the 77 grain Sierra bullets without difficulty. The first loaded long-single feed, the second at magazine length. The body size of your varmints should have something to do with your choice of bullet, as Pdogs are one thing and wolves another.

quote:

1) 1/7 twist is for only 70grain and above bullets.

this seems a reasonable statement

quote:

2) Shooting less than a 70 grain bullet in a 1/7 will cause the bullet to fly apart in flight.

maybe....some bullets will not tolerate this RPM

quote:

3) 1/9 twist will shoot everything from 50 to 69 grain well.

It will also shoot the 40 grain bullets well.

A few bullets such as Sierra's blitz and Hornady's SX are very fragile and these might come apart at high velocities with 1-9 twist.

quote:

4) Don't shoot less than 50 grain bullets in 1/9 twist - they'll fly apart.

I've not found this to be true at all.

Here's a statement that you can believe in....Get ya a 223 with a 1-12 twist and it'll shoot 40 to 60 grain bullets well. The only time you really need faster twists is when you decide you want to shoot very heavy bullets and I've yet to find that desire.

The 223 is a spectacular performer with 40-45-and 50 grain bullets and will work well from 1-12 (or 1-9) twist and I am delighted with the way it works with a 50 grain Speer TNT

So....what bullet do you really want to shoot in this 223?

It would be real hard to load a 223 to the point you would see bullets ripping apart in flight. That usually occurs in Swifts, 22-250, wildcats, etc. Any game you want to shoot at any bullet weight is now manufactured. Define your quarry, choose a bullet type and find it in a adequate weight.

Perry

You all might find the artical (Barrel Twist, Bullet Stability & Rifle Accuracy ) in the June 2005 Shooting Times Mag some help.

I load for a .222 Remington and a .22/250 Remington both with 1:12 twist barrels. They both shoot Speer 70 grain Semi-spitzers well (less than 1 MOA).

Here is what I have seen with my two .223's.

My Savage 12FV (1-9 twist) will shoot everything between 50 and 60 grains (haven't loaded anything heavier), but 40 and 45 gr VMAX do not group well, and at times it appears the tips seperate.

My RRA AR15 loves 55gr VMAX's (also a 1-9 twist). The only 45 I have tried to shoot were some Ultramax NBT's that I had laying around, and they didn't work well at all.

For my rifles, they like the heavier bullets. However I have seen guys at the range shooting 45 gr bullets out of 1-9 barrels and having great groups. Just depends what your rifle likes to eat.

My 1/9 barrel shoots 45gr Sierras very accurately.

A 7.53 inch twist rate (191mm) is optimal for a .224 inch (5.56mm) diameter ONE INCH LONG (25.4mm)spitzer bullet over the 2600 to 3300 fps MV range. All you need to do is scale this twist rate up or down as a function of the actual bullet length in question to the reference length of 1 inch.If the bullet is half an inch, it needs twice the twist rate, or about 15 inches, i.e., divide 1 by the length you measure and multiply times 7.53.

I am sure it can be done, but I have not been able to acheive the spin to get a bullet to fly apart.

I have done 4,127 fps with 33 gr Vmax in a 1 in 12" barrel and it still shoots a group.

That would be 247,620 r.p.m.

How fast do I have to spin a bullet?

quote:

Originally posted by tuck 2:
You all might find the artical (Barrel Twist, Bullet Stability & Rifle Accuracy ) in the June 2005 Shooting Times Mag some help.

Load sierra "Blitz" bullets much over 3500fps in anything and you have a potential to see "blue streaks" and "smoke puffs"
Partcularly if you get the barrel hot OR the
barrel is old and/or a bit rough...
and that's with a 1:12" twist barrel

with a 1:9 or a 1:8 it becomes much easier to overspeed/overspin the lighter bullets with max loads.

Frankly I just don't see the point in heavy bullets in the 223Rem(in particular) or 22CF's
(in general) for "normal" purposes.
Unless you are shooting a "match rifle" where 223Rem is required by the rules anything you THINK you can do with the heavier bullets is probably better done with the lighter ones....

My thought is that if I want to toss 70gr (or heavier) bullets at woodchucks I'll use a 6mm or 25caliber to do so...

So I'm fine with the 1:12" twist in my Remington 700VSSF.

as for bullets "blowing apart" in flight?
I could blow 75gr hornady hollowpoints at will in my 25-06 just before I retired the barrel.

about 15 years ago I had a fun afternoon at Range14 in FtDix (FtDix Rod&Gun Club) with a friend, we could almost predictably determine where in flight the bullet woud disintigrate be varying the time between shots (thus varying barrel temp) only if the barrel was dead cold would the bullets actually get to the 200yard target intact.
But that was a special circumstance as I KNEW
the barrel was junk and was at the range specifically to burn up a batch of ammunition
in neck sized brass specific to that barrel
as I was dropping that rifle off at the gunsmith's Monday morning to have it rebarreled to another caliber.

AllanD