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What bullets for a 9 twist 204????

bobtails

Silver $$ Contributor
I just picked up a 9 twist 204. It’s a AR 20” barrel. I am wondering if it is too fast a twist for Sierra 39 gr blitzkings? Should I be looking at heavier bullets ??
 
I have ran 39 sierras in 9 twist barrels Chambered in 20 Vartarg, 20 PPC, and 20 BR!

They all worked well as long as i did not push them too Hard in that 20 PPC or 20 BR!

You should be ok with the 204 and a 20 inch stick!
 
Call the Sierra tech support line at 800 223 8799 and ask the tech support people. They made the bullets and tested them so they should know.
 
I have never shot the 39 Blitz King or 40 V-Max out of that fast of a twist, so I'll preface by saying I don't know if the twist may be as such to cause bullet disintegration in flight - or whether you could expect to have no issues with over-spin. If that does occur, I suggest trying lead-free 40 V-Max, Barnes Varmint Grenades or Lehigh Defense bullets. The lead-free (especially Barnes) can handle very high speeds and might help. Hopefully those first two will be good.
 
If you take a 1:9 twist 204 bbl with a 204 Ruger chamber, using a Hornady 40 VMax, it is easy to get at least 3600 fps or more.
If you feed that into internal ballistics software you get an Sg = 1.46 which is about the recommended level these days. You could go slower twist and be fine, but the 1:9 isn't too fast for a 40 grain.

Now, if that 1:9 was chambered for 204 Ruger, it wouldn't get a 55 grain up to those speed levels. But lets say it might get 3150 fps, and with that 1:9 twist it would have an Sg = 1.12 which may or may not tip over.

Bottom line is, you can run 40, 39, or 32 grain no problem.
 

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