Ruger Forum banner
1 - 11 of 11 Posts

·
Registered
Joined
·
32 Posts
Discussion Starter · #1 ·
I have a beautiful M 77 in .223 which I have been trying to reload for for over a year without success. The only modification I've made was to have a Timney trigger installed. I just found out that the barrel twist used when in the .223 when Ruger built my rifle was 1:12. 99.9% of the reloading data published is for a 1:8 twist so now I understand why I was never able to get this gun to shoot the way I would like it to. Can you fellows help me with a bullet, powder, and load combination that will help me get down to 1/2 moa or better.
I am anal about my cartridge preparation so I'm pretty certain the failure to group as tightly as I'd like has nothing to do with my reloads.
 

·
Registered
Joined
·
4,153 Posts
1:12 isn't that uncommon. You're going to have to use lighter bullets however.
 

·
Registered
Joined
·
209 Posts
I’m going to date myself here. Back in the day when I served in the Army, we used M16A1’s. We had a 1:12 twist because we were shooting super speedy little 55 grain M193 bullets back then. So, actually, a very common twist for 5.56/.223, particularly for varmint loads.


GS
 

·
Registered
Joined
·
32 Posts
Discussion Starter · #4 ·
1:12 not uncommon

I realize that the 1:12 may not be uncommon, but I rarely see it mentioned in guns for sale ads or in reloading data. Other than bullet weight should all other factors be the same? Powder brand? Charge weight? What bullet weight would you recommend I try?
 

·
Registered
Joined
·
7,925 Posts
dwcars, a 1:12 twist is good for bullets up 63gr, but that hasn't been my personal experience, I prefer 55gr and liter. My most accurate load is a 55gr Horandy SP over 27grs of CFE223, (26gr min~27.8max).

Some other popular powders for the .223 using bullets 55gr and under are:

AA2015

IMR4895

IMR4064

H335

H332

Benchmark

IMR3031

Varget

IMR4198

If you have any of these powders on hand you're halfway there. Bullet weight will dictate min and max charges, so they will be different. In other words no guessing.
 

·
Registered
Joined
·
209 Posts
Traditionally, but certainly not exclusively, the commercial AR market regarding 5.56/.223 in large part reflected what rate of twist and therefore bullet weight (read length, it’s all about ballistic coefficient of the bullet) the military was/is using at the current time. Because there are so many AR’s in civilian hands, the ammunition manufacturers have responded by offering many more heavy bullet options because you would be hard pressed to find a maker of current AR’s that uses any twist rate other than 1:7 or 1:8 now.

As I said before, when I was in, the rate of twist was 1:12. When the M16A2 came out, the military went to a 1:7 twist. I’m not exactly sure what twist they use in the M4 now, but is probably 1:7 or 1:8 because they shoot 77 grain bullets these days, for the most part. Better ballistic coefficient, therefore, theoretically extending maximum effective range. I say “theoretically “ only because the 5.56/.223 is, IMO, not an effective long range cartridge for use on humans. Yes, it will work, but in the hierarchy of long range cartridges for use on humans, it rates rather poorly. Great for coyotes. Again, my opinion.


GS
 

·
Retired Moderator & Gunsmith
Joined
·
17,226 Posts
I have a Remington 700 that also has a 1:12 twist rate and a 24" barrel. I've found 45 to 55gr bullets group the best, My all time favorite loads are: Speer 52gr Match JHP with 27gr of Varget. 55gr Nosler V-Max bullets with 26.5gr of Varget. These two loads are exceptionally accurate. I've tried several different 62gr bullets and never been able to get accuracy as good as the lighter bullets.
 

·
Registered
Joined
·
4,153 Posts
Iowegan hit the nail on the head. I would certainly try sub 55gr. There's great selections out there for the task at hand.
My favorite powder for 223/5.56 is CFE 223, but my slowest twist is 1:9 in the Mini 14 so I can't attest to your twist. And my fave load/weight thus far in the Mini mirrors Mark204.
 

·
Emperor
Joined
·
885 Posts
I would stick with 55 grain or less.

The twist rate required to gyroscopically stabilize a projectile of any given diameter (caliber) is more a matter of projectile length than weight. If you had two bullets of exactly the same diameter, length, and form factor (shape) but different weight, the heavier bullet would actually require less spin than the lighter one. But since projectiles are generally made out of materials of the same density (lead alloy and copper jacket) a longer bullet is virtually also always heavier.

Nor is the required twist a function of ballistic coefficient, per se. But for rifle bullets of a given caliber, longer projectiles tend to have a higher ballistic coefficient and therefore require more spin, so there is a loose relationship.

And it can also depend on atmospheric conditions. A projectile that is marginally stabilized in dense air might do better in less dense air. Part of the reason the military uses such a fast twist rate for .224 caliber is not only because they need to stabilize long tracer bullets, but they also need to be sure projectiles have adequate stabilization even in cold, dry, dense arctic conditions at sea level. If you plan to do most of your shooting in the summer and live at altitude, you may be able to get by shooting a bit longer (heavier) bullet. It also depends a little bit on what muzzle velocity you achieve with your load.

I don't know how much you want to get into this, but the best rule for determining the required twist rate is generally felt to be the Miller twist rule using the Miller stability factor originally proposed by Don Miller. If you are interested, you can read about it here:

https://bisonballistics.com/Miller-...ist-An-Aid-to-Choosing-Bullets-and-Rifles.pdf
 

·
Corps Commander NGV
Joined
·
6,254 Posts
I am concerned about where the OP is getting his loading data. No manual lists 99.9% of .223 Remington loads for only fast twist barrels. It's a varmint cartridge so tons of data has been published over the years for 40, 45, 50, 52 ,53, and 55 grain projectiles in 12" twist barrels. I have an AR-15 and a Rem 700 .223 with 12" twist tubes. I get great results with 50 to 55 bullets. I usually use 55gr Hornady SP and Nosler Ballistic Tip bullets and Varget or IMR4895 powder. The heaviest bullets I have loaded are 60gr Nosler Partitions.
 
1 - 11 of 11 Posts
Top