Home Forums Hunting & Shooting Ask The Gunwriters 223 Rem, New school or old school twist rate?

Got the itch for a .223. Things have changed since I last owned one ~15 years ago. There is a multitude of twists now available to stabilize heavier bullets. I am curious about stabilizing 50-55gr bullets in a 1:8 twist. Is 1:8 too much? Do fragile bullets come apart? or is all good and it opens up some options for heavier 60+gr bullets to shoot longer range? Or, just stick with the old 1:12 and forget the heavier bullets. FWIW: Long shots will be 5-600 yards, typical distances ~300.

You will get a wide range of responses.

My thought is- if you are never going to shoot a 75, or even up to a 95 grain bullet, why get the twist needed for those?

SX and TNT (at least the 50 grain version) most likely will not work in a 1 in 8 if driven full speed. 55 TNT may work. Other varmint HP bullets will be fine in it.

For many years, 1 in 14 was a typical twist rate in 223, and it did well with what it was designed for.

For 40-55 grain bullets, accuracy is generally better in slower twists, but there are exceptions. However, pressures are less and velocities can be higher in slower twists.

I've shot a lot of 55 grain bullets through 1:8 twist barrels and accuracy seems fine. Most of my shooting is with 55-77 grain bullets. If you are interested in mostly shooting 40-55 grain bullets maybe a slower twist barrel would be better, but I've had no problems with the 1:8's.

I have 7, 8, and 9 twist .223's. I find 8 twist to be a pretty good compromise. I usually shoot 55 - 65 grain bullets in all. I don't quite get the accuracy I'd like with 69 grain SMK's in my 9 twist gun, but I'm not ready to say it's the twist, I haven't really worked with those bullets in the rifle so much. I've found no problem at all shooting 55's in my 7 and 8 twist rifles. I've never shot anything lighter in .223.

My current .223, a Browning/Miroku Low Wall, has a 1-12 twist and it suits my sensibilities which hover in the 40-55 grain range. Short 60's do ok in it too, but they only return MOA accuracy when it does 1/2MOA with 40 grain Bergers and 52 grain Matchkings. Just me, and my rifle - we have no venues for looong range shooting so the lighter bullets suit us fine.

A bigger thing to keep in mind is the free bore length of the chamber. For a 7-8 twist set up to the longer bullets, the throat length will be excessively long for best accuracy with the shorter bullets.

And to do a 7-8 twist with a short throat for the shorter bullets is double backwards.

It all depends on what you want the gun to do. If you're not interested in lobbing heavies out there a long way, the 12 twists with about .020 freebore length do a great job.

My 2 cents worth....-Al

Al,

Can you explain the above quote? Long, sleek bullets have an ogive that is closer to the case mouth compared to short, blunt bullets. Long bullets typically require a shorter throat than short bullets. If anything, a rifle throated to long, sleek bullets would necessitate light, blunt bullets to be seated quite deep in the case neck to avoid a jam into the lands.

There is no one answer and I think that is understood. I don't get the reason for fast twist in the 223 as it isn't a long range cartridge and is best suited to the 40-50 grain bullets at modest ranges of 350 yards and under.

I have at least 6 223s and I just shoot 40 grain bullets in them and use it for a varmint cartridge. I do have 2 that are fast twist and I need to shoot 55 grain VMax bullets in them to get any accuracy with them.

The 223 could be the best all around varmint cartridge with the 40 grain bullets at 3600 FPS. This is an easy gun to shoot and is capable of great accuracy and will blow a prairie do into the air quite easily.

I would say that if you want heavier 22 caliber bullets, go to the 22-250 sized cartridges...

It has been my experience that longer bullets require longer throats, not shorter.

Can't agree with you there, but that's just me.

My .223 is a Savage Model 10FP medium heavy barrel with. 1/9” twist. It shoots 5 shots you can cover with a dime at 100 yards with Black Hills 68 grain OTM. That’s about as heavy as I shoot from a .223.

Ron

Of course, the descriptors "shorter" and "longer" are too vague to make any definitive statements. I agree that the shortest bullets made in a given caliber will require a shorter throat than the longest bullets made in that caliber, assuming similar seating depth in the case neck. Let's say that the ideal setup includes two assumptions: first, that the magazine doesn't limit OAL within practical limits. Second, that the ideal seating of the bullet is for the base of the bullet body to be seated just above the shoulder-neck junction of the case. Given two bullets of equal weight, the longer, sleeker bullet will require a faster twist rate and a shorter throat than the short, blunt bullet. If we drop enough weight and length from the short bullet (or change its shape enough), I agree that there is a point at which the longer bullet will require a longer throat than the short bullet.

Generally speaking, it's often the case that for long bullets to fit within magazine constraints, they have to be seated deeply and contact the lands at a relatively short BTO length.

My F-T/R .308 has a 0.170" throat for shooting 200gr Bergers. A PALMA reamer might be around 0.050". If I recall correctly, most chambers will be in the 0.085" range.

What's your cartridge overall length?

Still working on what it will end up at, but 3.050" with a 200.20x.

The reason I ask is that's part of the throating vs bullet equation too. I believe F class requires single loading, right?

For many of my purposes I'm constrained by magazine length. In 308, if I load 175 grain VLD Bergers and 150 grain Sierra Pro Hunters to suit the magazine, then the shorter, lighter Sierras will be closer to the rifling.

F-Class is single loading, per rules. You want to keep those long bullets in the neck above the donut, thus the strange free bores. Your standard rifle chamber might be half the free bore as well. 50 thou shorter for the round, plus 85 thou shorter free-bore.

Whatever the freebore length is, in the example I cited where magazine length is the driver the shorter, lighter Sierra remains closer to the lands.

I wish commercial 308's were throated shorter. Seated to 2.8" I'm jumping 168 gr Match Kings nearly 1/8" in a couple.

Searching around does not turn up many 1:12 .223 Rems anymore. Most everything seems to be 1:8. Guess the long range trend has taken over small bore also.

Since I will never shoot anything above a 55 grain bullet I don’t worry about twist. If I were running turrets an shooting long I might would reconsider.


GreggH