06 March 2004, 16:49
7-30 WatersRate of twist question
Will a 1:9 twist stabilize 80 grain bullets in a 223 Remington of do I need a faster twist? If a faster twist is needed what do you all recommend?
08 March 2004, 10:34
<eldeguello>At least 1/7.5" for an 80-grain POINTED .224" bullet. The 1/9 MOGHT stabilize a roundnose. But I'd consider it marginal. Measure the length of your bullet, then use the Greenhill formula to calculate the twist needed:
required twist (in CALIBERS) = 150/length of bullet (IN CALIBERS).

09 March 2004, 03:42
DutchIn Nebraska, no. At my elevation (5,000 feet), yes. HTH, Dutch.
09 March 2004, 04:12
MuleriderHighpower competitors using AR-15's use either 1:8 or 1:7 twist for the Sierra or Nosler 80's, and the Hornady 75 A-Max. Never heard of a 80gr round nose .224 bullet.
1:9 twist will stabilize the Sierra 69gr Matchking, and often the Horn 75 bthp (but marginal).
What will you be using the heavy bullets for?
10 March 2004, 04:24
Red Neck641 in 7.1/2 is what I come up with.
10 March 2004, 10:47
7-30 WatersI was thinking of getting a custom barrel for my Contender. My local rifle club has shoots where they have an open "F" class for high powers. Any gun/sights can be used. Thought a 223 would be a good choice and exexpensive to load for.
10 March 2004, 16:49
Mulerider7-30: will you be shooting out to 600yds (or more)?
Just wondering about the need for 80 grainers. A 1:8 twist (and maybe the 1:7) will still shoot the lighter bullets quite well, so there is not much of a down side as to fast twist. However, loading a 80gr will require a fairly long throat/leade for bullet seating, something to think about when trying to wring out all you can out of a 223.
Some Highpower shooters have gone to the 1:6.5 twist PacNor barrels in their 223's, in order to use 90gr JLK bullets. Like shooting a pencil!