.223: Best weight for 1:10 Twist?


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marklbucla
December 31, 2008, 02:18 AM
What is the range of acceptable bullet weights for a 1:10" Twist rate? What is the optimal weight?

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targshooter
December 31, 2008, 07:41 AM
Sierra actually has the following on their 69 grain .223 Match King bullet box:
"7-10 twist bbls. only".
I would suspect, from observation on the target range and other sources, that the 69 grain bullet may not shoot in a 1:10 barrel all that well. The two most common twists offered now are 1:7 (military) and 1:9 (most commercial barrels). I have 1:9 and 1:7; both shoot the 55, 62 and 69 grain bullets accurately. Some shooters have gone with 77 grain bullets, and they are using 1:7 and 1:8 twists. I have not used these bullets.

Accipere
March 13, 2009, 02:51 AM
Can anyone tell me what are the minimum and max bullet weights for a .223 1:9 twist?

cliffy
March 13, 2009, 03:03 AM
Who makes a 1-in-10 inch twist? 60 grainers generally spin-out properly in 1-in-12" and 75 grainers seem happy with 1-in-9" twister barrels, so what is a 1-in-10" happy with? I'd guess perhaps 69 grain fare for target usage, or maybe 64 grain hunting applications? A 1-in-10 inch twister in .223 Remington seens strange but very usable in an odd sort of way.

marklbucla
March 13, 2009, 09:44 AM
Olympic Stainless Ultra Match barrels are 1:10".

After shooting 8 5 shot groups, in my particular Olympic SUM, Brown Bear 55 grain performed better than Wolf 62 grain, which performed better than Wolf 55 grain.

RP88
March 13, 2009, 01:12 PM
Can anyone tell me what are the minimum and max bullet weights for a .223 1:9 twist?

for 1:9, up to about 70 grains will work fine. Super-light varmint rounds might require a step down to 1:10 just in case. Heavier bullets (like 70+ match bullets) work best in fast twists like 1:7.

your 1:9 in general will shoot any standard 55-62 gr round that you'll find as commonplace ammo with no issues.

Ben Shepherd
March 13, 2009, 01:17 PM
1:9 should handle up to 69 grains. 1:10 should hanle up to about 65 grains.

Be aware however, if you have a long 1:9 or faster barrel and push a lightweight lightly constructed varmit slug too fast, it'll blow up.(Most varmit bullet makers list a max velocity for the slug on the box or on thier website)

LTR shooter
March 13, 2009, 02:05 PM
A general guideline fron the site of Shilen barrels and .22 centerfire twist rates.

.224 CF
- 8" for bullets heavier than 70gr.
- 9" for bullets up to 70gr.
- 12" for bullets up to 63gr.
- 14" for bullets up to 55gr.

FWIW - my 1 in 9" 700LTR and Savage 12BVSS both shoot 52 - 69 grain match bullets extremely well.

CB900F
March 13, 2009, 02:24 PM
Marklbucia;

To answer your particular question: Test bullets in the 40 - 55 grain range. Something in there will almost certainly be accurate. There are so many other variables though that you'll have to test for more than just bullet weight. I presume that you're handloading if you're asking about specific bullet weights. Here's the thing, you might have a load that's on the paper but showing pretty miserable groups. Just changing the seating depth of the bullet in the case by .010" may very well turn it into a P-dog killin' load. Or a change of primer, or, or, or, ad infinitum.

900F

Accipere
March 13, 2009, 03:07 PM
Many thanks, all,for useful advice

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