Re-barreling .223; What best twist rate for stabilizing 69gr MK's 1:9 or 1:10 ?

[Central Desert]

Considering re-barreling my .223, interested in what is the best twist rate to stabilize 69gr match kings ?

 

[ab_bentley]

If you were me, I'd use an 8" twist.

Adam

 

[L.Sherm]

If you were me, I'd use an 8" twist.

Adam

+1

 

[mac86951]

1:9 will do it, 1:8 is a better idea.

1:10 would leave questions of temperature, altitude and range for stabilization.

 

[Shynloco]

If you were me, I'd use an 8" twist.

Adam

+1. Proved to be the best in both my .223 bolt gun and custom AR.

Alex

 

[DHD]

Personally, since I will shoot at longer ranges, I build every rifle with a twist that will stabilize long range bullets for caliber.

You may never shoot a bullet heavier than 55 grains, but I bet you will. Go with what has already been suggested (1-8), and never look back.

 

[Central Desert]

Cheers thanks all

 

[joshb]

1 in 8 works for me! Factory Tikka T3. My first 8 and it shoots.

 

[LCazador]

Considering re-barreling my .223, interested in what is the best twist rate to stabilize 69gr match kings ?

If you're going to err on twist rate, it's always better to be on the plus side, 8 twist and it will still work with 53's or 55's. A nine will get you by.

 

[Cold Bore]

If you're going to err on twist rate, it's always better to be on the plus side, 8 twist and it will still work with 53's or 55's.

In the 223 Rem, this is wise advice.

A 1-10" will be marginal at best with 69's.

1-9" will work, 1-8" will give you the option of moving up to the 75-77 grain stuff.

The 1-10" barrels are sort of no-man's land. You can shoot the lighter stuff from a 1-12", but need to step past the 10-twist if moving up in weight. Can't see much reason to barrel a 223 in a 10-twist.

We shot tons of 55 grain stuff out of 1-7" M-16 A2 models in the military with no ill effects at all, so a bit of "over twist" won't hurt (within reason), but that doesn't work in reverse.

 

[P72]

I have used 10, 9, 8, & 7.7 twist barrels. I would go for the 8 twist for 69's - this will also shoot 52's and 53's and 75's as well. A slower twist might be perfect for a shorter bullet but a total failure for a longer bullet. I always prefer practicality and good results over perfection. Take a look at the Miller twist program that can be accessed on-line on the Berger site.

My old 1-10 twist .22-.250 was real marginal with 68 Hornady's , printed great sideways bullet profiles at 100 yards with 75 Amax's when I could hit the target (failure) but was close to perfect with 53 Vmax's.

 

[Huckleberry75]

If you were me, I'd use an 8" twist.

Adam

This^^^ if that is as heavy as you are going to go. If you want to shoot the 80gn Amax or SMK, then step up to a 7tw.

 

[manitou210]

For best results in 223 rem go with a 1/7 twist and shoot 80 gr bullets.
get your smith to make throat longer.
I have done the 69 gr bullets and they don't run against the 80s or 90s.
Note what Berger claims for twist on 80.5 it has be revised down to 7T from 8T
Quantity = 100

G7 BC = 0.226

G1 BC = 0.441

Optimal Twist = 1:7"

 

[ab_bentley]

For best results in 223 rem go with a 1/7 twist and shoot 80 gr bullets.
get your smith to make throat longer.
I have done the 69 gr bullets and they don't run against the 80s or 90s.
Note what Berger claims for twist on 80.5 it has be revised down to 7T from 8T
Quantity = 100

G7 BC = 0.226

G1 BC = 0.441

Optimal Twist = 1:7"